road race engine...
Think more rally car and less pavement.Without going into details or specifics lets just say I like to drive fast down rough roads many miles from BFN.
Sounds like someone is getting ready for the Rally of Idaho...???? We need to talk! I spent a lot of years and k-miles on-stage in a rally car. Won a couple of divisional championships back in the old SCCA Pro Rally days. Never did a Mopar though I've been thinking about it for fun!
Hoenestly, if I that is the case, I would de-empahsize the RPM's and 100% focus on making a broad RPM range engine. With RWD, you are going to need a very RPM-flexible engine and not a ton of HP; I can promise you that it is not the peak RPM's or Peak HP that counts in rallying;
it is the BREADTH of the torque band that counts. You can't put a lot of HP to the ground anyway. The old saying of not being able to put more than 100 HP per wheel to the ground in rally conditions will apply 90-95 % of the time.
And, even though you are starting with a good 5 speed trannie selection, you will not always have the optimum gear in all corners. Sometimes you will get caught 'between gears' and that is part of where the broad RPM range comes in. The other part is that you will always need excess drive wheel torque for the steering of the car that you will want to do with the rear wheel torque.... like a sprint car on dirt. The peak torque has to start at 2500 RPM or lower.
The cooling of the oil is important for sustained hard running like this. I always ran with an oil cooler and remote oil filter. Dry sump is not common in rallying; the cornering forces just are not great enough on gravel. You can do quite an adequate job with pan baffles. And all thinking of a deep sump go out the window; you'll bash it to smither-eens in the first stage mile. So that is part of the thinking behind the cooler and remote mount: a bit more oil capacity that way. Sythethics are a must IMHO; I found that the oxidation of the oil on a rally dropped hugely going from a good quality dino to a synthetic oil. And it can save your engine if you have a sudden leak. (There is a story behind that...)
All the comments of good lower end internals still apply, but with lower RPM's you can maybe sneak by with less. Hyper pistons now become OK and keeping the weight down. If I had to budget, I'd go with hyper pistons, SCAT I-beam rods, and a cast crank. Consider using a not-too-lightened or stock weight flywheel; a flywheel that is not super lightweight comes in handy for setting the car sideways into a corner with a downshift. The comment on on AL heads applies for sure... some Speedmasters would be fine IMHO as you don't need peak HP in this use.
You're biggest area of concentration ought to be the suspension. Are you planning on an A body? We need to talk suspension and brakes....
