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Re: Help solve the mystry, better flow numbers, same power?
[Re: gregsdart]
#1517182
10/16/13 04:40 PM
10/16/13 04:40 PM
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Joined: Jan 2003
Posts: 31,046
Oregon
AndyF
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Quote:
The motor dyno'd 847 hp at 7,000, 760 torque at 5700. The power seems to correlate well with the best ETs, 8.70s to 8.90s depending on tire type and DA, which on a good day is 1400 to 2000. The best on straight alky was 8.77 153 mph with radial 14.5 x 33 slicks. The big bias GoodYears helped traction and consistency, but cost a full .10 in ET. Changing from 5600 to 6500 stall actually picked up about .05 ET, but some of that may be related to the suspension not being optimized at the time. The car 60 fts better now, so maybe a tighter converter would improve ETs some.
Those heads will support quite a bit more power than 850 hp if you're willing to spend the money. All depends on what your goals are and what the budget is.
Do you know what your installed height is? You should be able to get 2.00 inch installed height which lets you run 0.850 net valve lift. If you put a 1.7 or 1.8 rocker arm on the intake you should be able to get to .850 lift without anyh trouble. The exhaust might work just fine with the 1.55 rockers that you already have.
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Re: Help solve the mystry, better flow numbers, same power?
[Re: AndyF]
#1517183
10/16/13 04:53 PM
10/16/13 04:53 PM
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Joined: Jan 2003
Posts: 5,486
SoCal
Brian Hafliger
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Quote:
Quote:
The motor dyno'd 847 hp at 7,000, 760 torque at 5700. The power seems to correlate well with the best ETs, 8.70s to 8.90s depending on tire type and DA, which on a good day is 1400 to 2000. The best on straight alky was 8.77 153 mph with radial 14.5 x 33 slicks. The big bias GoodYears helped traction and consistency, but cost a full .10 in ET. Changing from 5600 to 6500 stall actually picked up about .05 ET, but some of that may be related to the suspension not being optimized at the time. The car 60 fts better now, so maybe a tighter converter would improve ETs some.
Those heads will support quite a bit more power than 850 hp if you're willing to spend the money. All depends on what your goals are and what the budget is.
Do you know what your installed height is? You should be able to get 2.00 inch installed height which lets you run 0.850 net valve lift. If you put a 1.7 or 1.8 rocker arm on the intake you should be able to get to .850 lift without anyh trouble. The exhaust might work just fine with the 1.55 rockers that you already have.
Brian Hafliger
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Re: Help solve the mystry, better flow numbers, same power?
[Re: gregsdart]
#1517184
10/16/13 10:29 PM
10/16/13 10:29 PM
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Joined: Jan 2003
Posts: 14,504
So. Burlington, Vt.
fast68plymouth
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your post is, "more flow....same power"
did you dyno the motor before and after that stage of head developement(without other changes)?
when you're running 150+MPH......20-30hp can get lost if the car isnt 100%.
i guess what i'm saying is......do you really know what, if any, difference those last mods to the heads had on the power curve?
or are you trying to extrapolate that data from the time slip?
68 Satellite, 383 with stock 906’s, 3550lbs, 11.18@123
Dealer for Comp Cams/Indy Heads
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Re: Help solve the mystry, better flow numbers, same power?
[Re: fast68plymouth]
#1517185
10/16/13 10:41 PM
10/16/13 10:41 PM
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Joined: Jan 2003
Posts: 5,991
Anoka County, MN
Leigh
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I just want to comment, on how good it is to see, the most experienced and expansive minds on this board, posting on this topic. Seriously folks, appreciate it, it doesn't happen very often. I am saying thanks.
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Re: Help solve the mystry, better flow numbers, same power?
[Re: Brian Hafliger]
#1517186
10/16/13 10:44 PM
10/16/13 10:44 PM
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Joined: Jan 2003
Posts: 10,010
Frostbitefalls MN (Rocky&Bullw...
gregsdart
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currently I have Comp 947 springs in at 2.00. I can go up to 2.050, but will lose some of the 340 seat pressure, which makes me nervous. Comp 948 springs would solve that, but the seat pressure will be higher, 375 on the seat? Any cam that is more radical than I have I would think will want the same or more spring than I now have. Budget is going to be a serious consideration here, as I also believe I need to tighten the converter a touch due to the gains from M5, combined with the gains from a better cam profile. Is it most of you guys opinion that the power curve will stay at the same rpm, just more torque and hp?
