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ADVANCING CAM TIMING 2-4*

Posted By: Labratt

ADVANCING CAM TIMING 2-4* - 09/26/10 03:40 AM

I know it's still a little early to start pulling the 440 apart,but as soon as my neck allows it,I was seriously thinking about advancing my Comp solid 2-4* for some improved 60' times! It's installed at 5* ICL as checked, when installed 2 yrs. ago! Specs are .614I...620E,262@.050I..266@.050E..108 LSA,installed at 105* 60's range from 1.52-1.60. What is the consensus? Thanks for your opinions in advance!

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Posted By: BradH

Re: ADVANCING CAM TIMING 2-4* - 09/26/10 02:39 PM

It's a 108 LSA installed on 105 already? Don't bother looking for gains from advancing it any more. Try a 4-hole spacer, different accel. pump cams, different pump nozzle sizes, different launch RPM, etc., if you're looking for better 60-ft. times. Naturally, just my ...
Posted By: ZIPPY

Re: ADVANCING CAM TIMING 2-4* - 09/26/10 02:57 PM

Randy what was the 1/4 et/mph when it went 1.52?
Posted By: 68LAR

Re: ADVANCING CAM TIMING 2-4* - 09/26/10 03:22 PM

Quote:

60's range from 1.52-1.60.


Randy, my you won't see much of a gain.
Seeing .08 spread in your short times seems to indicate you have to look at launch technique. Did you keep the 1.52 time slip? How did you launch with that run? Sometimes little things like leaving from an idle, or putting a little load on the converter make a big difference. Again, my .
Posted By: 440Jim

Re: ADVANCING CAM TIMING 2-4* - 09/26/10 03:59 PM

My initial thought is there isn't much to be had there, but maybe a little. Assuming 446 CID, 12 CR, 5000 stall, etc.

What compression ratio are you running?
What CID? (446?)
What heads?
What header primary dia and length?
Converter stall, gear, tire dia, etc?
Posted By: 602heavy

Re: ADVANCING CAM TIMING 2-4* - 09/26/10 04:33 PM

Opinions are good , whether right or not is another matter...............not knowing all the details is difficult to say , advancing ICL (earlier opening Ex valve) could rob some power bearing in mind CR & split pattern , generally not a fan of split pattern grinds unless using power adders.

Posted By: Labratt

Re: ADVANCING CAM TIMING 2-4* - 09/26/10 05:09 PM

Zippy..my bad! My best 60' was actually a 1.54,not 1.52! My et was 11.27 @ 119,when we were at Lapeer this past spring!Jim, my CR is 10.25..448 CID..stock Eddy RPM's.TTI 2"x 3.5" collectors! Can't recall the length. Converter's a Dynamic 9.5" that flashes to 4500 rpm. Slicks are 29"x 9" wide. Rear gear ratio is a 4:56. Race weight with driver is 3740 lbs. So..maybe experiment with the squirters and pump cams? Another idea was to get the Eddy's CNC ported by Modern. Hopefully,that change alone will put me into the 10's!
Posted By: 440Jim

Re: ADVANCING CAM TIMING 2-4* - 09/26/10 05:15 PM

IMO, 10.2 CR isn't enough for a 262/266 cam; so you are giving up some in that area. You can try the cam installed position, it is time and labor not money. Having the heads done by MCH will definitely make a big improvement and mill them for smaller chambers, more CR, while they are out.

3740 lbs is a lot of weight to move, so you are doing OK.
Posted By: Darryls-Demon

Re: ADVANCING CAM TIMING 2-4* - 09/26/10 06:09 PM

Do the heads.
Posted By: emarine01

Re: ADVANCING CAM TIMING 2-4* - 09/26/10 07:33 PM

Quote:

IMO, 10.2 CR isn't enough for a 262/266 cam; so you are giving up some in that area. You can try the cam installed position, it is time and labor not money. Having the heads done by MCH will definitely make a big improvement and mill them for smaller chambers, more CR, while they are out.

3740 lbs is a lot of weight to move, so you are doing OK.

