I am currently running a 496 low deck stroker in my 65 Belvedere, it runs 11.13 @ 125 in full street trim and with a 4 speed.

I was wondering if i could could a little better cam for my setup because it seems to lose power up top according to the dyno sheet, current setup:

4.25 Stroke
4.31 Bore
Indy 440EZ heads hand ported, flow 354 @ .500
Indy Low Deck Single Plane
1050 Dominator
12.7 : 1 compression
TTI 2 inch primary headers with no exhaust
4 speed with a 3.91 gear

Current cam is a comp solid roller with these specs:

.660 lift on the exhaust
.655 on the intake
282 duration @ .050 on the exhaust
281 on th eintake
110 LSA
and it is currently advanced 2 degrees and has been degreed for the motor.

anyone????

I really dont think its your cam ... might be a fuel
supply problem
How many rev's do you turn

i shift it at 7000

To me that cam should pull more rev than you take it to
but its a little short on lift... but it pretty well
matches your head flow.... have you checked your fuel
volume (flow)

i have not checked the fuel volume, but the motor is not starved for fuel, it run a very consistent color on the plugs and typically never had a problem running its best, it just seems on the dyno graph that it may be able to hold more power a little longer with a better cam combo.

What kind of trap rpm are you seeing? What does the car weigh? IMO with that 3.91 gear you might do better with a bit less duration.

to the best of my knowledge it goes thorugh the trap at around 6100, but i was thinking it could use a steeper gear, how much less duration would you think would suffice??

I have to agree with Mr P body on this one. Something is wrong with the car and it's not your cam. You made 572 hp at the wheels and it's only running 125 mph at the stripe? Something is holding it back...fuel system, weak ignition (good grounds?), clutch issues, etc. That's a lot of motor to be running those ET's and speeds. I'd go over the car real good and make it work with what you currently have before I tore into the engine looking for more power. CHIP

its full weight though and not a drag car. I drive it on the street.

The things you listed that would be holding it back have all been accounted for. It has a good ground it has a full MSD ignition, distributor, it has a sumped tank with an aeromotive 145gph pump -8 line all the way forward to a magnafuel regulator and a pretty decent 1050 dominator.

Full weight street car or not, that car should be running mid 10s as it sits. Or atleast running more MPH than it is.
I'd hate to see you tear into the motor and spend money only to find out that it doesn't help your situation. CHIP

ok so what kind of things should i test or look for while i try and diagnose this problem.

I agree w/others here. However 125 mph does put you in the 10`s but unless you shift like Landy or Sox, it seems to me it`s gonna be tough to get a smokin et. I went 9.98 @ 3150 lbs w/495 hp and torque at the tires.

it went 11.13, 11.14, and 11.15, then i launched and shifted the [Edited by Moparts - Family Friendly Site - Keep it clean] out of it and went 2 tenths faster through the 1/8 mile then as i shifted into 4th it slipped the clutch. Ended up going 11.14 at 118, and it normally traps 124-125 every time. So i think it has the potential to go 10's it just needs more tuning and some seat time, plus it was only a 1.67 short time.

Get those 60`s in the 1.4`s and you`re there.

i bet, but with a stock suspension car and a 4speed i don think 1.4's are too close

Do a compression test and also a leak down test on the motor to make sure you don't have any problems internally. Flow the fuel system to make sure it is flowing what it should. Double check ignition timing. etc.

What's the elevation at your track? How's the air quality there? If the air down there is pretty bad then that may account for your times and MPH being slower than I think they should be.

For comparison...I had a stock stroke .030" over 440 in my car, weighed in at 3700#, single dominator on a Team G intake, OUT OF THE BOX Indy SR heads, 262/268 at fifty solid roller, 14.5:1 compression...it was a street driven setup with mufflers on race gas. 727 w/ 5k stall, 4.10s and 28x10.5 DOT tires. Ran 10.40s at 129 mph.

It may be a combination of bad air and the fact that your car is a 4 speed that's throwing me off. CHIP

The air quality up here in Ohio isnt too bad, its pretty mild and not too humid.

Your setup had almost a point more compression, and those SR's are a way better head than what i run. But still i agree with you that i should be close to 130 mph with this setup. I really think it could use a gear change and maybe some more timing. As of right now it will run 113 mph at limiter in 3rd and it will go through the 1/8 mile in third at only 102 so a steeper gear may do the trick. And also i only have the timing at 30 degrees total because i didnt know how far the 110 would allow for.

But i really appreciate all the info so keep it coming.

If you're only running 30* of timing, that's a lot of where you hp has gone. Set the timing around 36* and I'm sure it will pick up. No worries about timing at 36*-38* with 110 octane race gas.

i will probably do a compression test just to be sure and i may take it back to the dyno and try out some more timing.

What clutch are you running, what rpm do you launch at? Going through the traps,...what rpm are you at?

LOL, didn't realize you're in Ohio. I was thinking maybe you were in Lima, Peru.

The SRs I had are not as good as what you have. They flow less than 300 cfm out the box (early castings), you said your heads flow 350+. I did have more compression, but you have 40 more cubic inches (1/2" more stroke). I'm not saying my combo ran this much better than yours and trying to make anyone feel bad, just giving you something to compare it too since they have some similarities.
You can't really compare dynos, but that motor in my car put 508 hp and about 460 ft. lbs. to the rear wheels on the local DynoJet chassis dyno.

I agree with the timing, 30 degrees is too low. You need to be around 36 degrees. CHIP

I run a Ram clutch, launch at 4700, and I don't really know where I trap, but I think iTs around 6200.

And defiantly no hard feelings I appreciate all the help I can get.

Slipper clutch or are you letting the tires spin on the line?

i was slipping the clutch, but if i get another chance to go to the track before it closes i am going to try and be more aggressive.

My thought was since it was a heavy street car a bit more torque would help the car accelerate.I would have limited the cam duration to about 276@.050.The installed cam is fine if the engine can stay in the sweet spot.I The timing should be 34-35 degrees and that will pick the car up alot. Depending on the tires a 4.10-.4.30 would be optimal.I think the others will agree a tall as possible tire is a good idea also.There is enough h.p. to run low 10's if everything is right but I am bit bit leery of the torque output.

it has no problem staying up in the revs, and i run a 28x10.5 goodyear slick. I really think some timing, seat time, and a gear would make my car run like it should.

Since you are running bias ply slicks, I would experiment and try letting the clutch out as fast as your leg will work. Adjust tire pressure / shocks and Launch RPM to get about 1 - 3 tire revolutions before the tires stop spinning.

That keeps the engine from bogging, and results in very good (not best) 60' times and tends not to break anything. This is what a lot of us street car guys do. Unless you run a specific slipper type of clutch, I wouldn't be letting the clutch out slowly, you'll just wear it out quick.

On the top end, look for fuel delivery. I had just run 120mph and the next two runs were around 113mph. Based on my LM-1 going lean in 3rd and 4th gear, I found out that the fuel pump / regulator were going away and not delivering enough fuel and causing it to go way lean on the top end.

I will try that launch technique, the fueling issue though i really dont see it as a problem. The car never loses any MPH, it always goes 123-125. And my fuel pressure stays consistent down the track so i will double check but i think i can mark that off of the list.

I may try and put the cam at 0 or 2* retarded rather than 2* advance and see what that does for me.