I have to sit back for a bit and see just how much $$ I want to throw at this deal to make more power. At this point, lets say I want to budget for a cam, converter alteration, and maybe springs. If the lobes get more radical, maybe a spare set of lifters, but that would be the limit. The present cam is a Comp cut with a base circle for a .490 lobe, so to keep the pushrods the same I figure I don't dare go below the present base circle by more than .010 to .020? The lash adjusters are all within 1/2 turn of the rockers, or closer.
8..603 156 mph best, 2905 lbs 549, indy 572-13, alky
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Re: Help solve the mystry, better flow numbers, same power?
[Re: AndyF]
#1517188
10/16/13 11:42 PM
10/16/13 11:42 PM
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Frostbitefalls MN (Rocky&Bullw...
gregsdart
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Quote:
You are going to have a hard time getting the necessary lift with just 1.55 rocker arms. Rather than a new cam, can you run 1.70 intake rocker arms with your existing cam? That gets you to .850 gross lift on the intake side, speeds up the valve action and gets you a bunch more area under the curve. You would need to check with the cam grinder to see if the lobe works with the higher ratio.
Great point. I do have the other cam on the shelf, the RR735 which Isky says will tolerate a 1.70 rocker, but no more. That will give me gross .833 intake lift, .776 exhaust, with lash of .026 and .028. Duration is 280/288/110lsa. I am not sure of the .200 duration.
I would also like to thank everyone that has contributed to this post. This is the kind of input that got me this far (from 10.20s to 8.70s!) and it is greatly appreciated.
Even if my budget doesn't allow me to go as far as is possible, I am sure there is one or more guys out there piling up parts similar and looking for the most they can get out of the $$ they have.
8..603 156 mph best, 2905 lbs 549, indy 572-13, alky
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Re: Help solve the mystry, better flow numbers, same power?
[Re: fast68plymouth]
#1517189
10/17/13 09:10 PM
10/17/13 09:10 PM
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Frostbitefalls MN (Rocky&Bullw...
gregsdart
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Quote:
your post is, "more flow....same power"
did you dyno the motor before and after that stage of head developement(without other changes)?
when you're running 150+MPH......20-30hp can get lost if the car isnt 100%.
i guess what i'm saying is......do you really know what, if any, difference those last mods to the heads had on the power curve?
or are you trying to extrapolate that data from the time slip?
Dwayne, good to see you here! I never did re dyno the motor, just bolted it together and kept an eye on ETs. There was no gain at all. Same track, good record keeping,all the stats that will affect ET. The car is very consistant, so the only thing I can think of that might upset the comparison would be the lose converter? (6500 rpm flash) I tried the same rpm, 300 more rpm, no change. I recall adding four percent fuel for the first couple of passes. The ET was off, so I went back to the old tuneup. ET came right back to where it was before the cam change.
Last edited by gregsdart; 10/17/13 09:14 PM.
8..603 156 mph best, 2905 lbs 549, indy 572-13, alky
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Re: Help solve the mystry, better flow numbers, same power?
[Re: gregsdart]
#1517190
10/21/13 10:06 PM
10/21/13 10:06 PM
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Joined: Jan 2003
Posts: 14,504
So. Burlington, Vt.
fast68plymouth
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Greg, here's my  without knowing all the details about that last head mod, i'm going to guess that perhaps the heads responded disproportionately well to the install of the bigger intake valve, and that not a lot of additional material was removed upstream of the valve seat. my feeling is that you're basically maxing out the available port cross section on the running motor, especially with the alky. you need to run about twice as much alky as gas, and that additional fuel takes up a lot of space in the intake tract, which is going to lower the rpm at which terminal velocity is reached. my gut feeling is that a more agressive valve action will allow the curve to look better above peak power, but i think its going to be a challenge to significantly raise the terminal rpm. i dont feel its going to be that easy to make noticably more TQ than you have now, so then the only way to make a big change in HP is to make the TQ hang on better beyond its peak.