We camed down 18 degrees with 12 to 1 from 280@.050 to 262 a hair small in duration and found major torque gains
Posted By: MR_P_BODY

Re: ADVANCING CAM TIMING 2-4* - 09/26/10 07:39 PM

Randy I would advance it... might try it at 100 to 102
to pick up some torque which will bring the stall up
some on the converter... but advancing it will cut some
of the high rpm's
Posted By: Labratt

Re: ADVANCING CAM TIMING 2-4* - 09/26/10 08:20 PM

Thanks Guys! If I do get the heads done,what would you guys bring the compression up to? Was SERIOUSLY thinking of converting over to E-85! 12:1? I know that would definately improve the torque output,and take advantage of the 262/266@.050 duration!
Posted By: deaks

Re: ADVANCING CAM TIMING 2-4* - 09/26/10 10:37 PM

I had my edelbrocks milled .050 and used copper coated steel shims to get mine up to 11.1, quench was right at .040.
Posted By: B G Racing

Re: ADVANCING CAM TIMING 2-4* - 09/26/10 11:49 PM

You won't see much at 2 degrees advance,but at 4 degrees you will see your torque and hp curve sooner at lower rpms.
Posted By: Sport440

Re: ADVANCING CAM TIMING 2-4* - 09/27/10 12:39 AM

First off, I think your combos running really good. If you do nothing to your heads I would try advancing it 4* to around 101* ICL. That is if ?? your P/V clearence will allow that. I wouldnt waste my time with just 2*

o you still have time to do this yet this season, If so I would try it

If not, and your really considering doing the heads. I agree about having Modern cnc port them and give them about a .050 shave to bump up your comp. to about 10.75 or so.

To get to 12.1 you will need 0 deck pistons and a .070 shave. I wouldnt bother IMO, Id keep it 11.1 max with that cam so you could still run pump gas if you need to.

E85, I wouldnt touch it. That stuff sucks I hear. mike


PS, I PM,ed. you back but your mail box was full, about Norwalk!
Posted By: sk68gtx

Re: ADVANCING CAM TIMING 2-4* - 09/27/10 01:09 AM

You might want to check where it is at now, depending on the number of passes and how much RPM it has seen the chain might have a few degrees of stretch in it? Bob P.
Posted By: Labratt

Re: ADVANCING CAM TIMING 2-4* - 09/27/10 02:36 AM

Thanks Guys! How about advancing the cam 4* and CNCing the heads,without changing the CR? Would it adversly affect the top-end MPH that much? Or would the improved torque gain be worth it? The car is heavy @ 3740 race weight! Thanks!

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Posted By: Dodgem

Re: ADVANCING CAM TIMING 2-4* - 09/27/10 05:17 AM

I'm sure putting it @ 102 or 101 will really help your 1/4 times likely enough to go 10's and another .3 for ported heads!
Posted By: HardcoreB

Re: ADVANCING CAM TIMING 2-4* - 09/27/10 02:11 PM

Quote:

... What is the consensus? Thanks for your opinions in advance!


Someone or maybe many have said to up the compression via milling some off during the refresh . Nothing wrong with 11.5 to 1 or slightly less CR IMO (with good quench!!!). That'll bring that cam and its current position into optimum(wording make sense? )LOL. I don't know if moving it from its current position would help a bunch...did you measure current cranking compression?
Posted By: tboomer

Re: ADVANCING CAM TIMING 2-4* - 09/27/10 02:59 PM

I am for porting the headss,Randy. Remember a few years back when we were discussing rods? If you can spring for a set of Eagles or K-1s,it may be a good time to considor that,too!!
Posted By: Labratt

Re: ADVANCING CAM TIMING 2-4* - 09/27/10 06:39 PM

T-Boom..if I'm lucky enough to be able to afford the head work..new rods will have to wait..regretfully! Sean,I agree 100%..11.5,or even 12:1 should still be streetable with a good quench! My cranking pressures were 185 when I checked this last spring! How much of a horsepower gain can I expect with the added air flow,and more compression? How much higher would my peak horsepower be? Right now it's 6000rpm. I cross the stripe at 65-6600rpm with 30" slicks and a 4:56 gear! Thanks for ALL your ideas and opinions! I REALLY want to be able to turn this GTX into a "streetable" 10 second car!

