I am currently running a stock 350 2bbl with a Petronix Ignitor Ignition in a stock GM distributor. My mechanic has a rebuilt Holley 750 he wants to sell for $150. I happen to have a Edelbrock P4B to bolt it to. I also have a MSD Ready-To-Run distributor and coil.

My main concern is - is this too much for this stock engine? My transmission is stock 350TH w/ a B&M shift kit. Stock differential 2.73 gears (non-posi).

Thoughts?

Double Pumper or vac. secondary?

I believe it's a double pumper. And I am assuming that would make a difference? (I'm kinda dumb about carbs)

Its not to big, but you'l probly have to put smaller jets in it unless he already did.
Most Holleys are to rich for stock engines.

I have the Igniter ignition and a flame thrower coil. It has not missed a beat and the car starts the instant it is turned over. I'm not sure if you will notice much of a performance increase with the MSD altho I think there are more options available to tweak it. Anyone else??

Way too much carb for a stock 350 and highway rear gears. If you're going to convert to 4 Bbl with that setup you would want a 500 cfm carb. MAYBE a 600.

If you put that 750 on, your mileage will go to zero and you will be chocking on your own exhaust all the time.

Vacuum secondaries are more forgiving. You can run a bigger carb than necessary and not have as much driveability issues. If it's a 750 CFM DP for your 350 , I'd pass.

I concur entirely with this opinion...

PS I have an Edlebrock 1406 (600cfm) w/ elec choke that is currently on my 326 LeMans. It's a great carb and runs EXCELLENT. I'll be listing it under the for sale section in two weeks as my mighty 400 goes in the week after next. This carb is currently bolted to an older edlebrock alluminum intake (painted the correct Pontiac engine color) and will also be for sale. This would be an excellent combo for your particular engine and would be a direct bolt on and go, all you would need is a new set of intake gaskets, that's it!

My LeMans runs incredible with this setup and I am now getting 21mpg with the 4-speed in place and the 2.56 open rear.

Ditto

All Pontiac q-jets where near 750 cfm from 68-73 or 74?.
74(or 75?) and up where 780 cfm. Some say 800. Yes, on low performance 350's. EVEN 77-81 301's!
If its a dbl pumper, probly have to get smaller pumps too.
I would use q-jet myself.

It took me 2 years to get my Q-jet properly adjusted. Now that it is, I would recommend it as well.

Until I understood how the thing worked, adjusting it was a lessen in futility.

Don't forget the factory limited the secondary opening on some of the applications for performance/emission reasons. Doing that does effectively change the CFM rating. My motor was a stock 350 2bbl and I put on a stock 68 4bbl manifold and a 69 Q-jet from a Buick Wildcat that had a 430cube and have the secondary linkage adjusted to 90 degrees at WOT. I think I have it dialed in as best as possible and the motor is handling it just fine. With the occasional running out of fuel at the top of first gear, but that's a separate issue.

Keep in mind that the Q-jet is a spread bore while the Holley DP is a square bore. That being said, a 750 Q-jet's primary opening is smaller than the Holley. While you are going down the road under light throttle, you are effectively working from a smaller carb than the same throttle on the Holley. They are not apples to apples when looking at CFM rating. That is how much they flow when the throttle is pegged. You will gain in overall power vs the 2-barrel, but your driveablitly will certainly suffer. If you want the holley, I would go to the 600cfm. Vacuum secondaries if it is an auto and/or you have highway gears, mechanical secondaries (double pump) if you have a manual or steeper gears.

I had my original Q-jet professionally rebuilt, plated and adjusted by a guy in Edmonton who specializes in them, he did a beautiful job and it ran perfectly right out of the box, plugs are perfect colour and does not miss a beat. He test ran it in the shop apparently.

I'm very happy with it and the gas mileage, and performance when those big secondaries get a workout....

Q-jets were used on the OHC 230 and 250, Buick 252 and other small engines despite the 700+ rating. The limiter was to satisfy the 10 lbs/hp edict from head office at the time.