Senior Tech Team
Join Date: Apr 2012
Location: Yerington, Nevada
Re: New heads and intake, now engine bog off the line
"initial timing is 12deg with another 24deg from mechanical advance for a total of 36deg".
"HEI ignition from performance distributors." Run of the mill ignition, at best.
For a 400, initial is just fine, they have a long stroke, and 12 for one of them is like 16 for a shorter stroke 350.
What IS needed, is 10 more degrees for the vacuum advance, set with a positive stop on the V/A pull pin, and connected to full manifold vacuum sourcing, bottom of the front of the carb (Carter junk will e on the DRIVER side of the carb, NOT THE PASS SIDE.
12 INITIAL + 10 VACUUM ADVANCE, ON FULL MANIFOLD VACUUM, will give you the 22 deg/BTDC @ IDLE, the engine will enjoy it, and will still start easily. It will also allow the throttle plates and idle speed to be lowered to a reasonable level.