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Posted By: Labratt

Re: ADVANCING CAM TIMING 2-4* - 09/28/10 01:33 AM

NIGHT TIME
Posted By: Sport440

Re: ADVANCING CAM TIMING 2-4* - 09/28/10 03:54 AM

Randy, Streetable is a matter of opinion. When you ask about a compression increase, how far are you willing to go.

Are you thinking of the attainable gains of the head shave alone or are you considering swapping pistons too.


With a head shave alone and depending on your current piston depth your limited with a compression increase by a "reasonable" head shave. To me, that would be around .060 max. 12.1 may not be attainable.


IMO, 11.1 comp is what Id be looking at. Your current 185 comp psi @ 10.25 is already in detonation Zone with typical pump gas. Id double check that pressure with another gauge. mike
Posted By: Labratt

Re: ADVANCING CAM TIMING 2-4* - 09/28/10 05:40 AM

Thanks Mike! I'll check the cranking pressure with another gauge! In your opinion..with doing nothing else but CNCing the heads and getting a GOOD valve job..what gains in MPH..and ET could I expect? Gary Jacob thinks I should pick up 75-80 hp with porting alone!???? What's your opinion??? Thanks again! RandyB
Posted By: topbrent

Re: ADVANCING CAM TIMING 2-4* - 09/28/10 07:02 AM

Quote:

In your opinion..with doing nothing else but CNCing the heads and getting a GOOD valve job..what gains in MPH..and ET could I expect? Gary Jacob thinks I should pick up 75-80 hp with porting alone!???? What's your opinion??? Thanks again! RandyB



Bear with me, as I have posted this chart before, but here is a test that was done by Dulcich directly comparing the out of the box Edelbrock RPM heads to Modern Cylinder Head CNC Edelbrock RPM heads.

Granted, this is one mans test, but I think this test data directly applies to your question, as the specs of this engine are extremely close to yours.
Same CI, same compression, similar intake, same stock heads, ect.

Given the similarities, I would think your larger , 260°/266°(SQ lobes) 108°lsa cam should make more power than the smaller 243°/247° (MM lobes) 110°lsa cam used in this test.

Horsepower gains from MCH-CNC RPM Heads: see attachment
4800rpm + 17hp
5000rpm + 20hp.
5200rpm + 28hp
5400rpm + 36hp
5600rpm + 38hp
5800rpm + 39hp
6000rpm + 45hp
6200rpm + 41hp

Given these kind of gains, CNC porting your heads would probably net you the .20'ish ET needed to obtain your 10 second timeslip.

Test engine 448" combo:
- Speed-Pro-2355 pistons, 10.2 compression
- Comp MM Flat tappet cam, 243°/247° @.050, .586/.597 lift, 110°LSA, 106° installed
- Comp 1.6 Roller rockers
- Victor Intake
- TTI 2-2/18 headers

(click the attachment for a larger view)

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Posted By: Labratt

Re: ADVANCING CAM TIMING 2-4* - 09/28/10 01:30 PM

Brent..can't get much closer than that on engine specs..except I do have a bit more duration! I would expect even more of a HP gain just because of my larger duration! Maybe closer to 60HP!? Lots to think about before taking the heads over to Jeff! Bumping the CR to 11:1 probably wouldn't hurt either! RandyB
Posted By: BradH

Re: ADVANCING CAM TIMING 2-4* - 09/28/10 02:27 PM

You'd probably see a comparable 40 HP improvement from the ported heads, regardless of cam differences. At your current performance level, that "should" translate into a .3+ and 3+ MPH improvement.
Posted By: JAKE68

Re: ADVANCING CAM TIMING 2-4* - 09/28/10 02:28 PM

Look at the torque no.s thats a nice improvment. That would move that car. We had some ported 915 heads with 500 in. .590 cam motor that went 10.90's put on a set of Jeffs 440 sorce heads on and the car now goes 10.30's
Posted By: HardcoreB

Re: ADVANCING CAM TIMING 2-4* - 09/28/10 02:46 PM

I'd think of your potential gains this way...How much power does your 448"/OOTB Edelbrock motor make now? Now intergrade optimal 'street-friendly' compression and good porting. I'd guess your gains .2-.3 tenths maximum. If your still using the same intake and carb. it will limit the total performance potential of the new porting. Ultimately the hard parts your using will net about 600 HP optimised.
Posted By: Labratt

