7500 RPM 302 Stroker Suggestions

[Dumpling]

Most racing series attempt to LIMIT power and performance, attempt to keep everyone on an equal basis power-wise, making (theoretically) the driver's skill the determining factor in the outcome of the race.

I can't imagine any driver, Trans Am or otherwise, saying "I've got enough power in this car, it's enough".

Why don't you want as much performance as you can wring from whatever engine family you choose? Bore it, stroke it, cam it as big as you're willing to put up with. JMO.

[Mark O'Neal]

Originally Posted by Dumpling

Most racing series attempt to LIMIT power and performance, attempt to keep everyone on an equal basis power-wise, making (theoretically) the driver's skill the determining factor in the outcome of the race.

I can't imagine any driver, Trans Am or otherwise, saying "I've got enough power in this car, it's enough".

Why don't you want as much performance as you can wring from whatever engine family you choose? Bore it, stroke it, cam it as big as you're willing to put up with. JMO.

All you need is enough power, after that it's chassis and tires.

I can easily build a 3,000 horsepower motor for your Cobra, but you wouldn't be able you use it.

[xb-60]

Originally Posted by Dumpling

....I can't imagine any driver, Trans Am or otherwise, saying "I've got enough power in this car, it's enough"....

Haha.... that reminds me of that quote of Mark Donohue's ....

"If you can leave two black stripes from the exit of one corner to the braking zone of the next, you have enough horsepower."

Cheers!
Glen

[Mark O'Neal]

Originally Posted by Dumpling

Most racing series attempt to LIMIT power and performance, attempt to keep everyone on an equal basis power-wise, making (theoretically) the driver's skill the determining factor in the outcome of the race.

I can't imagine any driver, Trans Am or otherwise, saying "I've got enough power in this car, it's enough".

Why don't you want as much performance as you can wring from whatever engine family you choose? Bore it, stroke it, cam it as big as you're willing to put up with. JMO.

We built a pair of motors for Shelby when he was looking at running a sort of IROC series with Cobras. They went to Las Vegas for Mario Andretti and A.J. Foyt to do testing. They told them that we'd have to pull some power out if they wanted them to drive them.

My street Backdraft car made more power than those did.

Incidentally your third sentence conflicts with your second.

[MKS427]

Originally Posted by Mark O'Neal

All you need is enough power, after that it's chassis and tires.

I can easily build a 3,000 horsepower motor for your Cobra, but you wouldn't be able you use it.

A LOT of owners go cheap on the tires. That negates all the effort and money put into the powertrain and chassis. Spend for the Avons or R888Rs.

[Tremelune]

I've been trying to research building an engine like this. The biggest limiter seems to be valve float. 302-347 will all rev the same these days, though I don't know if the stock block is up to it. It seems easy to find heads that will rev to 6500, but hard to find heads that will rev higher. I see a forged crank and pistons recommended a lot. I've read there are hydraulic lifters that will work, but it may have been a fever dream since everyone recommended solid. Well-balanced internals; and light never hurts...Don't forget that you'll need a transmission that will handle it too (TKX).

The Ferrari 250 Spyder had something like 240hp at 7,000rpm with a 5,000rpm torque peak. The Jaguar E-Types had similar power with a torque peak slightly higher. Those are fun engines, and my car will see a lot more mountains and canyons than stoplights. Some like to feel G-forces from a dig, and some like to wind a smooth engine out for turn after turn, shift after shift.

[CowtownCobra]

If you are so into hi rev's, build a Cleveland

[Dominik]

Originally Posted by incoming

I'm sorry but i'm a realist.

It doesn't matter what we do to our cars trying to be purists.

We can't outrun a teenager with a chipped Mustang bought by mama?

We do look way cool though.

We can still outrun them, but I know exactly what you mean. Time caught up with us. That's why my last engine was a 390 FE with moderate cam.

[Alfa02]

There's a old saying "Nothing beats Cubic Inches" true today as it was back then. also, Torque is KING, as is you're in the torque range much more than the Horsepower range. we have in the hanger a West Coast Cobra, with a Cope Bros. built SVO 514 (609HP @5600RPM), that will "Chug" pass my high revving 347 (551HP @7200RPM) Pacific Roadster, all day long, again with the rear tires being the limiting factory, but I like it that way, much cheaper to replace tires than anything else in the drivetrain. My #.03 Cheers Tom.

[Streetwize]

The 363 is a nice combo for the 8.2 and even with a decent head like the Trick Flow 11R or the AFR 205 and a ported victor jr you should have ZERO problem hitting 7500 with small solid roller cam, Hydraulic cams can rev past 6500-7000 but a nice endurance type solid roller has a lot less mass and will be quite a bit snappier. But (if it were me and I was going to road race it at the track) I'd prefer the 3.25" stroke with the same 5.400 rod over the 3.4" stroke, which works out to almost 348 cubes, the lower piston speed and a better rod ratio is your friend at 7500 rpm all else being equal.

But for me the best combo would be a 9.2 Dart (Cleveland deck height) with a 4.125" bore and a ~3.70" stroke and with a long 6.125" or 6.2" rod using 2.0" (327 SBC size) rod journals with CHI heads and manifold. That would be more of a week-end 'run & gun" motor with at least a 3.90 gear and an overdrive....but you could still make plenty of power with a twisted wedge or AFR head.

396 cubes that would still rev to 7500 easy with a bobweight about as light as about the same rod ratio as a 331" 8.2 deck and assuming you go aftermarket block, really won't cost much more.

363 cubes will still move a 2500 pound car very quicky, the "trick" is to put plenty of head on it with strong mid lift flow but not so much port volume and cam to make the bottom end lazy. Compression is torque so even a 331 properly set-up will still get your attention at 2800-3000 rpm. My rule of thumb (assuming you build with adequate compression) is if you can get about 265 cfm at .450 lift you can make 500 hp pretty easy regardless (within reason) of cubes. So the smaller the cubes....the smaller the intake port CC will give you the best upper bottom and mid-range torque at a relatively small trade-off of "bragging rights' top end hp.