Quote: I'll guess I'll find out soon, I'm also running J12's. Don't know if it matters but the 2 1/4 pipes are like drinking a thick shake thru a soda straw. I'd unhook the vacuum advance, bump the jets up 2 and back the timing to 35* at 2400 and see if that helps.
But you have good quench , he doesn't. You might want to find a set of equivalent heat range to JY10's ?
John I'm dumb on quench.. I've never worried about it much. I've used 906 heads, 915's, 516's, and the rest on 383's and 440's and never had issues. Most were 9:1ish stock bottom end motors, except for the 11:1 383/915/509 cam motor. Whats makes mine a non-quench problem? the 516's? I mean my slugs are only .020 down (or there abouts)
Yes the 516's , closed chamber , what head gasket did you use ???
I know of guys with 9.0ish compression that just did poorly thought out builds have detonation issues with lower octane fuel and too much timing . I built a good quench distance 440 for a friend with 10.3 compression and 906's that doesn't have any detonation issues with 93 octane and 38* total timing .
