Vannin' Home Forums Chevy Performance (GM) 350 carbs

I have an older Holley carb on my 75 350 engine, and it looks like I'll need to replace it very soon. I'm not too mechanically inclined, so I got a local mechanic to look over my new acqusition. He said that the "accelerator pump is bad, and the carb loads up at idle". Would I be better off getting a rebuilt carb, or a new one? I checked the cost of a rebuilt (about 170 bucks) versus a new Holley (about 420 bucks), so there is a finnacial incentive for going rebuilt. What about performance and reliability?

Also, how do I tell if I have a th350 or 400 tranny? Thanks!!!

Unless you need some serious performance.......stick with the Q-jet. It's the "set it and forget it" carb!

TH350's pan shape is a square with a corner cut off.
TH400 is kinda like "Texas"

------------------
"Laissez Le Bon Temp Rouler' Cha!"
Chevytalk Moderator
GMforums Moderator
Vannin Guru
"Jungle"Jim
70SS396 & 70 Malibu
My Car
"I don't drive FAST, I just FLY low!"

Thanks JJ! I spoke with a couple of people yesterday about carbs - their spin on it was that Holley has had some problems in the past (these may be addressed by the new line of carbs), but that Edelbrock is the preferred choice - for these folks, at least! They mentioned the Quadrajet, and said that it's very reliable, but more of a beast to rebuild. What about the two-piece carbs? I am not looking for serious performance (not more than 350 hp, most likely), and I will get a lot out of the engine rebuild down the line (cam, lifters, intake maifold, new headers, etc...). Whichever carb I choos for the present engine configuration, I would like to transfer to the new engine setup.

I agree with Jungle Jim, stick with the Rochester Q Jet, they last forever and are easy and dirt cheap to rebuild, I have no idea where the advice you got came from, my first carb rebuild was a q-jet and they are much easier to work on then any Holley I've ever owned.If you decide to go with a Holley in your van a 450cfm Model 4160 is a econo solution,direct replacement for the Q-Jet, has emissions setups on it if you have to use them in your state. A 600 is a perfect performance choice for a stock 350.I've owned 8 Chevy vans and have used one or the other on all of them .My 79 Chevy Van has a 650 Holley with a weiand hirise intake and it flies, unfortunately past everything but a gas station.Stick with the Q Jet tho if you want to spend a min amount of time under the hood plus you'll love the distictive wahhhhhhhh noise it makes when the secondaries kick in hehe.

Yeah, that great sound is cool! You sure can't get that on a lot of modern engines!! The folks at my local Trak Auto were the ones that mentioned the Q-jet being a beast to rebuild. The one they specifically mentioned was the Edelbrock - I am familiar with some of the different body makes, but I didn't know Rochester had a Q-jet. Or do several companies have Q-jet carbs? The idea of "set it and forget it" is very appealing!

The original Quadrajet was built for GM products and was manufactured by Rochester. Edelbrock, Weber, and others make carbs that fit those applications but Rochester made the "Spread bore" Carb originally.Holley makes a couple of spread bore carbs that fit
Quadrajet applications.I worked part time in a Carb Wholesaler in Denver a long time ago while in the Air Force and we used to sell lots of carb parts to people that moved to Colo. and found their vehicles wouldn't run well at that altitude without being rejetted. In fact, one model of Honda Civic Cvcc wouldn't run at all there without radical mods!! Unless you're planning on racing go with the Rochester,it'll probably outlast the vehicle you put it on.