Expert: Robert Summers - 6/19/2009

Question
I have a 69 camaro with a 427 bored 60 over, a 550 lift hyd cam, 850 holley. first to clarify does BTDC mean Before or Below. i have number 1 at top dead center, both valves closed and the rotor pointing to #1 on the cap, it runs smooth at 9oo rpm at 12 deg btdc there is no way i can get it to 35deg atdc at 2000 rpm, where am i screwing up, please.

Answer
Hi Al...BTDC means before top dead centre...i take it that you want 35 degrees of advance...you give me the cam lift but what is the duration. did you dial  in the cam when you installed it. does your distributor have enought turn in it for 35 degrees. usually those engines should be at between 6 and 8 degrees BTDC to start.. with vacum to the dist off and plugged. as that cam is a little lumpy it should run a bit rough at 700 to 800 rpm. make sure you are connected to ported vacum at the carb.then try to see if you can bring it up to 35 degrees you may need to change the dist to get that much advance...hope this helps