Carb, what should I do?
 

I just acquired a 1970 Form-400 with complete #s matching drive train. The one item missing is the original carb. The carb that is on there now is a 702826 / 0734 Quadrajet. This 1968 Pontiac carb is in need of a rebuild it appears. My question is; is this carb a good candidate from a performance perspective for a rebuild or should I search for a better candidate such as a 7040....... carb that is correct and perhaps a better performer? Thanks

Send Cliff R a message….he will tell you the answer

Would this one work?

Its and original from my 70 Formula but a gorilla worked on it before I owned it warping the airborne and breaking off a accelerator pump arm support it's a shelf item

Hard to find

hi, the 68 carb is a 750cfm as would 7040*** in 1976 they started making 800cfm carbs. I have a 17057253 olds carb im building for my TA. they are better in alot of ways but the 750 might be just fine for what your doing. and yes cliffs high performance is the way to go. been buying parts from him for many years. he also will talk to you and set you up for your needs. good luck, BLUE TA

Cliff Retired?
 

Cliff did my carb for my 1970 T/A a few years back and did an excellent job. I thought he was retired from the business though?

Nope, still alive and doing those Q-jets. I believe he's mostly doing parts and making up kits for people to build their own Q-jet. Give him a call to see what's currently happening.

https://cliffshighperformance.com/

from a performance standpoint, as I have understood it, the 1968 carb might be better;
if not better, then exactly the same.
The 1968 Quadrajet will not have POE, and will be setup to run a smidge richer than a non-RA 1970 carb.
The 1969 & 1970 Pontiac Quadrajets with PEO permitted slightly leaner settings, which in turn should make them a bit better on fuel.

I am sure that this doesn't needed to be mentioned, but in 1970 there were 564/563 carbs for California (and maybe some Pac-NW) destined cars, while the others received the 264/263.

Honestly, if it were my car, I'd get a correct carb - even a service replacement unit is more "correct" than the 1968 SR carb you go;
But on the flip side I'd wager that 98% of the people who would see your car wouldn't notice it's the "wrong" carb - so it's really all up to you.

I think Cliff just made note in commenting on another post today that he no longer rebuilds Carbs, just sells parts, none the less I would double check with him on that.
I see nothing wrong in rebuilding and running g that Carb unless your into having everything original.

I would do it top to bottom with installing primary throttle shaft bushings even if it does not need them now, as this will keep you from having to find a hard to dig up good throttle shaft!

Other items if they show ware also like the secondary metering rod Cam should get replaced at rebuild time also.

A “”later model 800 cfm Carb will by you hardly any additional power if your only running a factory Cam in the motor .

I would not consider running a later 800cfm carb on a car that is otherwise completely number matching;
Doing this will mean that you cannot run the original aircleaner, unless you find a later divorced choke chevrolet truck 800cfm unit - and I don't believe those were ever made with the front faceing fuel filter housing.
(The few post-1975 Chevrolet front-fuel-filter quadrajets I have seen were all big block 750 cfm units.)

I'd stick with the 1968 Pontiac carb that's there, or get the correct application unit.

As to replacement throttle shaft bushings;
Just a word from what I have seen;
These installs can go wrong and end up making matters much worse.
I have a 1973 400/4spd carb which the primary throttle shaft had seized in the replacement bushing - when I un-seized it, the bushing came out with it.

I would honestly play throttle shaft bushings like well plugs - if it's fine, leave it alone.

I would send your 1968 carb to Jeff (Shaker455) and have him dial it it for you on an engine before sending it back to you.
He has done lots and lots of them over the years and is still rebuilding carbs. Was not aware Cliff stopped building carbs.

Thanks

Tom V.

Thanks
 

Thanks for all the great input Gentlemen. I will probably have my 1968 unit rebuilt locally here in FL as I do have one good Carb shop that is highly regarded by a few customers.

Cliff will sell you a decent rebuild kit..