331ci horsepower

[phantomfab]

All in the name of budgeting and just using what was in the shop. The combination is a 331 cubic inch small block chevy.
The Specs:
4.030 bore stock gm block
3.25 in stock crank
5.7 rods
4 cc flattop forged speed pro pistons
ct101 camshaft installed straight up
https://static.summitracing.com/global/ ... -ct101.pdf
461x heads with 1.94, 1.6 valves. Valves deshrouded and a 5 angle valve job.
strip dominator intake.
750 gaerte methanol carb.

Just curious of what kind of power this combination will build and what rpm range it should be operated in.
In a 2500 lbs car. Circle track. Looking for 4500-7000 rpm range.

Thanks for any input.

[swampbuggy]

I will break the ice and estimate 400-425 at 6500-7000 i like the combo, the heads will be your ball and chain though. Mark H.

[phantomfab]

I understand that the heads are the weak link in the combination. Having a cast crank and stock rods I did not want to use a good set of heads with fear of the bottom end not supporting the power or rpm needed with much more. Is methanol a good choice? And the cam is one we had from an engine that split a cylinder. Was expecting it to work well to somewhat band aid the head. What I am wondering is how driveable the combination would be or if it will be "peaky" so to speak. And a general idea of power was also something I was curious of.

[phantomfab]

It does have 1.6 rockers arms on it so cam numbers will change slightly.

[mag2555]

Keep a eye on your valve sealing with that 5 angle valve job after about 5 races!
Once you break the motor in do and record the results of a compression test to have a base line on the motor.

[Walter R. Malik]

All in the name of budgeting and just using what was in the shop. The combination is a 331 cubic inch small block chevy.
The Specs:
4.030 bore stock gm block
3.25 in stock crank
5.7 rods
4 cc flattop forged speed pro pistons
ct101 camshaft installed straight up
https://static.summitracing.com/global/ ... -ct101.pdf
461x heads with 1.94, 1.6 valves. Valves deshrouded and a 5 angle valve job.
strip dominator intake.
750 gaerte methanol carb.

Just curious of what kind of power this combination will build and what rpm range it should be operated in.
In a 2500 lbs car. Circle track. Looking for 4500-7000 rpm range.

Thanks for any input.

Are the heads allowed to be ported...?

[Tom Walker]

Are the rods factory production, or aftermarket? Seems like sustained circle track racing with a somewhat heavy piston is asking a lot from the rods if they are stock rods at 7000 R.P.M.

[groberts101]

Are the rods factory production, or aftermarket? Seems like sustained circle track racing with a somewhat heavy piston is asking a lot from the rods if they are stock rods at 7000 R.P.M.

You may be on right track about the piston weights but the shorter stroke will help rod durability a bunch.

That cam seems a tad too big for those heads and the shorter stroke. I'd guess it'll feel softer until about 4,000 rpm. Could put more gear in it but that'll just make it peakier feeling and tougher to drive.

My guess is right around 400 or maybe just a tad more with meth.

[phantomfab]

Yes they are stock rods but they have good rods bolts at least. And I think they will be okay because of the shorter stroke at 7000. I actually plan on chipping it at 7400. And under 4000 isn't too much of a problem because racing it will seldom see that low of engine speed. The heads can be ported while they are in the car they are currently in. I left them unported in case I want to change the intake and run it in a factory stock that does not allow them to be ported.

[Walter R. Malik]

All in the name of budgeting and just using what was in the shop. The combination is a 331 cubic inch small block chevy.
The Specs:
4.030 bore stock gm block
3.25 in stock crank
5.7 rods
4 cc flattop forged speed pro pistons
ct101 camshaft installed straight up
https://static.summitracing.com/global/ ... -ct101.pdf
461x heads with 1.94, 1.6 valves. Valves deshrouded and a 5 angle valve job.
strip dominator intake.
750 gaerte methanol carb.

Just curious of what kind of power this combination will build and what rpm range it should be operated in.
In a 2500 lbs car. Circle track. Looking for 4500-7000 rpm range.

Thanks for any input.

Are the heads allowed to be ported...?

Those heads are almost 260 cfm at .600" valve lift when ported with that valve size.

420 HP when un-ported, ( the cam is to big for that and will simply lose torque without much gain in horsepower ), and 485 when ported decent.

[phantomfab]

Keep a eye on your valve sealing with that 5 angle valve job after about 5 races!
Once you break the motor in do and record the results of a compression test to have a base line on the motor.

Thanks for the tip. I have never had an issue in the past but I guess it is a good practice to check it every so often for the comfort of knowing. This engine will only run maybe 6 nights this season though. It is in the backup car that we use at shorter tracks that race a little close for comfort in the primary cars that run for points.

[phantomfab]

7400 was the rpm of choice because that puts piston speed right at 4008 fpm. Which I figured would be a safe area to stay with stock rods.

[jed]

If the engine is making 400/450 HP the stock rods should be changed between 1800 & 2000 laps.

[phantomfab]

If the engine is making 400/450 HP the stock rods should be changed between 1800 & 2000 laps.

It will be pulled apart with no more than 500 laps.

[tresi]

You are leaving too much on the table. A little here, a little there, a little everywhere adds up to a bunch. Build it and sell it to a bracket racer or street rodder and get what you need.