Tips Tuning Stroker

I got to the track this weekend, car ran pretty good but only MPHd at 116 MPH. I thought that was weaker than it should have been. ET was 11.71.

Race weight is 4220.

Running a 4 speed and 3.54 gear with 28" drag radials, so it really wasn't strong off the line, but thought it would be producing more steam at the big end.

So far, this is where I am.

526 CI 440 source kit, 10.1 CR, quench at .046

Mopar 337 intake polished with ports matched, 850 Mighty Demon annular

Trick Flow 240s, Trick flow heads, ported 246 cc runners
INT
1. 99
2. 170
3. 243
4. 306
5. 340
6. 352
7. 370
Doug's D452 headers, 2" primaries, 3 1/2" collector I ran the 3" TTI exhaust connected.

Cam is 260/264 @ 50, .616/.620 108 in at 104
https://www.summitracing.com/parts/hrs-720152-08/overview/

Mancini 1.6 rockers

I am running the lash @ .014 instead of .018, lots quieter.

Running at 36 degrees total, in by 2800 rpm

Car feels like it pulls strong to 7,000 rpm after it gets rolling.

Checked vacuum running through the gears, even @ 7000 rpms, the gauge does not come off zero.

AFR stays right around low 13s down the track.

Compression is 175 across the cylinders.

Did I make a bad choice on the cam? The people I checked with before building gave it a thumbs up.

Wallace calculator says a little better than 500hp,what should I try to make more power at this point.

Although I don't have any dyno simulator, I was thinking closer to 600 hp than 500.

I think the cam is too big for your car and gears. That is probably why your cranking compression is a little low although there could be a lot of reasons for a low cranking compression.

My old 466 ran a 236 @ 050 solid flat tappet with ported RPM heads and cranking compression was 200 psi. That engine made 550 on the dyno and 475 rwhp. I tried bigger cams in that engine but they lost toque down low and didn't make up for it at the top end.

If it was my car I'd double check everything before pulling the engine apart, but if it all checks out I'd go about 10 degrees smaller on the cam and see what happens.

In the short term you can tweak the timing a little bit. Maybe add some jet, pull some timing out and stuff like that. Sounds like you have a wideband in the car so that helps to sort stuff out. Keep an eye on the plugs also.

Are you sure the intake port match is good? I had to build my own valley plate with batwing gasket holders to get the intake gaskets lined up properly with the 240 heads.

You can find out real fast if the cam is too big. Open up the lash to .018-.020 and run it again.

I think you did pretty good. Take 1000 pounds off that car and its in the 10's easily without much gear or compression. Pretty impressive.
Cam in my little 360 is 260@50 as well and its just a touch over 10 to 1 itself. At over 500 inches hard to believe your cam is " too big"
How do you launch the car and what rpm is it crossing the stripe at?

What where your sixty foot times?

4220 is a lot on weight to get moving, especially with a stock gear. I can see a lot of breakage in your future. At 3200 lbs.my .Barracuda 440 source pump gas 505 runs 10.30 at 130 with 4.56 gears . So if the calculation of .1 tenth per 100 pound loss your into the tens. My advice is to loose weight, change the gear to maybe a 4.10 if this is street / strip car more gear if strip only.

Lots of cam and head flow, but perhaps not enough carburetor to feed the RPMs they want. With a heavy car, you may have been better off focusing on midrange torque than top end hp (??). With that said, Don’t let yourself get disappointed the first time out. It takes trial and error to find what makes each combo ET. That’s a lot of weight you’re pushing; you’re really going to have to have the chassis work well to get 4220 to ET effectively. My car goes 3820, and I thought it was a load.

I'll play with the timing a little bit and maybe give it some more jet.

The intake and heads both looked good on the MW sized gasket, although I was sucking some oil past the gasket, and had to use some motoseal to get it to seal up.

I read a post you made a while back, where a 337 intake kept making power over 7k. I was trying to use that as a basis to match the top end. I probably need to get a Dyno simulation program to play with. Thanks for your thoughts!

I didn't realize it would affect duration, I'll try it, thanks!

Yea I spoke to several people who agreed they did not think it was too much.

There is no way I'm going to drop 1000 pounds, but, I plan on some fiberglass bumpers and hood.

I only got 4 runs in, the best time was launching at 3500, shifting at 7, and shifting into 4th just before the stripe.
I think I was at 5100 rpms or close.

Thanks for the reply!

Hi Cab. They were 1.76ish
I can do better with some 26 inch tires and practice though.

