I had a customer drop off pickle fork jet boat, wants a low boost roots supercharger as much for looks as performance. He has a 1970 ls5 bbc, pulling motor and tearing down to see whats in it. Appears to be a 1970 ls5, from what I understand it would be 10.25 compression, closed chamber 100 cc head flat top motor. Oval port heads, 360 or 390 hp stock. Either ditch heads for 118cc eq open chambers, install dished blower pistons or freshen and run low boost, havent decided yet. Any input? Of coarse will be running and tuning on dyno

I'd go for the EQ heads, should drop compression back down to the 9:1 range, healthy flat tappet, and the blower. That should make him a happy guy

Just take the rotors out of the blower and run it. That's about as low as you can go for boost.

Im thinking more forged dished blower pistons since most likely has cast flat tops anyways unless i get it apart and somones put forged flat tops in then it will be eq open chamber heads

you can,t know for sure what has been done to the engine through the years .at this point it is speculation.get it apart and go from their.what does he have in mind for a blower?

Pulling motor right now, will beon stand tore down by end of day, customer knows nothing about nothing other than he want polished supercharger, dual 4bbls, bug catcher etc. Going to be a 6-71 since only a 454, block codes says its a 1970 454 ls5 OR a 402, again will know today what it really is

years ago i put a 8.71 on a ls5 for a guy,i told him the cast pistons were not going to last long,his responce was then we can build a real engine.within seconds of the engine going in boost it broke the skirts off all 8 pistons.i then proceded to spend a bunch of his money!

I wont in good conscience boost a cast piston motor, especially one i wont be driving, as of right now still dont know what it even id, has 1971 820 oval ports, i see stock pushrods and a melted black stock rocker armand fulcrum ball

Egads that woulda sucked. Sometimes engines parts just aren't happy but with good reason. I've seen some get lucky also but long jevity and any amount of boost "kaboom". If articfriends freshens the existing closed chamber heads with new good valves to sustain the heat I wonder what good dish piston would be to install and get his compression to high 8's. Who knows what he may all find after tear down. Gonna have to get balanced also.

Are forged pistons, 6-71, AND some EQ heads an option? Sounds like an easy way to 750-800hp ...