1984 Chevy 350 still being a headache to get running right

[grandall1972]

"Revs while parked well"

How about when you stomp the %#*% out of it and hold it WIDE open. If it revs good--like the motor will blow up if you stay at it-- then look for something else- rear end locking up?, trans?, brakes?, wheel bearing?, etc.

rear brake was locked up some but we’ve fixed that. Axle spins fine. Unless it’s a 1:1 rear gear it’s not the gearing robbing that much power on stock wheels and tires.

 

[grandall1972]

A few random questions. Is the fuel tank vented. ? go drive it with the gas cap off and see if it runs better. Also look at the new fuel lines and make sure there are no kinks or squished lines. Follow it all the way to the tank. You could have high fuel pressure due to a restriction. Is it smoking ? color ? how do the plugs look ? what color ? gapped in specs and right heat range ?

00"]

1. Is the fuel tank vented.
- yes
2. go drive it with the gas cap off and see if it runs better.
- Drives same
Also look at the new fuel lines and make sure there are no kinks or squished lines.
- Mechanical fuel pump so pulls gas from tank but distance to carb is very short and pressure measured going into carb.
3. Is it smoking ? color ?
- No smoke.
4. how do the plugs look? Color and gapped
- first set were pretty black pretty quick but the choke was not powered correctly and was getting no air. Haven’t checked the second set since putting them in but may check once I get some more starts on the. They are AC Delco factory style, and gapped correctly.

 

[Kyzrsoze]

00"]

1. Is the fuel tank vented.
- yes
2. go drive it with the gas cap off and see if it runs better.
- Drives same
Also look at the new fuel lines and make sure there are no kinks or squished lines.
- Mechanical fuel pump so pulls gas from tank but distance to carb is very short and pressure measured going into carb.
3. Is it smoking ? color ?
- No smoke.
4. how do the plugs look? Color and gapped
- first set were pretty black pretty quick but the choke was not powered correctly and was getting no air. Haven’t checked the second set since putting them in but may check once I get some more starts on the. They are AC Delco factory style, and gapped correctly.

A friend of mine had a 72 Silverado that was rebuilt to a similar level. His was starving for fuel and destroyed the the mechanical fuel pump. The problem turned out to be an old section of rubber fuel line under the cab. It collapsed under load and drastically restricted flow.

...I'm still thinking you need a carb wizard.

 

[sniper22]

I'll say it since I haven't read no one else saying it. The vacuum leak will make a big difference when in the power curve. It should be able to handle the fuel pressure but it sounds like its being restricted when its calling for a "dump".
Check and clean the grounds for the battery and distributor. That will cause you more problems than everything else combined.

 

[Kyzrsoze]

...still brainstorming, is the choke manual or electric - and is it set up properly?

 

[Toothlesswun]

750rpms

Then it doesn’t have a vacuum leak, is the fuel tank new and are you running a clear fuel filter near the carb?and what transmission does it have

 

[fslc94]

carb is an edlebrock 600cfm.

Thats 80+90% of the problem...Edlebrock carb. Hate’em!

 

[sniper22]

Thats 80+90% of the problem...Edlebrock carb. Hate’em!

I'd rather have a quadra bog..

 

[grandall1972]

Then it doesn’t have a vacuum leak, is the fuel tank new and are you running a clear fuel filter near the carb?and what transmission does it have

New fuel tank and sending unit. Not a clear filter though, but right before the carb. Fuel pressure was checked after fuel filter. Has the SM465.

 

[Toothlesswun]

New fuel tank and sending unit. Not a clear filter though, but right before the carb. Fuel pressure was checked after fuel filter. Has the SM465.

If you hold it wide open throttle, does all four barrels open up? Is the trans a turbo 350? have you checked vacuum supply to the modulator?