Here's a video, you can see the rear springs working

https://www.youtube.com/watch?v=_cBwV3gCAck

I already have been looking around for 4.10s. The clutch wasn't liking the 4500 rpm launch much. Thanks for the reply!

I love your car.
My car was a bit lighter before the sub frame connectors and full exhaust. It weighs 3960 now.

Thanks for the post!

Drag radials and a 4 speed probably don't get along very well Buy another set of bias ply tires that are designed for a manual trans. and work on the 60 ft. times
Once you get the 60 Fts. in the mid to low 1.50 the MPH will pickup also due to getting the trans into high gear sooner, don't short shift it make it hook up better, so the motor will have longer to pickup MPH in high gear.

using wallace with your weight/tyre/gear and 540hp I get>
60 Foot E.T. : 1.61
1/8 Mile E.T. : 7.29
1/8 Mile Trap Speed : 93.20
1/4 Mile E.T. : 11.56
1/4 Mile Trap Speed : 116
1/4 Mile Trap RPM : 4,928
with 4.10's its 5700 trap, better...4.3's>6000, I reckon there's more in there hp wise, just got to unleash it at the right time.

As an example, I was running 13.31@101 in street/strip mode with 3.55's/26" slick and a 3500stall combo. I added, 4.30's/28" tyre, 4200stall+ better cam/carb/hdrs and went 12.39@108.6, mph shows +65hp in the motor which is not a second improvement in ET, its how/when its delivered.

With that big a cam, a 4.10 gear will help out a lot.

I think you need more carb, among the other things suggested. The various carb size calcs say 900'ish for your cubes at 85% VE, and you're probably up in the mid 90's. S/F....Ken M

Other than gear and weight, IIRC. The mighty demon CFM number is wet flow number. So in comparison to others it is a "bigger" 850.

I am surprised at how many of you w/BB guys even consider a 4150 when a 1050 Dommy on this motor would wake it up big time.........an 850 BARELY belongs on a warmed small-block...........

Thanks for all the replies,

Cab-The drag radials are dead hooking at this point, maybe a turn. They are spinning as much hitting second gear, once the engine is building steam.
60s in the 1.5x area would be great!!!!

SG Cuda - yup they sure would. Going from 28" tires to 26" should reduce the effective gear ratio to 3.8, so that will help some

EchosSixMike- I dont know about the carb. AndyF said he seen 20-30 hp going to a dominator because of a superior spray pattern. My carb isn't making any vacuum even at 7k.

FurryStump- I was told by a local carb shop he estimates it close to 1080 cfm

Dom- Yea it is in future plans. It will require removing the hood for clearance. That, and probably an electric booster pump?

I am going back out to TNT with 26" tires, without the hood, a 2" spacer, and play with timing and jetting.

I also just got a FBO box and coil to replace the orange box. I was getting some breakup over 6k.

Hopefully the driver will be better.

I'm under the impression that all of the Mopar orange ECU have a built in rev limiter of 6000 RPM in them, all of them

I assume rear jet extensions, what pump is on it now?

Cab, I have never read that "rev limiter" thing. I bought my orange DC box in 1984. I think it has more to do with a slightly faulty memory and the Direct Connection/MP catalog wording that says it's best used up to 6000rpm. I don't think there's enough electronics in the box to include a rev limiter, unless the transistor speed isn't fast enough for more than 6000rpm.

OP, there are two reasons why your cam is acting like it's too big. First of all you closed up the lash and that has the effect of increasing duration. Then you are running 1.6 rockers and they have the effect of increasing duration. BTW your lifts with the 1.6 rockers are 0.657 and 0.661.

Also, your rear gear is really slowing you down off the line. Those are highway gears with the big tires. I think you need 4.30s. Now it seems you're crossing the line at 5000 rpm.

AndyF was right, the cam is too big for the car and gears. 4200+ lb and 3.54s don't work with that cam. If you want to keep the car and gears the way they are, then the cam has to change.
If you change the gears and stop making the cam act larger than its measurements, the cam can stay. I'd run the test with 0.022" lash. Most sources say that 0.004 more lash won't hurt and the stock lash is 0.018. I'd be in favor of keeping the cam as you've got it broken in.

One more thing: If you are showing no vacuum under the carb as you cross the line, the carb doesn't need to be any larger. As you change the gearing and start going faster, it may happen that you need more carb. But that's for later.

R.

Cab- I never had it break up on the street, one of my runs though it acted like it was a rev limiter. That's ok though, I wanted the rev limiter in the FBO box.

