I'm looking into stroking my 502 to 540ci with forged internals, Lower the CR to approx 7.5-8 :1 and add a 871 Blower on top !!!!
Im looking for 750 to 800 HP motor
Im using my dart iron eagle heads and cam is a 525efi cam
I cruise alot at 3500 RPM and when I go full throttle its only for a couple minutes
Here are my questions ....
Can I run on 89 octane with 5 to 6 psi of boost ????
If yes what CR would I need to run 89 octane ???
Twin 750 carbs or 850s ????
Is 800 Hp possible ?????
I dont plan on spinning the motor past 5400 RPM !!!!!!!!!

i'm no expert but what i've seen in builds in person, I know that what you are looking for on that build/ compression a 540 around 5-6psi you do need to run 93. also would have to go bigger fuel to get closer to 800 im thinking. and if you aren't running past 5400 I doubt you'll see that number id say closer to 700-720hp at 5400rpm if you were to spin 6000 I would say you'd be closer to 750-800.

Have a 509 with 8-71, two Demon 850's, Underdriven to 6+ or 7 lbs of boost. Would have to look at dyno sheet, but was about 830 HP. Only ran 94+ fuel

Looking for 750-800HP? No problem.

Icdedppl's 540's made really close to 900hp, on two different dynos. Dart iron eagles, 10-71 blower, 8lbs boost on dyno. Crane 139651 camshaft. At 5500rpm, it was making about 840ish. Nothing exotic, iron heads, shelf pistons, shelf cam, shelf carbs, etc.

750-800 is very doable with your combo, even with the smaller cam and 871. Actually, you can do it with the 509 combo.

Go with the 850 carbs.

Thanks Guys I appritiate the info
Here in Malta at the Marina we only have 89 octane unfortunately
I think ill be better of and more reliable with a 9:1 CR big cube N/A motor to run 89 safely like a 598 or 632 and make impressive torque without spinning the motor past 5400 rpm
Not sure what road to take .....

Plus since I raised my Engine 3 inches to raise the X, I dont have any room left in my 29 scarab !!!!! I checked yesterday and the Air cleaner is a half inch below the hatch so the blower with carbs on top will be extremly high so I cant go much higher and I hate scoops