Knocking under accelleration on rebuild

[omega1940]

Just finished a complete engine rebuild. Some of you may remember the problems I had. Only one problem left. Here's what I did in the rebuild (major components) on my 88 L-98

Bored .030 thousands to 383 stroker
Accell SuperRam intake
Accell Long-Tube Runners
Ported & polished plenum
Bosch 24 lb. injectors
Crane "Gold Race" roller rockers
MSD 6AL
Peformance Products HEI Coil.
Scat 383 Crankshaft, alum. pistons, clevite bearings, etc., etc.
Double Roller timing chain.
Ported & Polished heads
Hooker Headers
Billett Flyweel
Used L98 block, 4 bolt main
CenterForce 11 Dual Friction Clutch

Already had a 52 mm. throttle body, Flomasters, K&N, adj. fuel pressure, etc.

Got the rebuild done about 2 weeks ago, and am now through the break-in period. I had Jeff make a new chip before this rebuild. When I was finally able to romp on it a bit this week, I discovered some loud "dieseling" or knocking at about 3500 rpm. I called my builder and he said the timing was set at -6 degrees without the emc ?? connected, and that the timing advance was controlled by the PROM. I sent away to Mid-America where "Formato's Fasterproms. Inc. (www.fasterproms.com) is advertising a custom chip for Stage I, II and III. The first chip they sent me didn't work because Mid-America had not told them I had a stage III mod. engine. They sent me a new chip a couple of days ago and it would not work. It shut down the engine at 3000 rpm's, much like I would assume a rev. limiter would. My MSD AL6 has a rev. limiter set at 6000 at the moment.

I am thrilled at the performance of the rebuild, but I can't really say how it will do in a quarter, etc. because of the top end knocking or dieseling. Formato's is sending me a couple more chips with different specs to try out, but it seems like a hit or miss thing to me.

Any ideas?

Thanks,

Mike

[miken]

I have an Ed Wright chip and no problems after rebuild.