FurryStump- I'm running a Carter Mechanical 120 GPH and a full 3/8 line and sending unit. No jet extensions.

https://www.ebay.com/itm/Carter-Muscle-Car-Mech-Fuel-Pump-Dodge-BB-413-440-120-GPH-5-5-to-6-5-PSI-M3672/331399778792?epid=76996104&hash=item4d28f751e8:g:0Y8AAOSwLVZVy4wY&vxp=mtr

dogdays- Wow lots of helpful info

I wasn't thinking that increasing the lash would increase the duration. I can sure open the lash up.
When I was looking at cams, I wanted to get a high lift to take advantage of the .700 lift number the intake would flow.

I had 26" tires on the car but just put on the 28s. You can tell the difference. I got the 28s because I was originally planning to drive the car about 800 miles to go to the Moonshine Fest north of Atlanta, but will throw the 26s back on.

I'll be pulling the rear seat and wiper motor and hood. That should drop me back to 4000 lbs race weight.

I can't wait to see what the improvements net me.

Thanks again for all the help.

Based on you mph, it does seem that you need to find some missing hp, IMO.

Even though your A/F looks okay going down the track, I would still put a pressure gauge on it to verify it.

If the A/F is right, I would try fattening it up until it loses mph.

I also like the idea of opening the lash. I would not be afraid of 0.024 for a trial.

Yea, that is kinda why I started this thread, seems like I'm missing some power.

What kind of pressure gauge do you mean? fuel pressure?

The car has a clutch fan with a mechanical water pump, so that's like what, 30ish hp?

I have no idea what an orange box pulling 8* of timing might drop hp.

Kept my 3" exhaust corked.

I took off the air cleaner, using NGK heat range 6 plugs.
The gas I used was 90 octane with a bottle of booster.

I was thinking the engine should be up closer to 600 than 500 hp.

Maybe it is ,and it just isn't coming on fast enough, like Andy said, to make up for the big bog off the line.

According to Wallace, Im 525-540 HP

Opening up the lash fools the motor into thinking that the cams is smaller, tightening it does the opposite
Test, test, test and then test some more until your happy with the car

Yes, fuel pressure.

IMO, this is the time to kinda let go of trying to reconcile all the calculator hp numbers and "what should it be" engine dyno #s. Otherwise you'll make yourself crazy trying to rationalize stuff.

I'm simply comparing mine to yours.

If you are blowing 175 on the gauge, you'll be fine, you just need to find it. Could be in the tune or a few small things. You'll find it.

Not my orange box. I shift about 6200 and trap about 6400 and it never misses a beat with my orange ECU. And when we had it on my sons Dart with his 400 he would push it over 6500 and still it worked good. He ran no faster when we put MSD on his car. Ron

You need some gear with the 4 speed to get it off the line. Are you shifting at 7g? If you are that’s not helping et either. That thing should probably be shifted around 6-6200 with standard port window.

Hello,
I didn't get many runs down but it has TF heads opened up to MW ports with a matched 337 intake.
I wish I knew where the HP/TQ peak was.

Its funny to hear that and I mean it in a nice way. Thats because my brother always used to ask me what I shift at as years ago we raced each others cars. And he would get mad at me sometimes as I told him I dont look at the tach when I shift. We had 4-speed cars when we first started racing. I am just the kind of hotrodder that shifts by the feel of how the car is pulling to me. To me as soon as I feel like its peaking I shift. I shift my 63 the same way as I just dont use the tach much when I shift. And I must get it pretty good as I ran 10.76 three passes in a row before and never looked at the tach when shifting. My brother always uses the tach when he shifts but back when we had 340 four speed cars I was always faster then him in the stick cars shifting by how the eng feels. I dont know why but I have always felt I can jump in any car and with just a few passes know about where it feels right to shift. I am sure other hotrodders must feel the same way. Course for wanting to be very consisdent when bracket racing it has to help shifting at the same rpm every run. Ron

Need bigger carb, and in the video looks like your front end is tight.

if your dead hooking on radials what RPM are you launching at?
Dead hooking that car may end up breaking a lot of drive line parts in time
Stick shift cars are full of drive train eating demons, you have to feed them AKA, you can feed them tires or clutches or U joints or axles or so on and on

The funny thing was, I couldn't hear my car because I had a full exhaust. The guys beside me were running open headers.

Car feels like it's still pulling strong past 7k, but, I'm putting my FBO box with the 7k limiter in to keep the engine together for a while.

I'm going to try next time out making the changes you guys have suggested, can't wait!

I keep getting conflicting advise on the carb. It doesn't pull a vacuum even to redline, although there's no doubt a Dominator would make more power.

Good call on my KYB gas charged shocks.

