Posted By: Hangtowner
full ign advance less than 30 - 11/26/21 10:55 PM
fresh 440, 10:25 compression with Ebrock performer aluminium heads. Lunati 268/274 cam. 4200 pounds and 3:08 gears.
With the standard Mopar distributor with big and little springs, it pinged at full throttle at 4000 rpm which is 30 degrees(about 5 degrees initial). I put the FBO plate in it, changed springs for full advance at 3400 rpm. With the plate set for 16 degrees crankshaft and 15 initial, now it pings at 3000 rpm. I can now keep backing off to find out where it doesn't ping and that will probably be well below 30. Did we just build this engine with too much compression even for aluminum heads? What is so magical about the usual 34 degrees?
With the standard Mopar distributor with big and little springs, it pinged at full throttle at 4000 rpm which is 30 degrees(about 5 degrees initial). I put the FBO plate in it, changed springs for full advance at 3400 rpm. With the plate set for 16 degrees crankshaft and 15 initial, now it pings at 3000 rpm. I can now keep backing off to find out where it doesn't ping and that will probably be well below 30. Did we just build this engine with too much compression even for aluminum heads? What is so magical about the usual 34 degrees?