whats up guys,
my engine is spark knocking every time the trans goes into second gear.
it also happens when i accelerate hard. the timing is dead on.

i have a small holley carb with vacum secondary, i also have the biggest cam possible,without having to have a stall converter.
could the vacum be too low coming from my carb going to the distributor and the power brakes?
if so what can i do to correct the problem?

its killing my horse power!

 

Can you post some more information about your engine and cam? Also, what is your base timing set at? How much total advance are you running?

Usually pinging is caused by excessive ignition advance, too hot of a spark plug heat range, carbon deposits, or a lean condition.

If you have a large cam with a street-oriented carb, it could be running lean. How do the plugs look? What color are they?