Originally Posted by Caballerokid
Thanks to Cobalt327 for posting some helpful timing information in another post, here is where I am right now.
I adjusted the accel pump cams and the adjuster bolt. Added a 10° vacuum advance curve starting at 10" of vacuum and all in by 4" of vacuum and I hooked it to ported vacuum as I am already running 19° initial advance. I changed the mechanical timing curve to 15° all in by 3,000 rpm. Drove it and it drove well and responded well but had a lean spot off when cruising just off idle and cleaned up with more throttle. I went home and (until I get another set of discharge nozzles) put my .036" squirter on the primary and the lean spot was GONE! Ya, its a little rich now but I need to go down to about a .032" squirter and all should be great until I get better gearing and will have to do this all over again
So here is the e-curve timing; 19° initial, 15° mechanical (by 3,000), 10° vacuum advance 10" in by 4". Math says a total of 44° but it's really about 45-46°. Also Spinn I'm not using the rubber o-ring seals on the inside, just the top gasket. I haven't had any problems at all with it. Just understanding it more as it works backwards from a conventional HEI dizzy.
sticking to it until you got it sorted out.
I really am a fan of the 4777 Holley- I believe it's one of the most flexible carbs out there and it can work well in a wide variety of situations. I have had one on engines as far apart as a 0.030" over Pontiac 455 (ran mid 12's) to a '68 Pontiac Sprint OHC 250 ci 6 cylinder inline engine (originally had a Q-jet from the factory). I used the 4777 while I did my first