- Jan 19, 2009
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I have a 67 Mustang with a 428 from a 66 T Bird/C6. The engine has about 300 miles on it and I am having some detonation issues. Here are some specs on the motor. TRW 10.5-1 forged pistons, Comp cams roller rockers, Edelbrock perf. RPM intake and Edel 850 Carb, elec choke, FPP Tri-Y headers Jet Hot Coated, MSD6A box, MSD billet dist. I believe 8495 is #, it has black centr. advance stop and light silver springs as that is what the Dyno shop had in stock, (JUST GOT SPRING KIT WITH ALL SPRINGS AND STOP SIZES) The Cam is a Chet Herbert, .544 lift on int. and exhaust, 110 lobe centers. , 108 centerline, Int. duration 289, ex 303, intake open at 14 closes at 40, ex open 53 closes 9. C7ae-H GT heads pocket ported short turn radius worked and hardened seats otherwise stock. Went to dyno shop that had a Mustang Dyno and they said the air fuel mix was rt. but Engine detonates under load. Changed spark plugs to AR33's from Plat AP45's. Also running a 50/50 mix now with 91 oct. and 100Oct. gas. still pinging. Anybody running the MSD box and Billet dist. on a big block? What plugs, timing etc are you using to get rid of the detonation.
The current timing is 12 initial and full advance at 28 per the dyno shop, using the light silver springs. I have the heavy springs now and hope that will help the issue. Any suggestions would be appreciated. THX
The current timing is 12 initial and full advance at 28 per the dyno shop, using the light silver springs. I have the heavy springs now and hope that will help the issue. Any suggestions would be appreciated. THX