The tires turn maybe a time or two, just enough to make them smoke a tiny bit.

I tried launching at 3000,3500,and 4500 rpm.
At 4500 I could smell the clutch (McLeod RST twin disc).

Going out next time with all the changes you guys suggested, smaller tires, increased valve lash, about 200lbs less weight, so I guess the whole testing process needs to start over to see where it's at.

FWIW: I’ve found the most important factor in moving a big heavy car is effectively utilizing your “torque peak”. For instance, my car FEELS like it’s pulling through 6700. But when I short shift it at 6200, car goes faster. It isn’t always whether or not it’s pulling at the upper RPM, it’s balancing that pull against the torque you’re shifting back into. In order to use your torque effectively, you want to land right on your torque peak with your shift, if you land beyond it, you may be losing ET by letting the engine wind too long even though it still is making power at that upper RPM.

As I see it....the only way your going to get the best out of the car with the hp you have is if you can trap at nearer 7k, as you say it still pulls well there. Best way of doing that is to use the 28" tyre with a 4.56 gear, but thats probably not going to happen, so the only other way it can be done is with say a 29" tyre and try and run it out in 3rd. A 26" tyre will still only see you trapping at around 5400, not enough, and I don't think lash changes etc, will do much to help hp but it'll be fun trying I guess......my2c's

Sorry I missed this response-
I actually have a MW ports,but you are correct, it seems to go as fast or faster shifting 65-6700.

Just to review-
My 526 has ported TF and 337 intake, 260/266 @ 50 cam, 2" headers through a 3" exhaust.I have 3.54s and a 4 speed.

My first time out at 4200 lbs and 28" tires it was almost dead hooking, and bogging the engine.
My 60 was 1.79 and 11.71.

Since talking to some guys on here I did the following

Advanced the 108 ICL cam, it's now in at 101.

Opened the lash to .020

Went to FBO box

Installed jet extensions

Installed a fuel pressure gauge- it was losing fuel pressure, top of 3rd gear was almost 1 psi, even though it didn't seems to nose over

Got some 26" bias ply slicks, huge improvement in SLR and grip

Went to a Carter hemi type FP, it works good when it works, which is about half the time, it just loses pressure off idle or driving normal.

I ordered a FG hood with a Hemi scoop from Sled city, not sure when it will be done, but that will cut about 100 lbs. I would like to try a carb spacer

One thing I noticed, the low end improved dramatically with the cam advance.

I used a larger wheel than originally, the cam was actually installed at 105. I was hesitant to go another 4, but boy was it a good move.

My cranking compression jumped from 175 to 185, engine used to buck at low throttle just cruising around anything under 2000, now 1800 is no problem.

Full throttle it still pulls hard to 7k.

The time slips will tell, but there will be improvement, it pulls harder than before.

Thank you all you guys for your help. Every bit of advise given made the car just a little bit faster.

If you are running with the exhaust hooked up, it might be strangling the motor. I would get a pair of 18 inch extensions for the headers and try running open exhaust. The extensions alone on an open pair of headers were worth a tenth plus on a couple of my cars.

11.50 should be your goal! Any faster than that will require belts & bar

I might try opening up the headers.
My wide band is back about 18 inches in the exhaust so I was wanting to see what the AFR was, but I'm happy with that.

It was annoying not to hear your own car, when the guy in the next lane is running open, which is most everybody.

Your in control of your car on the starting line, don't leave on the last light Give the other side 3 to 8 second head start so you can hear your own car Don't leave until you want to

YES 4.1 gears and a Dominator carb

Or one time at 10.99 would be cool too!!

I know, just not in the budget this year

Very interesting thread. I'm going to have to watch this one. I have less cubes, less weight, less cam, but a 4-speed and a 3.54 gear. I was going to put a 30" tall tire on it, but this is making me think twice. Unless I go to a 4.10 or a 4.30. I think I can live with the RPM at 75 MPH with either gear and the tall tire.
Good luck. I hope you can hit your goal. If you have one.

Seems like guys are all the time finding out a gear change doesn’t do a thing. Small changes in et that could even be weather related. Same thing with cross overs in the exhaust or lack thereof.

You've made a bunch of changes, but the fuel pressure is what was hurting you. What was your mph?, 118-ish?

The opening of the lash is probably what cleaned up the low rpm more than anything. You probably took 8° to 10° out of the overlap seat timing. Don't be afraid to go to 0.024" on the lash for a trial. It might not lose anything at the track, but will sharpen the motor up even more down low on the street.

I think it'll go 10s at 125 out the back door. You might want to go back to the taller tire when its all sauce and done.

Good luck.