500 HP is easy to come by NA w/ a small block Chevy. Very Easy W/ boost.
I would start with a stock 2 bolt main 350 block.
- Machine the mains in the block for splayed 4 bolts mains. (much stronger than the stock 4 bolt main block)
- Forged crank, (its a smallblock Chevy, so many choises)
- Forged rods, (same as above)
- Forged 8.0/1 pistons
- L31 Vortec heads, (LT1 heads cast in iron)
- yeah I would have to do some, ok alot of reasearch on cam selection, I really have no idea for turbo engines. _
But the above combo with say 9.5/1 pistons and the right cam could be capable of close to 450 HP NA
On a side note!!!
I was at PIR, Portland International Raceway, last night and there was a 67 Malibu,(Read big and heavy car), running a twin Turbo small block. It was a blow thru carb setup, not EFI, I feel EFI and boost were made for each other.
He had Master Power turbos, I have no Idea what size they were, but OMG did that car leave the line hard and pull like mad thru the intire 1/4 mile! WOW!!!!!! That car was running 10's in the 1/4 mile and he drove it to the track!!