[BlownBirdy]

***Let me apologize if you read this twice, I put it in Hotrodding Basics on accident too, sorry.***
Hey Guys,
At work I have become friends with an older guy (retired mechanic) who has owned a 1976 Pontiac Bonneville 2-door hardtop since it was brand new. I guess it was one of four hundred which makes it a pretty cool car. Besides the timing chain and normal wear items the car is completely stock. It has a Pontiac 400 S in it and just turned 170,000 miles. This is a daily driver, not designed to be raced or even beat on. It gets him around town and is mainly a cruiser. The factory q-jet is starting to get tired and after quite a few rebuilds is starting to get more and more finicky (Runs rich even after adjustments, bogs a little, etc.). The guy really knows his way around an older engine and his rebuilds are COMPLETE with floats and rods and needle/seats, passage cleanings, the works, but we figure the carb just might be getting worn. The time it runs good before each rebuild is less and less each time. We are thinking of replacing it with a more modern carb but I figured why not get your input before so. I guess at one time he tried a Holley Economizer or something like that which I have never heard of but had problems and went back to the Q. He likes the Q but wants to see what else is out there I suppose. We are in Phoenix so altitude isn't a critical factor and the car weighs a few tons and has street gearing so I figure vaccuum secondaries are a must. We are not trying to get crazy performance, just a reliable carb that gets decent economy for what it is on. Not changing the intake so the carb needs to be spread bore. Any thoughts? Thanks a bunch.

 

[tbirdscott]

The holes in the intake for the primaries MAY be tiny for the Q-jet so you might not be able to bolt on anything other than another Q-jet without getting a new intake.

I've seen new Q-jets in the summit catalog, might be the easiest route.

 

[willowbilly3]

Holley makes a bolt on spreadbore in a couple different sizes. I had one on a 442 400 and it worked perfect except it always needed new gaskets after it sat for a while.
Part of the problem with the old Qjet may be the secondary metering rod orifices. They tend to get wollered out after a while. Also the throttle shaft needs rebushed if it has never been done. Due to the way they put the return spring pulling in the same direction as the throttle cable it is more of a problem on Qjets that other carbs. Many people will also tell you the well plugs on the bottom of the fuel bowl need resealed. I don't think it is as big of problem as it is made out to be but it can't hurt to do it. The bogging maybe something unrelated to the carb.
The economizers was Holleys attempt to capitolize on the high fuel prices of the oil embargo days of the 70s. When it worked right, and it seldom did, there was a signifigant loss of power from a stock carb. Junk