78 w72 carb substitute
 

Hello,
First post on the forum in a long time.
I would like to know what would be a good substitute for my original carburetor. It’s a stock w72. I would like to shelf the carb and get a replacement for driving.
Also an exhaust system and tires for 15x8 snowflakes.
Any recommendations are appreciated.
I would like to get it in driveable condition
To enjoy. Thanks!
Brad

Shelf the carb? Seek out a regular Quadrajet for a Pontiac if can't find the matching carb, rebuild and rejet to suit your setup. Stock W72 isn't anything terribly fancy, you can easily cover it's needs. But if you have the correct carb already, everything just fits where it should.

Hey Brad, I have 78 TA W72 - I originally rebuilt the stock 400 and used Summit 2801 cam and headers. I used stock intake and stock 78 W72 quadrajet and ran fine. I converted the 400 into a stroker - but kept stock intake and quadrajet. The 78 W72 qjet is 800cfm and a good carb. I would try and rebuild the carb yourself. It is not too hard. The carb can often benefit from a good cleaning and some new parts like float. For parts , I used https://cliffshighperformance.com/ , a bit pricey but the parts are top quality. Cliff also publishes great book on rebuilding - setting up a quadrajet.
.
For tires, 255/60/15 fits nicely and looks good - I have 255/60/15 Yokohamas, though when I replace will likely try Cobras
https://www.tirerack.com/tires/tires...omCompare1=yes
.
For exhaust
https://www.summitracing.com/parts/s...model/firebird
https://pypesexhaust.com/c-702350-gm...-trans-am.html

Tyres/wheels and exhaust can be a personal taste thing. It can be hard to make suggestions especially if you don't know what you are after. What one person said is perfect, another will hate. Likewise, if you like all 4 tyres being the same or having wider on the rear will at least be a start.

But here's some ideas of tyre/wheel suspension combos:

http://www.transamcountry.com/commun...?topic=83572.0

Great!
Thanks for all the information and the links.

I have a W72 carb up for sale

lots of options for a pontiac q-jet that will work for a stock W72, same basic carb on the non W72 firebirds & other big car engines from 76-78, you can find a good core for pretty cheap to rebuild on ebay or other forums & online sources, or check with one of the companies that rebuild q-jets, they probably have a nice stock type carb for a good price. SMI is a good option.

here is probably the best priced rebuilt carb with a cliffs kit out there, & its even a W72#. cant beat the price for this, less than half the price of what some others charge...

https://forums.maxperformanceinc.com...d.php?t=859440

tires: 255/60 are close to stock height but a little wider, 225/70 is factory size. M/T ST radial are a good alternative to BFG & have a higher speed rating & dont have white letter issues that some sizes of BFGs have lately.

exhaust, summit makes a lower priced kit or look into pypes kits. but for basic low hp, a local exhaust shop can make & install exhaust for cheaper than buying a kit & paying them to install it.

The stock Q-Jet was a good piece, but the fuel curve is lean stock, to satisfy the emission regs of the day. The idle circuit will need some work, and obviously rejet and rods.

Cliff sells 3 different kit choices. It may be necessary to use the highest end kit. If one is doing much tuning. Cliff put together the lowest price kit to give folks a choice, if they just prefer a “ parts store” type kit.
I’ve always bought the most expensive of his kits. They have parts that almost no one else even sells, or have a clue, what they are or how they work. Cliff supplies service after the sale. eBay does not...

Often the difference between rebuilding a carb to stock, even if it was stock on a different engine and setup, or rebuilding it to suit your actual requirements.

Generally an early 73 ish Qjet is going to have a little better idle down tube size than the lean 78s, so if any cam upgrade they will idle much smoother and not have main booster "drizzle" with throttle blades open too much to get it to idle.

I put a 73 SD SR carb on mine with a mild cam upgrade and it was a world of difference. Have a 73 "regular" 750 Q jet on the 81 400 and it idles well also.

I got a carb for my T/A. Problem is the throttle hook up lever is wrong for my stock w-72.
Also the baseplate is wrong.
Anyone have these parts?

Thanks in advance!

Holley makes studs for the throttle and TH350 downshift cable I have added them on Holleys as well as 73 carbs.

Thanks!
My whole lever Assembly is different. The stud doesn’t line up to the lockdown cable. Also the return spring is different. I think the lever assembly is from an olds or Chevy. Not a Pontiac.

Carb number and/or picture might help us, help you...

Both carb numbers are 17058266.
So the differences between the original carb and the one I want to run on the car are.

1. New carb has a different throttle lever Assembly.

2. New carb has a smaller vacuum port on the back for the brake booster etc.

3. New carb doesn’t have a vacuum port on the front passenger side baseplate for a small vacuum line.

Looks to me the whole baseplate was switched out from another carb.

So is what I’m looking for is the correct baseplate for this carb. And I also need the vacuum fitting for the back if someone has an extra.

Agree^
This is a post builder thread, just get the rite carb, you an get a rebuildable CORRECT CARB at a reasonable price, then rebuild it. There were plenty of carbs at Dayton.