Reinstalling factory type distributor (from a 1972 Cutlass) with Pertronix conversion in my 1965 442 with 400ci.

What is a good suggested initial base timing to start with (with vacuum line off of course)?

Thanks in advance!

 

The stock setting for a 65 400 is 7.5* @ 850 RPM where as a 72 distributor it's 8* @ 1100 RPM both set with vac advance disconnected. The 2 curves are a bit different and what I would do is set the timing to 34* at the RPM that the distributor stops advancing and let the initial be whatever it winds up after that. Then make a note for future reference what that initial timing is when done. You may have to limit the vac advance to 10* if it is bringing too much advance at light cruise.

 

Then give it as much timing as it will tolerate without spark knock, which will eventually lead to tuning the vacuum and centrifugal.
I like the vac advance hooked to a full-time vacuum signal, not a ported port.

 

Best advice.

An easy way to do that without the high revs is to disconnect the advance springs, start the car, give it single low-rev bump to set the weights, and adjust the advance to 34°.