Anyone know the correct ignition timing for an OLDS 455? I'm running a Mallory single point distributor, 8* initial 30* total advance. Cam is straight up. Holley 850. She runs good but I'm wondering if I could get a little more power with more advance. From what I hear I don't want to run more than 34* total.
Thanks
that varies based on comp ratio, cam size, carb, intake,impeller, boat size etc, but I run 15 deg initial and 35 total on pump prem. I have L2323f030 pistons mild cam, torker, 780 holley pulling a AA impeller 18 ft boat and no probs for 4 years. bump key and she's running.
The boat is a 75 Spectra 20, mild cam from Mondelo, Torker intake, log exhaust, A impeller in a fresh Jaquzzi WJ, spinning about 4950 RPMs.
Thanks
try bumping up 2 deg and see how it does and maybe 2 more if it responds good. 34 is still pretty safe. listen for any pinging and double check plugs, worth a shot
Floored, Thanks for the info. Any thoughts about total advance? With a covered engine it's difficult to hear pinging. I'm almost thinking this 850 might be a little over carbed for this set up. Runs well, plugs look good but I've been told going to a 780 or 750 I'd see better fuel milage and better performance.
Thanks,
I'd just set it for 36 degrees, all in by 3000 rpm. Sounds like you're about right at 4950. That puts you at about 375 horse. I know you want that last 50 rpm though don't cha.Headers would probably get you close to 5200, but I know they dont fit mine. The motor sits too low for them to clear the rear deck. I guess there are other options, but not many for the olds.
sounds like its pulling the upper rpm's good with the 850. with my 780 its hard to just set it at 42-4400 for cruising because of the vacuum secondaries. I'm a little under carbed right now but it runs every time and I ain't messing with it. I'd just work on fine tuning what you have, it seems to be cranking along pretty well
Posting Permissions
Reply With Quote