Would like to find 70 hp from my 582

[Malibu Vette]

I would like to run the 9.60 index class in my Chevelle. The problem is, it runs very consistant 9.90's at 137 to 138. The car weighs 3670 race weight, so I calculate that I need 70 more horsepower to run the number consistantly.

582 short deck
Dart Pro 1 345 CNC heads hand finished
Cam .810 .784 284 306 on a 112
T&D rockers
Dart intake match ported to heads
Jessel Belt Drive
14:1
6.385 rods
Pro systems carb built for the engine
Air fuels run 12.5 to 13:1 depending on the air
I run 36 degrees total advance.

What can be masaged to get there? I am thining cam and maby change to a Sniper or Super Victor intake.

What do you think?

[bigjoe1]

What brand of camshaft do you have now ?? How high do you rev up the engine now ??What size is your carburetor ??What does the converter stall ??It sounds like you run very well. It might not be easy to go faster.
JOE SHERMAN RACING ENGINES

[Fatman]

Has it been on an engine dyno? Results?

If not has it been well sorted?

Answering Joes questions will help. I think that motor could have a lot more potential. You often hear of 900+ hp from similar combinations.

Are the heads Darts 355 CNC Pro1 or a 345 Pro 1 that has been ported by somone else? Dominator carb?

[Malibu Vette]

What brand of camshaft do you have now ?? How high do you rev up the engine now ??What size is your carburetor ??What does the converter stall ??It sounds like you run very well. It might not be easy to go faster.
JOE SHERMAN RACING ENGINES

Joe, the cam is a Comp Cams. It does run pretty well and made 911 on the dyno 2 years ago when it was built. the carb is a 1200R from ProSystems. The converter is from Andre at Edge and stalls at 4300. I had him tighten it up to make the car leave more consistant on a marginal track. It consistantly 60's around 1.48 and went a best of 1.35 with the looser converter but it would not hook on a marginal track. Depending on if I am to believe my Autometer tach or my altronics O2 alert I shift at 7000 or 7500 and go through the lights at 6700 or 7200. the O2 alert reads 500 higher than the tach.

I was optimistically hoping someone would tell me the cam is all wrong and I can pick up 50 hp from a different manifold, but realistically I figured it will be little things.

My calculator shows it is making a little over 900 hp in the heat right now and it also shows I need to lose 200 lbs or make 70 more hp to run 9.60 consistantly. Any help will be appreciated.

[needforspeed66gt]

I think putting your car on a diet may be easier - that thing is a lead pig

I see more power out of the edelbrock manifolds, and good plenum work always shows some gains - but not near what you need.

[Troy Patterson]

What is a PS 1200R? How much does it flow? Is the Dart intake stock or has it been modified? Can you run two carbs? A hundred horsepower could be had. I saw 65 hp gain on a 408 making 545 hp with a manifold & carbs change - over a tuned Demon and Vic Jr. I can't take credit for that one, just saw the results. At your hp level, there is all the more potential.

Troy Patterson TMPCarbs.net TMP Carbs.net

[suicidal racing]

vaccum pump would help 2.

[Wolfplace]

vaccum pump would help 2.

=
That depends,,,

[Fatman]

i thought 900 HP would run much faster than 138 mph in 3670 lbs.

If it is making 900 then your gains would be small ones.

Re the Sniper intake, there have been some interesting results posted on this board that might be worth reading if you havent already.

[Troy Patterson]

i thought 900 HP would run much faster than 138 mph in 3670 lbs.

If it is making 900 then your gains would be small ones.

That's not my experience.

Troy Patteson TMPCarbs.net TMP Carbs

[Fatman]

i thought 900 HP would run much faster than 138 mph in 3670 lbs.

If it is making 900 then your gains would be small ones.

That's not my experience.

Troy Patteson TMPCarbs.net TMP Carbs

About the small gains or the mph?

[Shrinker]

hello; Just a quickie, We run a cam the same size as that in a 412 cube SBC and it start to wind on the power at 8800 rpm. Thats a lot different to your rev range. Could your cam be too big for the range your using?

[Troy Patterson]

i thought 900 HP would run much faster than 138 mph in 3670 lbs.

If it is making 900 then your gains would be small ones.

That's not my experience.

Troy Patteson TMPCarbs.net TMP Carbs

About the small gains or the mph?

The small gains.

Troy Patterson TMPCarb.net TMP Carbs

[UDHarold]

With such a short rod/stroke ratio (1.459:1!!) I think a 112 LSA is pretty tight.
As well as taking out some weight, I would recommend a cam with 319/327 at .020, 288/296 at .050, 209/215 at .200, .825".775" gross valve lift, .800"/.750" net valve lift, and either 114 or 116 LSA(115 if you aren't sure!). The wider LSAs will have a much smoother torque curve and be easier to hook up.
The gross vavle lift is with 1.7s, and I have run these cams with 1.85s/1.9s. The closing ramps have the same seating rates as my 24-hour cams for road-racing.

Make sure you have a good high-volume electric fuel pump and 1/2", #8 fuel line minimum.
If you feel you need a larger ehaust, I have one 4* bigger (331/300/219/.775"), you can check our specs at .200 against what you have, these are pretty fat.
They are all unsymmetrical, and give a long power stroke for their duration, putting more torque in the crank.

UDHarold

[bigjoe1]

I really like what Harrold says, but I dont use his cams. Your MPH is on the low side. I have a few customers with big 1967 Chevelles, and their MPH is much higher. 900 HP was at about 141-142, 1100 HP is 148-150 with a powerglide. 1100 with a Jerico is 152. These are about 3500 lb cars, but SMALL slicks (10.5 BY 29.50)I would try to reduce the weight ,BUT only in front off the drivers seat.
JOE SHERMAN RACING ENGINES