I have a 355ci. chev. with a 268 extreme Comp cam, vortec heads, 750 Holley, Headers all the basic stuff. I'am trying to get the timing right and i'am not sure what it should be, base line as well as total advance timing. I know this can very from motor to motor but I would appreciate some imput. I tried it at about 38 total and I have quite a bit of spark knock. If someone could get back with me it would help alot!!! Thanks NORT

 

Total timing of 34 degrees will probably work. It also depends what rpm your total is coming in at. If the curve is too quick it could cause pinging. If you are using vacuum advance it could cause a problem at part throttle if you have too much vacuum advance, but wouldn't affect full throttle operation. If you are at high altitude you would need to retard timing a little more.

 

start with about 10 to 12 degrees initial. Don't let it start advancing b4 about 1200 and try to get it all in by about 3200 rpm. most factory dists are limited to about 18degrees internally.