hi guys. i got the carb tuning and ignition timing right this weekend. the engine is a 350 ho deluxe unit with a holley 4160. according to the manual; the total advance is 32 degrees wot. i use the recommended fuel of 92 octanes btw. first i set it to 32 and gave it a little more, did some road testing ended up with 34 degrees with no pinging, detonation etc. the car just runs very strong and healthy right form the idle; except beyond 4000 rpms; the power just stumbles and it feels like its revving freely without making any additional power from 4000 to 5000 rpms where it should produce top power. i didn't have the chance to play with timing even more; maybe it could take in another couple of degrees but would it cure the problem? or is it my poor old not rebuit th350 tranny that came with the orginal six cylinder keeping me form going byond 4000 rpms?

the vacuum reading is 17 hg at 900 rpm idle speed btw.

I'd throw a little jet at the secondary side to see if it picks the acceleration up a little bit, keep the timing at the 32 to 34 degrees.

Does it happen in each gear? Any major mods to the engine...like a big cam?

What RPM does the full advance come in? You want it to come in around 3,000-3,500.

no mods to the engine. it happens in each gear bu feels especially bad at first. the timing is set at btdc 32 degrees at 4000 rpm.

Could be a number of things-weak valve springs, not enough fuel pressure and/or volume. How old and what kind of fuel filter do you have? Maybe your engine likes more ignition timing. Try advancing it a little at a time and see if it helps.

the engine is brand new and runs healthy, don't think there is a problem with the valves but it could be fuel delivery related. the filter is new as well but i'll check the fuel pressure.