68 Satellite, 383 with stock 906’s, 3550lbs, 11.18@123
Dealer for Comp Cams/Indy Heads
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Re: Help solve the mystry, better flow numbers, same power?
[Re: fast68plymouth]
#1517191
10/21/13 11:44 PM
10/21/13 11:44 PM
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Joined: Jun 2007
Posts: 2,646
Plymouth Meeting, PA
bigtimeauto
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Quote:
Greg, here's my
without knowing all the details about that last head mod, i'm going to guess that perhaps the heads responded disproportionately well to the install of the bigger intake valve, and that not a lot of additional material was removed upstream of the valve seat.
my feeling is that you're basically maxing out the available port cross section on the running motor, especially with the alky.
you need to run about twice as much alky as gas, and that additional fuel takes up a lot of space in the intake tract, which is going to lower the rpm at which terminal velocity is reached.
my gut feeling is that a more agressive valve action will allow the curve to look better above peak power, but i think its going to be a challenge to significantly raise the terminal rpm.
i dont feel its going to be that easy to make noticably more TQ than you have now, so then the only way to make a big change in HP is to make the TQ hang on better beyond its peak.
exactly.
BB, TT5,Procharged 3300lb Street Car 4.79/154
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Re: Help solve the mystry, better flow numbers, same power?
[Re: gregsdart]
#1517194
10/22/13 09:02 PM
10/22/13 09:02 PM
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Joined: Jan 2004
Posts: 903
Saskatchewan, Canada
cudabin
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Saskatchewan, Canada
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Less flow at 382cfm from my -1 heads, but it pulls hard right to 8,000rpm going through the traps with this cam: 1.7 ratio Jesel Pro individual shaft rockers, 7/16" .165" wall Trend's w/ push rod oiling. Custom LSM roller 288/304 dur @ .050", .875"/.867" lift, 114 lsa installed at 112 cl. 68 degrees overlap, 4/7 swap, 54mm core. Also Alky with single terminator. PSI double springs and titanium 2.25" intakes. I think more cam could really help you Greg... Cheers, Arnie
67 Cuda 8.48@ 158.7 mph 1.18 60' 2,600 DA(so far...)
70 Super Bee 440 Six Pack 4-speed. 13.2 @ 104 Stock exhaust/Street tires.
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Re: Help solve the mystry, better flow numbers, same power?
[Re: cudabin]
#1517195
10/22/13 10:14 PM
10/22/13 10:14 PM
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Joined: Jan 2003
Posts: 5,486
SoCal
Brian Hafliger
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Greg, have you run your specs through pipemax just to see what it comes up with?
Brian Hafliger
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Re: Help solve the mystry, better flow numbers, same power?
[Re: Brian Hafliger]
#1517196
10/22/13 10:41 PM
10/22/13 10:41 PM
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Joined: Jan 2003
Posts: 10,010
Frostbitefalls MN (Rocky&Bullw...
gregsdart
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I just bought the pipemax program, will mess around with it. Dwayne, I think I get what you are saying, and pretty much everybody else thinks it needs more of something in the cam department. One program (dynomation) calls for less duration,( a LOT less on the exhaust) more lift on both sides. To try and stay inside some sort of budget, I am going to try the following, funds permitting. Install the original RR735 Isky cam. 280/288/110 Put it in at 106. That raises the dynamic compression from 11.00 to about 11.5 Going from the present cam this cuts overlap by 2 degrees, leaves the exhaust closed for 5 more, and closes the intake 5 earlier. Lift will be up .057 intake, .022 exhaust. 1.7 rockers on the intake side for .831 lift gross. Comp 948 springs on the intake side for 366 lbs on the seat. 1.55 on the exhuast for .706 lift. Tighten the converter(from 6500/6600 to 5800) to pull the motor down where it will run best with this setup. I have to think that the shorter cam will swing the power back down enough to make it 60 ft better, and ET overall better. I may not see a lot based on drag sim programs, the best run with no wind speed was high for the ET at 153 mph. I also plan to look for a bit lighter rear tire. Those 2079s are old, and HEAVY! what do you all think? It may not be near what I could get, but there is a $$ limit on speed; everybody knows, speed costs. So, between that and the M5, I hope to see some 8.60s in good air, oh , and go on a diet; it would be nice to see some gain out of this somewhere  If this combo fails to produce, then the next move will be to have a cam cut for a better match to the motor. One last detail is collectors, or lack there of. I have a very tight exit area, and they are extremely short, like 4 or 5 inch of round collector. The program said longer. Any thoughts?
