Another timing question

I am helping a guy with an olds aluminum block with Big Chief heads. Compression is 11.5, 14:71 hi helix blower. Not sure what to run for ignition timing, he has an MSD 20. Any thoughts?

 

My experience with a Big Chiefs is with a high helix, std helix and even an early psi they don't want much more than 32 degrees (definitely don't like more than 35) with a mallory mag. std BBC heads I've run usually need a bunch more than that like up to 40 with big domes. Mallorys retard about 4 degrees under load so I'd say 28 degrees with big chiefs and a MSD mag.

Marty

 

Ken, we run a 526 kb olds in my altered and the motor seems happy with 30 degrees. Hope this helps and good luck

 

Thanks guys.

 

ken 30* is good but is it a automatic are clutch car an automatic car you may have to knock more out at the hit then ramp it back in if it has trouble leaving are shaking the tires down low

 

It's a powerglide car, I am crossing my fingers that it is going to live.

 

timing

what do you guys think about timing in a 540, 12.3:1 compression, conventional BBC heads, 8-71 Kobelco 20-30% over, for timing?
thanks

 

We had a 509 with 8/71 on it ran 34 degrees timing and seemed to be happy

 

We had New Century block with Big Chief heads a 14-71, Lencodrive and a Mag20. At 34 deg's we bent 1/2" push rods and pulled rocker stands out of the heads from detonation. later we found a couple of wrist pins bent as well. At 28-29 deg's she was happy and running 3.90's 1/8 mile times.

Paul,

 

In our boat we are running a BBC/Rodeck with a 14-71 HH Littlefield and a Big Chief Heads with a Mallory 4 mag and have been running 30 degrees and have had good results.