I can't get rid of detonation! ..... I have put about 1000 miles on rebuilt engine now. Seems to be using a bit less oil since the oil change at 500mi. Ran several tanks of 93 octane but pings throughout entire rpm range wot. I power timed it of course. All 30 degrees in at 3000 rpm. I talked to Tim at taperformance and he and their engine builder think the silvolite pistons are creating too much compression for my iron heads. But it doesn't matter if my engine is hot or just getting warm. It pings throughout range with wide open throttle. Mallory unilite conversion setup...... I have to retard the timing about 10 degrees to get rid of all detonation. I'm discouraged.
So, how much in the hole did those pistons end up? Are you sure that the the distributor isn't advancing beyond 30* after 3000 RPM?
You use vacuum advance? Did you supply pistons to shop that bored it? They mic them and bore accordingly for proper skirt clearance with your specific piston material. File fit rings?
OK, so Silvolite 1734 Pistons. https://www.summitracing.com/parts/uem-1734-030 1.808" compression height. 10.187" Stock 350 deck height 3.85 Stroke 6.387 stock rod length Stock deck height minus (1/2 stroke + rod length + compression height) = pistons in the hole. 10.187 - (3.85/2 + 6.387 + 1.808) 10.187 - 10.12 = .067" in the hole. So TA 284-88H cam, 284/288/110 LSA. Supposed to be installed 4* advanced, 106* ICL (we don't know for sure, not degreed) Static compression, Dynamic Compression, Might be too much.
I mentioned posts ago. Stand on it, seat the rings, it won't run any better than now when it's basically carbon free. Oil usage shouldn't be, with only 300 easy miles if rings are seated.
Actually, your first step is to verify your maximum ignition advance WITHOUT the vacuum advance. To do this properly, you need the lightest springs so you are sure when the mechanical advance is ALL in. Then set that maximum advance to 32*. Once you have done that, then use heavier/different springs and play with the rate of mechanical advance. The goal is to eliminate any detonation at WOT. Once you have done that, THEN you add the vacuum advance and tune that to eliminate part throttle ping.
Cams have been known to have been ground off spec. Lining up the dots tells you nothing in some instances.
