I recently bought a 68 442 vert. was told it was 455 that was a lie found it to be a 400 with c heads. Someone before me replaced the distributor with a mallory unilite the vacuum advance can is plugged off. It has a holley 750 on it presently it also is a 4 speed. My problem is it has a stumble when you are just driving normal between gears. I have been through all of the carb stuff changed from 30cc pump to 50 with a 42 squirter it has gotten better but i really think it all has to with no vacuum. If you hook vacuum up to manifold oh heck no all it does is back fire pop runs like crap. Hook vacuum up to ported stumble is still there. Timing is set 10 initial 34 total any advice driving me nuts. If you really get on it between gears she runs like a raped ape but I hate driving it like that all the time. Let me also state I have alot vacuum at manifold close to 30 hg at idle is that right sounds like alot if you ask me. About 8hg at ported. Any one got anything for me. Mainly stock as far as i can tell.

 

you could try hooking dist'r vacuum can to manifold vacuum, then retarding the timing to where it is happy, and see how that behaves overall. The cost is right about zero.


This configuration was quite common before 1968.

"normal driving between gears" I interpret as not accelerating therefore the accelerator pump and associated parts are unrelated.

 

So, you're saying that you're angry because it may have its original engine?



Which is generally the effect of disconnecting the vacuum advance, more or less.



I usually try to drive with the car IN gear - the engine makes a lot of noise between gears, but the car doesn't seem to go anywhere.

- Eric

 

Not angry about it being the original motor. Actually happy about that. I bought this car as a mostly original car have build sheet highly optioned car was at a somewhat local collector car dealer. What kind of ticked me was someone actually gave the previous owner a bs story about it being 455 and rebuilt the original. My good luck was the people at dealer didnt do homework check block numbers so i kind of won for a change. As far as normal just stepping on the gas to go between first to second it takes a second for it to get gas. Just not a smooth transition if that makes sense.