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Here's my setup I have an 86 Firebird with a 79 350 out of a Chevy G20. It has the vaccum advance distributor and the quadrajet carb. With wideopen acceleration it hits about 4k rpm and it's like the car stalls and the rpms drops off until they come down to about 1k. It's almost like an electronic rev limiter kicks in an FI car. I'm thinking it's either the fuel pump or in the carb.
When was the last time it had a fuel filter?
just changed it earlier in the week and set the timing to 8 Degrees btdc
Could be a small crack in the fuel pump diaphram causing the fuel to airiate,,,or just plain cant keep up with the fuel demand.
Good idea to swap out the fuel filter anyway's.
I don't remember if I used the fuel pump off the the 350 or the blown 305 that was originally in it. Is there a difference? I didn't think there was, but maybe I'm wrong
Depends on your carburation CFM,,,you may want to put in a higher volume pump.
I never really thought about it, but that would make sense. It never had this problem before, but before it was way out of time, and needed a fuel filter so then again it didn't run this good (until 4k on the tach)
I just cross referenced the part numbers and the fuel pump for a 79 350 is the same for an 86 305
It does sound like you do have a fuel starvation problem. Couple of other places to check.
The rubber fuel line that connects the tank to the steel fuel line on the body, and the steel line on the body to the supply side of the fuel pump. A crack in the rubber hoses will cause air instead of fuel to be drawn and may not necessarly result in fuel leaking.
If all else fails pull the pick-up out of the tank and check/replace the screen on the end.
Just by chance, could the thing have an external fuel filter plus the one in the carb inlet....and you are changing the external filter? Mike P makes sense when he points to the filter.
When the thing slows down, does it eventually recover and run decently?
just has the one internal filter. If I give er hell for all she's worth is when this occurs if I let off and let it recover then it runs fine. It runs strong in town it'll even break the rear end loose going into 2nd. But when it's out on a stretch and it begins to tach out is when this happens
Sounds like a volume restriction/limit
dirty sock on pickup
squished area or kink in line or hose
weak fuel pump
break allowing air to be pulled into/thru pump
fuel filter not flowing
low fuel volume in bowl
I'm going to check all of that. It didn't do that until I set the timing, and changed the filter and air cleaner. I'm just hoping it's not in the carb. I don't the cha ching for that now
it had a short one in it, but all the parts catalogs called for the long one so I put a long one in it. I'm not sure about the check valve all I know is that it had a rubber hole on one side of it.
It acts almost like it did when the choke was acting up. I did notice tonight that it seems like it's doing between the 2nd and 3rd shift when it's wide open
was the carb originally on the g20? maybe a little dirt in the float area causing it to stick partially closed. my 1980 olds sat for 6 months and was doing exact same thing alittle tapping on the carb and 2 bottles of heavy fuel system cleaner fixed and runs fine