Thread: carb question

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I have a stock 472 out of a 71 caddy hearse. In exchange for delivery i gave him the carb for his project. My question is what cfm carb do i need?

There will be other replies, but I would suggest a properly rebuilt Quadrajet designed for that size engine.

Edelbrock now has intakes for the Caddy 472-500 part# EDL-2115 that and EDL-1411 Carb would make a good combo

thanks guys

I think NTFDAY and JeffB2 hit it on the money, the EDL 1411 is a 750 CFM carb.
I think thats perfect for what you are gonna need with that motor.
Kurt

will that carb bolt up straight to my stock intake?

That I am not sure but if you call Edelbrock they could tell you.
If not they probably have a adapter plate for 10 or 15 bucks.
Though the intake Jeff recomended would make the motor
perform alot better then the stock intake would.
But that is $$$ you realy don't have to spend.
Kurt
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Barb, the Caddy had a quadrajet on it originally and that one has a different bore pattern than Edelbrock or Holley square bores. Adapter plates are available and Edelbrock (and maybe Holley) make carbs with the q jet pattern, but they are pricey.

Cheapest alternative is to put another q jet on it. Some people love em, some hate em, and I personally have no problem with them. They have been used on a ton of factory cars over the years and almost every marine v8 engine is running one (until efi came on the scene). If you decide to go that route you can find them in junkyards (get one without all the vacuum ports and emissions stuff), or, there is a company in Jacksonville Florida that sells rebuilt one outright on Ebay for about $ 200.00. My Son Don just ordered one for his boat and it was about half price over what Summit and others get for theirs.


You can even use one from like a 454 boat engine, they are identical to car versions but have a different vent tube to prevent explosions in an enclosed bilge area, but in a car they work the same.
Don

Hey Don Could she make a spacer plate out of 3/4 plywood like
I used to do for my Holleys. She would have to get some longer studs for the intake.
Kurt

the cadillac 472/500 quadrajet actually is a bit of a special quadrajet that is highly sought after because it can increase MPG... not that any old Q-jet won't work, that 1 would probably be the best to use.. IIRC it's an 800 CFM model.

another option is a Holley quadrajet replacement carb.., don't know what CFM's they come in tho.. but I'v seen them from time to time on Ebay for $30 or so needing rebuilds

I think the carb fits close behind the a/c compressor on those engines so on an ac car----you should stay with q jet

thank you so much guys. i am going with the matching edelbrock intake. that seems to be the safest way so i won't mess up. got the new tranny for it today. guy locally was going from a 454 to a 383 so he wanted a good th350 in exchange for his 400 with 3000 stall. gave him mine out of the monte for a even swap. so now i can use the tranny money for the intake.

Kind of Bad news Barb, the Chevy tranny has a different bellhousing bolt pattern than the Caddy motor. An Adaptor can be used to mate the tranny to your motor but some people discourage that due to the amount of torque the 472/500s make.

Also unless you want to spend a bunch of money making the Caddy motor really spin some RPM the 3000 stall is going to be a bit loose. The Caddys make torqe way down in the RPM range (2000-2500 RPM) and in stock form float the valves at about 4200 RPM, although 5000 is doable with some better springs. RPM levels above that really require an after market valvetrain which can start to get really expensive. A 3000 Stall convertor will probably do nothing more than let you do REALL impressive burnouts.

thanks pat. did not even consider that the bolt pattern would be different. the 472 came ith a tranny attched but it is way too long for my application. i guess time for more horse trading.

You can Run that Long Tail 400 Trans if you have your Drive shaft cut down . Anyway you need to change that Front Drive shaft Yoke . I think the Edelbrock 750 carb would be cheaper and more trouble free then a Q-Jet . The Q-jets are good Carb's but they are not with out Problems .