You are currently viewing our forum as a guest, which gives you limited access to view most discussions and access our other features. By joining our community, at no cost, you will have access to post topics, communicate privately with other members (PM), respond to polls, upload content and access many other special features. Registration is free, fast and simple, join Corvetteforum.com today!
I'm into the "fine tuning" stage of my 454 build, and I'm looking for suggestions on the best initial and total timing set up. It's a .30 over with speed pro hypers(so I need to watch detonation) with a mild comp cam and 049 oval port heads.
Anyone have any good advise on a timing set up that has worked well for them?
My 427/390 was bored .030 over with a mild comp cam, forged pistons and standard-jetted Quadrajet. CR is supposedly no more than stock 10.25 to 1. I am running 12 initial / 32 total (not quite sure why only 20 centrifugal yet) on the timing with 600 miles on the engine. I know I can go more but with the Allen's 2-1/2" side exhaust I couldn't hear detonation if I tried. Occasionally dump a gallon or two of C12 in the tank and the engine really seems to like it...overcomes some of that supposed 10% corn crap. Hey, start lower and play with the total as your engine wears in. Sorta like cooking, you can always add something but difficult to take it out, especially if you hurt something.
Last edited by Faster Rat; 06-18-2010 at 08:15 PM.
Yep....I started at 8, but bumped it to 10 now. It still feels kinda "restricted" when I hit the gas. I've got to make up a timing tape to check my all in. I've only done a couple down the street and back runs just to get some pressure on it and seat the rings, so I haven't really punched it. It's a 4:11 rear with a close ratio muncie 21 so it's hard to keep the RPM's down too far, but nothing over 3K yet. I have side pipes and a gear drive, so I know what you mean about hearing the pinging. I figure with only 10 initial it shouldn't be a factor at this point. It's a 68 transistor ignition, but still has weights on the dizzy. I put the medium springs on it so the advance doesn't jump all in too quick at this point in the motors life, but I'm not sure if it would be better to get it all in sooner or not.
Last edited by whitehause; 06-18-2010 at 08:13 PM.
On a side note though, I've read that dial back lights don't work well on distributor ignitions, they were meant for use primarily on totally electronic ign systems. Any thoughts?
The person that wrote that is off in a weird place far far away. AS long as there's a reference (ignition pulse) to trigger the flash, and the "built-in to the timing light" electronics to adjust the timing of the pulse (flash) life is good.
There are several real good tech papers around to help you adjust your timing. You know what your compression is, what gas you have to run (based on your compression, cam, and aluminum or iron heads), so start there. Max is usually around 36* at 3000 RPM. Maybe back off a degree or two to make things easier on the hyper pistons, but that's your call.
I hate to sound like a dink. But give the motor what it wants, not what you think it needs. Thats what my engine builder always said to me. My 427 with 550 hp wanted 34 degrees total timing.ok my last 468 made 708 hp and wanted 38 total.
Start at 10 initial and then check total and see how the car responds. move up by 2 degree at a time. You will reach a point of detonation as well.The more initial the more it will blow the tires off on the bottom end, but you will run out of motor on the top end. Less initial will make it doggy off the bottom end.