Did you check the oil for metal? It sounds like you could of wiped out a cam lobe or mushroomed a lifter. I'd pull the valve covers and see if all the rockers are opening the same.

If he lost a cam lobe you would here a lifter ticking. Increase the timing to 34* total advance. 16* initial will make it idle better.

as already stated,set total timing at 34.do not worry about initial timing.

Some Edelbrock 600cfm secondaries not working info:
http://www.gearheadtalk.com/forums/s...ies-won-t-open

Not always, a mushroomed lifter, or bent push rod will make noise but not a wiped lobe. He's checked almost everything else.

Not the secondaries.

Yes.....I'll continue to mention these until he checks them. LOL.

Yep - since he mentioned that it is a 600 cfm Holley, I am guessing it has vacuum secondaries. A vacuum leak at the diaphragm housing would not pull enough vacuum to overcome the spring and open the secondaries. And this is something that could possibly get progressively worse. Only way to check it is to put it under load and look down the secondaries. You could do that with the boat lashed to the trailer on the ramp, or run it and if a buddy is not around to watch it, mount a GoPro over the carb and view the video. That's what I did to check my fuel pressure by myself.

duplicate post

DJ..sounds like your motor mount might have loosened up and knocked the drive aleignment off..ck the lower nuts on the mounts..i have seen where they come loose and will bind up the coupler then the engine wont rev..

If the engine was that far out of alignment the coupler would stink of burning rubber. AND it wouldn't live long.