Ignition timing

[bumble]

Hi everyone,

I just replaced my stock distributor with an MSD unit and have a couple of questions about timing. My motor is a 1970 455 with a Kenne Bell Maxi 3 cam, untouched non-stage heads, headers from TA Performance and Kenne Bell hypereutectic pistons. Compression is unknown but I believe it's somewhere between 9 and 10. Cranking compression is about 170-175 psi. From all I've read on this board and others my pistons absolutely hate detonation, so I've tried to stay far away from it. In setting up the timing I picked a curve (using the springs supplied by MSD) that is all in by about 3500 rpm. There is an advance stop bushing on the distributor that allows 21 degrees of mechanical advance. Add that to my 12 degrees initial and I'm at 33 degrees total. My main question is, is too much advance or too little advance a cause of detonation? If so, which one? I understand from many of the articles I've read that our 455's like about 34 degrees of total advance, depending on mods. So from a performance aspect I should be ok. But what about from a detonation perspective? The vacuum advance has not been hooked up yet.

My car is only street driven, just something to enjoy now that the weather is warming, so I'm not looking for that last 0.1 second at the strip. I want it to run safely and reliably on the 93 octane I buy. I guess I should also mention that it's a 1972 Skylark convertible, Turbo 400 with a 3.42 (I think) posi.

Thanks for the help!

Mark

[70 gsconvt]

I've always read that you want to get that timing in early, like at around 2200-2300 rpm's. I would think a lighter set of springs would help out.

[69GS400s]

Here's a link to just about everything you (n)ever wanted to know about timing a 455 written by BPG Member Larry, who frequents this board ... so feel free to ask questions either at the linked site or here

http://v8buick.com/showthread.php?t=...t=power+timing

[bumble]

Ahhh, perfect. Thank you, gentlemen!! I believe Larry has helped me a number of times over the years on various boards. Thanks for the link and the advice!

Mark