I have a Chevy 283 that came in my 68 Chevy pickup shortbed. Why does it seem like it has no power?

Question

My Chevy C10 shortbed has a 12 bolt rear end geared pretty low. 4.11? I was told by the guy I bought it from that the 283 cci had been rebuilt right before he bought. He only had the truck less than a year and was selling it to me. I have no reason to doubt him, but the 600 Holly, Eldebrock intake, dual exhaust, HEI distributor with racing cam, it just doesn't seem to have any git up and go like it should. At one point, I was talking to Summit Racing tech line about the possibility that someone had put in the wrong torque converter. The tech person at Summit didn't think so. He said since I frequently smelled gas when I pulled in the garage, he thought I should be looking at the 600 Holley as the cause of the problem. He said something about gas leaking into the secondaries and how to close them off. I am not a Carburetor wiz and I couldn't follow his advice. Anything I can do besides save up my money and try a new carb? (Only to find out that may not be the problem?)

Answer 1

I'm curious about a few things.

1) What type of secondarIEs are on the carburetor?
Vacuum or mechanical?

2) Have you checked the basics?
ie; Air filter, fuel filter, ignition timing, engine oil, coolant?

3) How well does it accelerate under moderate (half) throttle?

What happens when you "floor it"? Can you hear the secondaries open up slowly, or do they open up immediately?

Answer 2

FIRST of all, find and fix that fuel leak, or you will someday have a burned up truck, and house too.

Start with the basics. Check the timing, ignition parts for wear, make sure the vacuum advance is working, see if the carb secondaries are actually opening when asked to, make sure the rockers are not adjusted down too tight if it's a hydraulic cam. You should check the cam timing too, bit it requires some engine dis-assembly, so do it if all else fails.

Do you have a restrictive single exhaust system? Get headers and low restriction mufflers if you don't have them now.

Good luck.

Answer 3

First check your compression.. you could have a burned valve or valves.. if your compression is good then check the throttle valve.. it could be flooding itself if the carb is overloaded with fuel... also you could be running to rich.. check your mixtue setting and try to lean it out some.. you should be able to tell if you are running rich by removing each sparkplug to check for carbon on the tip.. also check inside the tail pipe.. see if you have carbon build up on the inside... in a fourbarrel carb.. you have the primary jets that feed fuel into the two main barrels.. and secondary jets that kick in and feed fuel to the two smaller barrels... when you get on it.. I am not familiar with the carb model that you have..but I would think that you can shut the secondary jets off some how.. most parts store guys can tell you something about it.. if not.. five will get you ten that they have a customer who can.. if you can't figure it out.. go to the parts store and ask them.. thats what I do.. most of the time they have a pretty good answer.. good luck

Answer 4

You have too much slack in your timing chain.
Put a new timing chain and timing gear on and set the timing at 4-6 before tdc

Answer 5

If the engine timing is not set up right the engine will be
sluggish, if you have a carb problem, it will do the same ,
but it will also be hard to start.