Re: ADVANCING CAM TIMING 2-4* - 09/28/10 06:03 PM

So Brad,Gary,Sean..just by porting the heads and getting a GOOD valve job,I should be running 10's in good weather conditions? Also,I would most likely get the heads milled for 11:1 compression! I see no problem with good premium pump gas! I run the timing at 39* total right now..if need be,I could bring it down a few notches to 35* or 36* wihout losing much in the power department! My BIG contemplation is advancing the cam timing to 100-101 for improved torque down low! What do you guys think I would lose on the top-end by doing that,though? Thanks for ALL your ideas guys,I REALLY appreciate the help! BTW..Gary..You do realize if these changes go according to plan,you will be seeing me in the spring..with YOU on the dyno!!!

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Posted By: JAKE68

Re: ADVANCING CAM TIMING 2-4* - 09/28/10 07:58 PM

Randy, I am sitting here thinking of your question If I had to guess you would pick up et and loose some mph? Maybe. Or pick up some et and no gain on mph. I look forward to doing some tuning.!!!!!!!!!!!!!!!!!!!!!!!!
Posted By: Labratt

Re: ADVANCING CAM TIMING 2-4* - 09/28/10 10:00 PM

Gary..do you think the increased air-flow from porting would cancel out the lost top-end from the 4* cam advance? Even if I lose .2-.3 on the ET,and stay at 119-120,I'll be a "Happy Camper"! As long as I get a 10 second time slip in my grubby little hands!
Posted By: topbrent

Re: ADVANCING CAM TIMING 2-4* - 09/28/10 11:20 PM

Quote:

..just by porting the heads and getting a GOOD valve job,I should be running 10's in good weather conditions?



Randy, you keep referring porting the heads and getting a GOOD valve job as separate things.

Is there something you feel is wrong or lacking with the valve job that Jeff @ MCH gives the heads when he CNC ports them?

His list of clients is pretty impressive and most seem very satisfied with his work and the results of his labor. I have heard nothing buck good about his work. Just curious if you know or have heard something otherwise.
Posted By: ZIPPY

Re: ADVANCING CAM TIMING 2-4* - 09/29/10 12:00 AM

There's no doubt ported and milled heads would, most likely, get it where Randy wants it to go. Simple one stop shopping.

But I'm wondering if all the low buck tricks haven't been used up yet?

Randy I noticed you had some sort of cutouts in the exhaust? Being that the car is trailered, why not take the pipes off completely to save a few lbs and put collector extensions on?

Open headers was worth 40 ft lbs in mine, back when it used to have 3" exhaust, St Dominator intake, 850, smaller headers etc. If I hadn't limited myself to no trailer/being too broke to buy one anyway/must run through the exhaust, I would have made alot less work for myself......

Another thing, the car has both a clutch fan AND an electric fan on it. Why not take the clutch fan off completely at the track? It might make a difference.
Posted By: Labratt

Re: ADVANCING CAM TIMING 2-4* - 09/29/10 04:05 AM

Brent..in NO WAY am I insinuating Jeff doesn't do excellent valve jobs! I just know the Eddy's have a bad reputation of not-so-good quality from the factory! I was just INCLUDING..emphasizing..the positive effects of a top-notch valve job,when he ports and mills the heads! I believe he also puts a back-cut on the intake valve for better flow! Zipster..I just might pull the exhaust off and bolt up an extension to the collectors..what length would ya' suggest? Taking the clutch fan off might be a good idea also! Thanks Guys! RandyB Rich..do you think advancing the cam 4* would kill too much top-end power? If so..I might just leave it at 105*

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Posted By: dulcich

Re: ADVANCING CAM TIMING 2-4* - 09/29/10 05:05 AM

I would advance it to 102, and run it there. You will likely pick up low end, and I would be willing to bet you will not notice any loss in top-end power. Many times the cam timing thing is not a direct "take from here and give to there" trade-off. Usually with a fairly long cam and less than optimal compression, you will gain torque at the bottom advancing far more than you will lose top-end.

