Carb struggles (1 Viewer)

[AF-40]

Hi, I'm looking for some help. I've got a '72 with a Chevy 350 crate engine with mods that was completed when I purchased it last summer (about 6000 miles on the entire engine swap. It has headers, K & N filter, SM 465 trans mated to TLC transfer case with Marlin gears inside, 4.56 gears and positrax units in front and rear also. It has a Weiand intake manifold and Holley 670 cfm Avenger carb, electric fuel pump with dual filters. I've had intermittent trouble with the carb, had it serviced and rejetted several months ago and now it's acting up again. Has electronic choke which I suspect but it runs terribly and wants to die at idle. But the problem is on and off again. I've added a couple cans of Berrymans to see if it might be the gas. I just don't have enough experience and hesitate to take it back to the same mechanic as I'm not confident he will be able to fix it and don't want to pay him any more money. Does anyone know a good mechanic in Ft. Worth area who they feel might be able to diagnose and fix the problem?
I've looked into EFI and understand that would be a great fix but I don't have the money right now to do such a swap. (And if I were to do such a swap what might you suggest, TBI? and where would I get one?)
Sorry for all the questions, just nobody I know right now has any good answers. Thanks for any help you can give me. Frank

 

[Pin_Head]

I don't have much personal experience with Holley carbs, but I remember that they made a decent carb for wide open throttle applications, like mud bog racing. It seems that a lot of people have problems with them off road, so you can search pirate4x4.com for more info. They also have a tech hot line and web based trouble shooting.
http://www.holley.com/HiOctn/TechServ/TechServ.html

 

[honk]

Do you smell gas when it runs bad?

Things like this can be goldmines for some mechanics...the diagnosis time will eat you up. I'd try a fuel pressure regulator, one of those Purolator kinds with adjustment from about 1 to five psi. Try running it at two psi for a while. The electric fuel pump might be overwhelming the carb needle valve.