I recently performed an HEI points conversion on my 1966 Electra, only with the help of you kind folks! I got to the point where all is hooked up properly, but left to go south for vacation, so didnt have the chance to fully finish. I cranked it once and fired, yet ran very rough, which I contributed to the vacuum advance needing adjusted. When I returned, I started the process and before I go too far, wanted to see if i should be concerned. I put a little fuel to start up because it sat for a while, and cranked with it firing. It still ran rough, but also spit some fuel back out of the carb, so I shut it off and came here just in case it was something more severe........ Is it due to the vacuum advance being too far retarded, the opposite, or something crazy? It ran wih no issues before the HEI fyi. Can anyone give me an idea if this is normal? Thanks!
Given the simplest answer is usually the right one.. whats the last thing you touched? I'm willing to bet its a base timing issue, and as Larry suggests I'd check timing first. It likely has noting to do with the carb.
Checking timing is something you do once the engine is running. The problem is static timing when installing a new distributor. That is more difficult with the big cap HEI. BTW, the OP did not have a timing light the last I heard.
I guess it depends on what you're used to. I'd have said the HEI is the easiest distributor on Earth to set static timing on. The only tools needed are a screwdriver or nut-driver to remove the cap and rotor, and a distributor wrench to loosen/tighten the distributor hold-down bolt. Put the crankshaft at "your choice" of degrees before (advanced from) TDC #1 (or #6, the only difference is where the rotor points.) Perhaps you want your initial timing to be 14 degrees advanced--put the crank at 14 degrees advanced, turning the crank in the normal direction of rotation. That keeps the slack in the timing chain from interfering with the results. Visually line up the pickup coil teeth with the reluctor teeth by turning the distributor housing. You'd feel the magnetic pull as you do so. When they're lined-up, tighten the distributor hold-down. With some practice, you should end up within a degree or two where you intend the timing to be.
I'm talking about the mechanical interference between the big cap and the front of the intake manifold, and sometimes the upper radiator hose. If you don't get the distributor in on the right tooth, the cap can hit when you go to turn the distributor while adjusting your preferred initial timing. Not saying this is always a problem, but it can be.
Yes, but my remarks were general, not specifically concerning the OP's engine. I should have stated I was talking about the later Buick V8s. How close does the Big cap HEI come to the firewall in a Nailhead application? Any interference with the air cleaner?