I'm planning on building my own off road race car LS motor. A few specs will shed some light on my requirement. tire size is 40-42 inches, th400 is tranny used here, it also uses a 4wd transfer case distributing power to 4 wheels. So you see there is a considerable power loss thru this extreme drivetrain and tire size. Typically competitors have to run their xfer case in a lower range or their tranny in 2nd gear to have enuf power to maintain 70 to 100 mph on an off road course with woops and turns and road terrain variations to cause transient spikes in engine load. 90-100 is around tops for the straight front axle suspension. Calculations show 93mph occurs at 4000 rpm. My idea is: an l92 block with a 4 or 4.1" or more stroke, >12:1 compression running fuel, some kinda cnc'd head, a custom cam might make enuf mid range power to do 93mph at 4k and thus keep it in hi gears and lower rpms. All this under 10k in parts and machining. Any ideas or is this impossible?

 

Are you against using a supercharger or turbo?

 

Not technically, but the blower would probably bust the budget and it would be very tight to get the turbo's system in the engine area.