Last edited by gregsdart; 10/22/13 10:44 PM.
8..603 156 mph best, 2905 lbs 549, indy 572-13, alky
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Re: Help solve the mystry, better flow numbers, same power?
[Re: gregsdart]
#1517197
10/22/13 10:50 PM
10/22/13 10:50 PM
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Joined: Jan 2003
Posts: 5,486
SoCal
Brian Hafliger
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According to Pipemax, your curtain area limited to 6000rpm!
You'll need at least .850 lift at the valve, so figure closer to .890 gross.
Race gas, change cam, and then someday go to a tunnel ram/sheet intake with 2 carbs should all net more e.t. and mph.
And yes your collectors are way too short! But, I've seen some engines not respond to proper length collectors meaning there's problem somewhere else. I would start at 12-14 inches of collector, even if you have to put a bend in them.
Is this combo 4.500 bore and 4.15 stroke?
Brian Hafliger
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Re: Help solve the mystry, better flow numbers, same power?
[Re: Brian Hafliger]
#1517198
10/22/13 10:52 PM
10/22/13 10:52 PM
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Brian Hafliger
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I don't know how big the runners are in the plenum of the 3X intake, but I just measured a -3 intake today and they are right at 4" give or take. So if the 3X is larger, it might be too large? Did I mention I don't like alky on large high rpm N.A. engines....
Brian Hafliger
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Re: Help solve the mystry, better flow numbers, same power?
[Re: Brian Hafliger]
#1517199
10/22/13 10:59 PM
10/22/13 10:59 PM
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Joined: Jan 2003
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Frostbitefalls MN (Rocky&Bullw...
gregsdart
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Bore 4.5 stroke 4.15
The intake ports are as big as they can go, done by one of the best. But they still are too small I know. The head work was just put in the bigger valves, and blend to the existing port.
Here is a dyno sheet from the original setup, with the RR735 cam, and 2 inch x 40 inch Dyno headers. Mine couldn't be hooked to their system. Changes since have been to add a much better oil pan, fine tune the fuel curve up top, and later, more cam, with no gain there.
As far as the collectors, that will take major surgery, and If I go that far, I may as well upgrade to a step header. The collector has to move a lot to be able to be extended.
Last edited by gregsdart; 10/22/13 11:06 PM.
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Re: Help solve the mystry, better flow numbers, same power?
[Re: gregsdart]
#1517200
10/22/13 11:03 PM
10/22/13 11:03 PM
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Joined: Jan 2003
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SoCal
Brian Hafliger
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Look at how the power climbs until around the 6000rpm range...it comes to a screeching halt!
If you want your heads to work better, run race gas. Then get some good rockers, 1.7 at least, then change the cam. Is the carb a 1050 or? Spacer?
I'll bet you can pick up a lot with these changes.
Brian Hafliger
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Re: Help solve the mystry, better flow numbers, same power?
[Re: Brian Hafliger]
#1517201
10/22/13 11:10 PM
10/22/13 11:10 PM
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Joined: Jan 2003
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SoCal
Brian Hafliger
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Just read your info again...I think you might have too much compression. I wonder if there's room for some chamber work and less dome?
I see your running injection with the alky.
A 1250 carb and a 1.5" tapered Wilson spacer with some intake mods might make more power too once the cam and fuel are taken care of.
Ofcourse, there are just my opinions!! But I see this a lot so I'm fairly confident in what I'm telling you will work.
Good luck Greg!
Brian
Brian Hafliger
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