Mid 70s Quadrajet 7045213

[james Kekeisen]

I'm trying my hand at my first carb rebuild. The subject carb was given to me so I've decided to give it a whirl on my 69 350/350. I picked up Doug Roe's book on Rochesters to assist in the rebuild. My question is probably stupid but here goes.

The carb has a place for the hot-idle compensator on the back of the carb however there is nothing in the space and no cover. Roe's book says that "some Q-jets don't have them". Does he mean that there may be no space for one at all or does he mean there doesn't need to be anything in the opening (ie the bimetal valve). Until I read that quote I assumed the bimetal valve and cover had been removed and lost. Does it need those parts to operate? Can the bimetal valve and cover be purchased separately?

thanks, Jim

[Joe L.]

Re: Mid 70s Quadrajet 7045213

Jim-----

Have no worry. If the valve and cover are not present, they were probably never there to begin with. Many Rochester Q-Jets have the cavity in the rear of the float bowl casting for the valve, while not having anything ever originally installed. Very often, Q-Jets which have the idle vent on the top of the front of the air horn casting (as evidenced by the little zinc plated, stamped steel rectangular box-like cover), will not have the valve at the rear of the float bowl. Those Q-Jets without the idle vent on top of the front of the air horn will have the valve installed at the rear of the float bowl casting.

[Joe L.]

Re: Mid 70s Quadrajet 7045213

Jim-----

Have no worry. If the valve and cover are not present, they were probably never there to begin with. Many Rochester Q-Jets have the cavity in the rear of the float bowl casting for the valve, while not having anything ever originally installed. Very often, Q-Jets which have the idle vent on the top of the front of the air horn casting (as evidenced by the little zinc plated, stamped steel rectangular box-like cover), will not have the valve at the rear of the float bowl. Those Q-Jets without the idle vent on top of the front of the air horn will have the valve installed at the rear of the float bowl casting.

[Jack H.]

Amen!

The Q-Jet book starts by telling you this was one of the longest running basic carb units in automotive history. But, most try to force the book to show specific pictures/proceedures for their specific form of Q-Jet. That's beyond the realm of possibility with an omnibus book....

Joe's right, if you see an indent in the casting, it doesn't mean that feature was originally there on your carb. It may well be 'vestigial' to the generic Q-Jet family. Secondary operations (drill, tap, Etc,) dictated the specific appearance and feature/functions on a given carb.

But, my recollection is fuzzy now. I'd have to check the original post to see if you actually have the correct core for your year Corvette. Seems there was a '4' or '5' in the PN sequence where we'd expect a '9' for a '69 carb.....

[Jack H.]

Amen!

The Q-Jet book starts by telling you this was one of the longest running basic carb units in automotive history. But, most try to force the book to show specific pictures/proceedures for their specific form of Q-Jet. That's beyond the realm of possibility with an omnibus book....

Joe's right, if you see an indent in the casting, it doesn't mean that feature was originally there on your carb. It may well be 'vestigial' to the generic Q-Jet family. Secondary operations (drill, tap, Etc,) dictated the specific appearance and feature/functions on a given carb.

But, my recollection is fuzzy now. I'd have to check the original post to see if you actually have the correct core for your year Corvette. Seems there was a '4' or '5' in the PN sequence where we'd expect a '9' for a '69 carb.....

[Clem Z.]

Re: Mid 70s Quadrajet 7045213

7045213 is a 1975/76 350 ci HD truck CK 10/20/30 series non calif.

[Clem Z.]

Re: Mid 70s Quadrajet 7045213

7045213 is a 1975/76 350 ci HD truck CK 10/20/30 series non calif.

[james Kekeisen]

Mid 70s Quadrajet 7045213

As Clem points below and he did for me as before, it's a mid 70s truck carb, I'm really just "practicing" for when I get my hands on a decent 7029207. But Jack your clue was excellent and I should have looked more closely but the mounting holes for the choke cover are NOT tapped.

Carbuerator.com tech folks said it won't work well on a 69 any thoughts?

[james Kekeisen]

Mid 70s Quadrajet 7045213

As Clem points below and he did for me as before, it's a mid 70s truck carb, I'm really just "practicing" for when I get my hands on a decent 7029207. But Jack your clue was excellent and I should have looked more closely but the mounting holes for the choke cover are NOT tapped.

Carbuerator.com tech folks said it won't work well on a 69 any thoughts?

[Clem Z.]

Re: Mid 70s Quadrajet 7045213

the Q jets from HD trucks(no cat convertors) are good carbs for performance because they are not calabrated lean for the convertor. i use these carbs where the race tracks require Qjets on the engines.

[Clem Z.]

Re: Mid 70s Quadrajet 7045213

the Q jets from HD trucks(no cat convertors) are good carbs for performance because they are not calabrated lean for the convertor. i use these carbs where the race tracks require Qjets on the engines.