The change will be moderate, so don't expect a night and day difference, especially with a good amount of stall and the cam already in at 105. The ported heads and higher compression would be much more dramatic, but of course a cam timing change doesn't cost anything.

Not wanting to be a master of the obvious here, but if you want to go for the big step up, Jeff's porting works very well on the E-heads, and you can increase the compression at the same time with milling. Jeff is the real deal from the work I've seen. Frankly, at the risk of sounding like a jerk, I have also seen plenty of work by various internet board "heros", here and elsewhere that is average at best. Only a select few are really accomplished at port work.

I would have no hesitation to run it at 11:1 or even 11.5:1 on pump gas with good quench and aluminum heads in street/strip application with a 260+ cam.
-dulcich
Posted By: firefighter3931

Re: ADVANCING CAM TIMING 2-4* - 09/29/10 05:10 AM

Randy, if it's currently making peak power at 6000 advancing the cam is only going to make it nose over sooner, inmo.

I like plan B which involves porting the heads and bumping the compression up to spike the torque and carry the horsepower. My only concern with that scenario is the resulting PV clearance after the heads are cut.


Ron
Posted By: Labratt

Re: ADVANCING CAM TIMING 2-4* - 09/29/10 05:23 AM

Yeah,Ron..I was wondering the same thing on the P/V clearance also! Will have to check it before taking the heads over to Jeff! Sounds like I'll just leave the ICL at 105*! Don't want to drop peak HP any lower than 6000! Do you think after porting the heads,the peak HP will increase very much,if at all? Thanks!
Posted By: quick77rt

Re: ADVANCING CAM TIMING 2-4* - 09/29/10 05:40 AM


I love your car by the way, that year and color, I painted a KZ900 that color as well. Anyway...

I like this reply, it seems im on the right track. Maybe as far as advance goes.

My cam is a solid in the 270s intake 280s in the ex, at approx 8k ft actual altitude im about 45 plus pounds down on cranking comp so my cam is advanced 4 degrees to bring the powerband down a bit and with a 4 inch crank and .033 quench, al heads, almost 11.1 its one of my better running combos.

The cam advanced 4 degrees sets mine at 102 as well and produces enough tq to launch the car just as the cam comes on hard, (Foot brake to 3800)Can go 4300 on the brake. It says it likes 4000-7400 but with the longer stroke it likes 7200 vs 7400 and falls hard off at 7600. And it pulls hard to the 7-7200 area....I think I got lucky.

I guess im using the low end tq to launch and drive into the cam and I think if setup is semi right it makes a great street strip car.



Quote:

I would advance it to 102, and run it there. You will likely pick up low end, and I would be willing to bet you will not notice any loss in top-end power. Many times the cam timing thing is not a direct "take from here and give to there" trade-off. Usually with a fairly long cam and less than optimal compression, you will gain torque at the bottom advancing far more than you will lose top-end.

The change will be moderate, so don't expect a night and day difference, especially with a good amount of stall and the cam already in at 105. The ported heads and higher compression would be much more dramatic, but of course a cam timing change doesn't cost anything.

Not wanting to be a master of the obvious here, but if you want to go for the big step up, Jeff's porting works very well on the E-heads, and you can increase the compression at the same time with milling. Jeff is the real deal from the work I've seen. Frankly, at the risk of sounding like a jerk, I have also seen plenty of work by various internet board "heros", here and elsewhere that is average at best. Only a select few are really accomplished at port work.

I would have no hesitation to run it at 11:1 or even 11.5:1 on pump gas with good quench and aluminum heads in street/strip application with a 260+ cam.
-dulcich

Posted By: Labratt

Re: ADVANCING CAM TIMING 2-4* - 09/29/10 03:18 PM

Mark,Ron,Steve...For me, there are only 2 head porters that I would use..not that there's not a LOT of good ones out there,but Jeff at Modern is only 30 minutes from my house,and I do know him from past help he and his brother,Bob,have given me, when I installed my Comp SQ lobe cam 2 yrs. ago! They're BOTH GOOD GUYS! The other,who actually picked out my cam,is Dwayne Porter..another GREAT GUY! Can't go wrong with either one of them! What Steve said on advancing only 2* makes sense. Might not make a big difference,but should help torque some..without giving up any top-end power! Sooo..2* advance..CNC'd heads..mill heads for 11-11.5 CR,if I have the clearance..collector extension..remove clutch fan..sounds like a solid recipe for a 10 second time slip..in good air!
Posted By: ZIPPY

