Join Date: Jan 2019
Location: Sedgwick, Kansas
Joe, I know you quadruple checked your timing, but did you verify that the marks on the damper (and the pointer) actually are pointing to TDC? Forgive me if I hit anything that's way beneath your level; I'm just going to go over the basics here, so you can hit the check boxes for yourself and figure out what's going wrong!
If the wires are on in the right order (and keep in mind, 5.0 engines and 351's use 13726548 instead of 15426378), then I suspect your mechanical timing's just not right. It is *possible* to get the valve timing wrong if you have an adjustable timing set, but if you are off by even one tooth on a regular cam, then it's not likely to ever start. So, most likely reason for backfires? Wrong ignition timing.
With that in mind, why not verify that the piston's where the damper and pointer actually say it is. You might think there's no way this could be wrong, but there are tons of dampers with different markings, and the same holds true of pointer position. Plus, the damper ring can sometimes slip. Pull the plug out of #1, and use a dowel in the hole to see where the piston's actually at. You could potentially use other things in the plug hole, but avoid sharp and pointy metal objects, or things that can bind/break/fall into the cylinder where they are hard to get out. Keep in mind - even when you've found TDC, there are two TDC's for the crank. One is TDC on the compression stroke, and one is TDC on exhaust.
Once you've proven to yourself that you're really at TDC, then you can set your base timing to something between 6 and 12 degrees, while you have your vacuum advance off the dizzy, and plugged.
At this point, it should run well enough to start tuning it up.
If not, the only other thing I can think of that might be doing this to you would be improper mix, probably caused by vacuum leaks. Under the carb is a pretty typical place, especially if you're running an Edelbrock manifold without some kind of spacer. There's not much of a wall for the gasket to sit against, and it doesn't match up very well with the underside of most carbs, so you will usually get a leak. If you're not familiar with running down vacuum leaks, I'd be glad to explain how to do that too.
Hope this helps!
"No matter what you are, be the best one you can." -Abraham Lincoln
Last edited by Grimbrand; 09-06-2019 at 02:29 AM.