Oval track cam/head/stroke questions

[Krooser]

Most of you guys have already figured out I'm not the sharpest pencil in the box. But I do like to learn.

So I have my 360-based 383 SBM with W-2 heads. Dirt track application. I had a cam recommendation based on my heads flowing 280-ish and my max. rpm's of 7,000. The cam I'll be running is 591/567 lift, 254/260 duration @.050 on 108. 750 cfm on alky. 13.5-1. 3.79 stroke.

This engine formerly had a Crower of about the same specs (545/558 lift...250/254@.050 on 108) then a Mopar Purple Shaft. Never ran over 6500 with the PO driving.

My buddy runs a SBC. Spec Brodix heads that, IIRC, flow about the same on the intake. 215 cc intake. He runs his motor at 8,000 rpms. Not sure of the cam specs. About 650HP he sez. Comparable to bunch of guys in the same class. 750 cfm on alky.355 ci.

Questions... does that Chevy need to spin that fast? Wouldn't the heads be a limiting factor and maybe even a restriction at those rpm's?

Just wondering. I'll be helping him (I think I'll be of help) this season. Just trying to understand this engine.

Thanks.

Rick

[Krooser]

Xxxxxxx

[barnym17]

A lot of guys gear to run on the back side of the torque curve past the midpoint of the straight easier to keep hooked up. Plus you have more power at corner exit when you need it most.They run way past their hp peak rpm for driveability.

[Walter R. Malik]

Most of you guys have already figured out I'm not the sharpest pencil in the box. But I do like to learn.

So I have my 360-based 383 SBM with W-2 heads. Dirt track application. I had a cam recommendation based on my heads flowing 280-ish and my max. rpm's of 7,000. The cam I'll be running is 591/567 lift, 254/260 duration @.050 on 108. 750 cfm on alky. 13.5-1. 3.79 stroke.

This engine formerly had a Crower of about the same specs (545/558 lift...250/254@.050 on 108) then a Mopar Purple Shaft. Never ran over 6500 with the PO driving.

My buddy runs a SBC. Spec Brodix heads that, IIRC, flow about the same on the intake. 215 cc intake. He runs his motor at 8,000 rpms. Not sure of the cam specs. About 650HP he sez. Comparable to bunch of guys in the same class. 750 cfm on alky.355 ci.

Questions... does that Chevy need to spin that fast? Wouldn't the heads be a limiting factor and maybe even a restriction at those rpm's?

Just wondering. I'll be helping him (I think I'll be of help) this season. Just trying to understand this engine.

Thanks.

Rick

Getting an engine to run in it's best horsepower range is what they are doing.

Horsepower is torque at RPM so, as long as the torque is not dropping a lot faster than the RPM is rising they are better-off.
They put more gear in it and use it.

Finding that most advantageous range is where it needs to be.

[fast_crew]

With Max RPMs of 7,000 I'd look at something with just alittle less duration. Say 250/254, 252/256 just my opinion though.

[Krooser]

Most of you guys have already figured out I'm not the sharpest pencil in the box. But I do like to learn.

So I have my 360-based 383 SBM with W-2 heads. Dirt track application. I had a cam recommendation based on my heads flowing 280-ish and my max. rpm's of 7,000. The cam I'll be running is 591/567 lift, 254/260 duration @.050 on 108. 750 cfm on alky. 13.5-1. 3.79 stroke.

This engine formerly had a Crower of about the same specs (545/558 lift...250/254@.050 on 108) then a Mopar Purple Shaft. Never ran over 6500 with the PO driving.

My buddy runs a SBC. Spec Brodix heads that, IIRC, flow about the same on the intake. 215 cc intake. He runs his motor at 8,000 rpms. Not sure of the cam specs. About 650HP he sez. Comparable to bunch of guys in the same class. 750 cfm on alky.355 ci.

Questions... does that Chevy need to spin that fast? Wouldn't the heads be a limiting factor and maybe even a restriction at those rpm's?

Just wondering. I'll be helping him (I think I'll be of help) this season. Just trying to understand this engine.

Thanks.

Rick

Getting an engine to run in it's best horsepower range is what they are doing.

Horsepower is torque at RPM so, as long as the torque is not dropping a lot faster than the RPM is rising they are better-off.
They put more gear in it and use it.

Finding that most advantageous range is where it needs to be.

The guys running 800hp RY45's are running the same rpms as the guys with the spec heads and 150 less hp. Of course the big 410's are a lot quicker than that 362 spec motor.

I guess I could never afford to run those big revs...

[RCJ]

When I was racing the SPEC heads we turned around 7200 with legal heads ,8200 with ported heads