Re: ADVANCING CAM TIMING 2-4* - 09/29/10 03:50 PM

There's only one way to know on advancing the cam... The only type of motor I have ever deliberately done that on is low compression/small or stock cam beaters... You know, the stock '73-up 360 or 400 in a barge with 2.76 gears...I've had several...it works every time in that application but yours? I'm not so sure. Go with your gut. No matter what happens it'll give you some pretty valuable info.

Have you opened the lash yet to see if that has any effect? .003 or so looser than normal for a pass or two might make a difference.

If advancing the cam and/or opening the lash makes a huge change for the better, if there appears to be some "magic" in it, then (personally) I might start to wonder if it really had the right cam to begin with, but that's just the way my feeble mind works....

Mr. P has experience with collector extensions and can probably get you in the ballpark right quick. I think the usual rule of thumb is start with about 24" and go from there.
Posted By: Labratt

Re: ADVANCING CAM TIMING 2-4* - 09/29/10 04:06 PM

Zippity..never opened up the lash past what Comp calls for! Actually set them .004 tighter for quieter street operation! Don't get me wrong..I LOVE this cam Dwayne Porter picked out for me..just trying to find a little more bottom-end torque,coming off the line! What effect on the peak HP and TQ RPM do you think making said changes will produce??? Peak torque is at 5200,and Peak HP is 6000.
Posted By: ZIPPY

Re: ADVANCING CAM TIMING 2-4* - 09/29/10 08:19 PM

Collector extensions and/or X pipe shouldn't change peak tq rpm at all....peak should stay about the same but it will be fatter at and below the peak=it should hit harder regardless of what else is done.

That was why I was asking if you ever considered that. It won't shift the peak down 500-700 rpm where it will match the converter better but it will help with everything else you already have.

But will it get you into the 10s?
Probably not, without other changes

Posted By: BradH

Re: ADVANCING CAM TIMING 2-4* - 09/29/10 08:32 PM

My 440's 266/266, 108 LSA cam is also installed on a 105 ICL. My CR is 10.8:1. My Dynamic 9.5" converter flashes to approx. 4500 from a 1800 launch off the foot. I've tested "a bunch" of different things and whittled my 60-ft. down to 1.45-1.46 on 275/60R15 DOT drag radials. Car & driver is 3750+ #s, so it's not a lightweight.

IMO, raise your CR some, get the heads ported, and spend some time tuning the effer. Leave the cam ICL where it is so you know what gains resulted from the CR & porting. Oh, maybe put some 1.6 intake rockers (intakes only) on to help use the improved high-lift flow of the ported heads.

Yes, you can loosen up the lash .004" from your normal setting to see if it "likes" a slightly shorter duration. Check w/ Dwayne or COMP on what the min / max lash for your cam's lobes are, since there is usually an acceptable range to run. My XX lobes are usually listed as running .020", but are OK running from .016-.024" (hot).

All out of opinions on this subject...
Posted By: Sport440

Re: ADVANCING CAM TIMING 2-4* - 09/30/10 12:39 AM

Quote:

Zippity..never opened up the lash past what Comp calls for! Actually set them .004 tighter for quieter street operation! Don't get me wrong..I LOVE this cam Dwayne Porter picked out for me..just trying to find a little more bottom-end torque,coming off the line! What effect on the peak HP and TQ RPM do you think making said changes will produce??? Peak torque is at 5200,and Peak HP is 6000.





Randy, IMO your Waay to worried about losing top end by advancing your cam by 3 or 4 more degrees.

Dont worry about it, you will be fine with that 260* cam. It will still pull way more RPM then you will need.

Do worry about posible P/V clearence though.

Advancing the cam will give you less on the intake valve as will shaving the head. Do you know your current clearences?? If so you can calculate the amount of shave and advance you can utilize.


IMO, I would do All 3 things on the shopping list to ensure a solid 10. sec. time slip.


