What Am I Doing Wrong With setting my Timing on my 455 olds engine?

With the vac unhooked from the dist... I'v tryed setting the timing at 10 BTD and At 12 BTD... If I go any lower on timing it will not run... But at 10 BTD or at 12 BTD it will run ok at idle...But it spark knock it;s *** off at top end "only under a load" ....This engine that I have is a 1970 w30 455 with 11.0.1 comp... I'm runing a stock 1970 w30 cam duration is 232 at .050... And I'm runing a set of 1968 stock 400 heads (c) casting with big valves they have bin ported a little.. With a edelbrock performer intake and a stock q jet carb..""""""This engine is all most stock """" Can any one out there tell me what I'm doing wrong???""""""""""""

What Am I Doing Wrong With setting my Timing on my 455 olds engine?
Hmm, 11.0 compression. I am assuming you are trying to set the timing using premium gas that is less than one month old? Try about 6 to 8 degrees - I know it sounds crazy, but I bet it works and isn't that what matters? With the heads and pistons and what you have said without going into an explanation that looks like it came out of an encyclopedia, I think 6 is going to be pretty close.
Reply:Forget the timing light! Time it by ear. With the engine running and the distributor just loose enough to turn, hold the throttle around 3000rpm and turn the distributor back and forth until the engine sounds the best with the most throttle response. Tighten the distributor and go blow the doors off a Ford!


This is the way I always time engines.
Reply:sounds to me like your off start over and redo what you started with .. best bet your off a tooth
Reply:What is the octane of the fuel you're using? Are you using any octane boosters? At 11.0:1 compression 87 octane fuel will spark knock like crazy under any kind of a load - 91 octane fuel that they call premium now is what used to be regular - and premium then was 95 octane.





If the timings on, and it sounds like it is, then you may want to put some octane booster in the tank and see what happens.


I know it doesn't seem correct, but the higher the octane, the slower the burning fuel...
Reply:what about setting it in between 10 and 12, also another thing alot of people get wrong, is where do you have your vacuum advance hose hooked up to?. if its hooked up to the intake, take it off there and hook it up to the ported side of the carb. hooking it up straight off the intake, its advanced all the way and when you want more power, it cant advance anymore, because its advanced as far as it can go.what i mean by ported is find a fitting on the carb above the throttle plate, that only sucks air when you give it gas, that way when you give it gas, it can advance and hotten the spark more, to give you the power you need.