70 QJet Carb

[Lee McGlamery]

Hi - I have a 70 350/350 in need of a new/rebuilt carb but I am confused on what was originally on the car. The GM parts manual shows a 7046905 as the GM part number for a 350 with the high performance engine and a 17051998 for the 350 (except high performance). Some of the Corvette Parts suppliers list one remanufactured QJet for the 300 HP and another for the 350 HP which is in line with the GM Parts Manual. Others, including the Doc, show the same QJet for both the 300 and 350 HP engine. I recently purchased a remanufactured carb in hopes of curing a problem with a very rich running condition including fuel laying inside the intake manifold. I know that this is normally a problem with the floats being fuel soaked but the junk rebuilt carb must of had the same problem as the carb that I origianally took of the car.

Bottom line - was there in fact a different QJet for the 70 300 HP and the 70 350 HP? Also please advise of the diffence of the two carbs if in fact there are or were two different carbs on the 300 HP and 350 HP. I also have ordered every different choke lever advertised to go between the spring thermostat on the intake and the carb choke arm and none fit. I had the same problem with the previous carb I took off the car.

I violated the Patrick Golden Rule and did not keep the first carb that I took off the car.

Thanks

Lee

Thanks

Lee

[Patrick H.]

Re: 70 QJet Carb

You dummy! You realize I had to say that. Rule #2 is not to mess with anything on the car in the first year you own it.

Anyway, in 1970 there were a plethora of carbs, depending on motor, transmission, or ECS (emissions for ACalifornia) equipped.

300/4spd: 7040203 (early) or 7041213 (late; must be very late as it's a 71 number)
300/auto: 7040202 or 0212
300/4sp/ECS: 7040503 or 0513
300/auto/ECS: 7040502
350/4: 7040207
350/4/ECS: 7040507

Note that for 1970, these carb numbers were shared with MANY other Chevrolet cars. As a result, good cores and correct dates are easier to find (and cheaper to buy) than surrounding years. I think your book is also showing replacement carbs from later years, not 1970 numbers.

Patrick

[Geno B.]

Re: 70 QJet Carb

i think i have the original carb 7046905 you mentioned in my garage. i you want i'll go dig around and see if i can find it.

[Clem Z.]

Re: 70 QJet Carb

my GM carb manual shows the only carbs for a 70 350/350 corvette, 7040207 and 7040507 for calif. the pri jet is #76,pri rod #44 and sec rod BA with a .057 dia. tip

[Joe L.]

Re: 70 QJet Carb

Lee-----

There were originally all of the carbs which Patrick identified used for various 1970 Corvette applications. In later SERVICE, these were all "whittled down" to just the 2 part numbers which you mentioned. Even these were discontinued quite a few years ago.

In the rebuilt carburetor line, rebuilders may have further "whittled down" the available part numbers to just 1. This carburetor will SERVICE all of the applications but it won't be exactly right for any of them. The differences in the original carbs, except for California with EEC carbs, was relatively minor and using just 1 carburetor for all apps will satisfy most folks. The rebuilt carbs may carry a carburetor part number which is nothing like the original numbers, though. Rebuilders are more concerned about FUNCTIONALITY than "numbers". Many carb bodies may be usable for building into a serviceable 1970 carburetor app.

[Clem Z.]

Re: 70 QJet Carb

the only differencr i can find in the parts for these different carbs is that 7040207 and 507 have different part number air horns,floatbowls and throttle body assy,the metering looks all the same. all the rest use the same parts.