For right now, I would try advancing it to 101* and get it To the track one more time should cost you hardly anything.

Plus, add in some of Zippys and Brad H,s tricks. You could see a ten, maybe.


Over the winter , I would send the heads to Jeff for a CNC port and a head shave to at least a 11.1 if P/V clearences allow.

Between these 3 things, you will have your 10.?? slip, easily on even a bad day if your suspension works. mike


Posted By: Labratt

Re: ADVANCING CAM TIMING 2-4* - 09/30/10 03:43 AM

Thanks for your advice,Rich! Brad,I'm currently using Crane 1.6 ductile rockers. Thanks for your ideas as well! Mike..track time has to wait until next year,since I just had a 3-level cervical fusion last Monday! Mike,if you think a 4* advance won't diminish my top-end all that much,I'm willing to try it!Could that change alone net me a 1.48-1.50 60' time? That sounds good! We'll see how it all transpires over the winter! And Mike..I'm not quite ready to let the (F-5 green)car go just yet! Thanks a Bunch Guys!!! Almost forgot...what do you guys think the peak horsepower RPM will be with the ported heads and a 4* advance?

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Posted By: Labratt

Re: ADVANCING CAM TIMING 2-4* - 09/30/10 07:17 PM

Last for a few more opinions!

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Posted By: HardcoreB

Re: ADVANCING CAM TIMING 2-4* - 09/30/10 08:06 PM

Quote:

My 440's 266/266, 108 LSA cam is also installed on a 105 ICL. My CR is 10.8:1. My Dynamic 9.5" converter flashes to approx. 4500 from a 1800 launch off the foot. I've tested "a bunch" of different things and whittled my 60-ft. down to 1.45-1.46 on 275/60R15 DOT drag radials. Car & driver is 3750+ #s, so it's not a lightweight.

IMO, raise your CR some, get the heads ported, and spend some time tuning the effer. Leave the cam ICL where it is so you know what gains resulted from the CR & porting. Oh, maybe put some 1.6 intake rockers (intakes only) on to help use the improved high-lift flow of the ported heads.

Yes, you can loosen up the lash .004" from your normal setting to see if it "likes" a slightly shorter duration. Check w/ Dwayne or COMP on what the min / max lash for your cam's lobes are, since there is usually an acceptable range to run. My XX lobes are usually listed as running .020", but are OK running from .016-.024" (hot).

All out of opinions on this subject...


I agree with everything said here to a tee but, I doubt throwing a set of intake rockers at it is in the budget after the cyl. head improvements $$$. I think I kinda implied this in my first post too. (I'm just saying I'm not much of a 'post' flip-flopper.)
Posted By: Labratt

Re: ADVANCING CAM TIMING 2-4* - 09/30/10 09:36 PM

Thanks Sean! Hope the wedding turned out as planned this past week-end! I will be sending you a PM later today about a bon-fire get together at our place some time in October! As far as the X goes...Brad has the right idea as far as leaving the ICL where it's it,that way I'll know how much I picked up with the head work!Also..I already am running Crane ductile 1.6 rockers,intake and exhaust!
Hopefully,I have the clearance to up the CR to 11-11.5! That's gotta improve the torque some. I'm also wondering if my Edelbrock Performer RPM dual-plane would be better than the M-1 that's currently on it? With the ported heads,how much do you think the Peak HP RPM would be? Right now it's 6000rpm. Peak torque is at 5200,which I'd like to lower,without losing any torque! Converter flashes at 4500! Also,probably be a good idea to have both intakes port matched to finished CNC'd port configurations. Thanks again,Buddy!

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Posted By: HardcoreB

Re: ADVANCING CAM TIMING 2-4* - 10/01/10 05:46 PM

As many concur the changes you've outlined will net you a solid 10 sec. card with some tuning, no problamo. I'm sure most your ET gains will be in carb optimization and maybe something in sealing the scoop if not already/jetting etc... If you were going out again this year as suggested I'd move the cam timing to 102 or so...I'd bet your current timing is slightly higher than 105 if it was initially set there due to chain streach. I'll clear out some PM's again, I'm/we're looking forward to socializing.
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