Hey a buddy of mine has an '81 Chevy with a .060 over 454 in it... Old school, no computers or anything. Sometimes at around 4k rpm it just cuts out for a bit, then starts pulling again, till it gets back up to around 4k, then it'll cut out again. This problem isn't there all the time, just every once in a while. Any ideas on what might be causing it? We think it might be starving for fuel, maybe have some nasty crap in the bottom of the tank or something, or maybe a plug or two has some cracked ceramic and it's shorting out. Here's the whole setup so you'll know what we're working with: 454 bored .060 over, ported stock heads with exhaust valve punched out to 1.88", Edelbrock Performer RPM cam & air-gap intake package, Edelbrock 800 cfm manual choke carb, Edelbrock Performer RPM mechanical fuel pump, stock distributor with Accel self contained coil-distributor cap, Dynatech Ceramic coated headers and dual 2½ inch exhaust with 40 series Flowmasters. Don't know what year the block and heads are... I assume early 80s... The truck originally came with a V6 but the guy bought the engine out of an old farm truck that sat in a field for a while. Any thoughts on what might be the problem would be appreciated... This tends to be a bit of a nuisance sometimes. Thanks guys!

 

It sounds like a timing advance problem, check out the vaccum advance and the springs under the rotor, also have the module checked out. It might not hurt to replace the module to coil wiring harness, I've worked on a trans am where one of those wires was broken in the insulation.

 

I would do the obvious tune up, cap, roter, plugs, wires, and coil. I would also change the fuel fileter and check the bowl on the carb check and see if there is any trash in there. While you are at it check the timing advance. If it were me I would make a trot line weight out of that carb and put a holly or a barry grant on. I think if you do all of that you will find your problem.

Dock

 

I'm with dock rocker on the Edelbrocks. They are just a Carter AFB rebadged. I don't care for them personally. It sound like you have a problem with the mechanical or vacume advance in the distributor. Sometimes the wieghts can get hung up or the springs stretched. It could be a starvation issue. Just for thought. most older gm's came with a 5/16" line coming from the gas tank if it was a 6 cyl or small v8. Most 327 and larger vehicles came with a 3/8" line. That could cause a restriction on the 468 you have there. When it dies out it may have enough time to fill the carb bowl to allow it to pull again. I'd start with the simple things first like has been mentioned with the timing advance and the fuel filter.

 

just for thought. most older gm's came with a 5/16" line coming from the gas tank if it was a 6 cyl or small v8. Most 327 and larger vehicles came with a 3/8" line. That could cause a restriction on the 468 you have there.


That is a good idea. I would have never thought of that. I would put a fuel pressure gauge on it as well that would point out a problem it it were there.

Dock

 

Ok, nevermind all this nonsense... He found me the other day and said he had used quick-disconnect fittings for some of the electricals... One was loose is why it did this. Man, I felt like a REALLY smart guy after that... Course I didnt know about the Q-D's either.. Oh well.