One more Q-Jet question please.

[James Keddie]

The original Q-Jet for my '70 350/300 MT engine is MIA, and I would like to look for a correct replacement. The TIM&JG lists 7040203 as the first design and 7040213 as the second design carb. My question is, can I determine from my build date if I need the first or second design for correct carb?
Thanks,
Jim 42765

[Joe L.]

Re: One more Q-Jet question please.

James-----

My guess would be that the change occurred about mid-May, 1970. However, the period from about April 1 through about July 1 would be the "no man's land" or "period of uncertainty". After about July 1, I feel pretty confident that the 7040213 would have been used. So, if your car was built in the January, 1970 through March 1970 period, I think we can safely say that it got the 7040203. If it was built in July, 1970, then I'd say it got the 7040213, for sure. For April through June, I don't know. However, April was likely the '203' and June was likely the '213'.

[James Keddie]

Thanks Joe! My build date is May 27th 1970,

so it looks like either carb would be period correct. Is one of these two carbs better than the other for driveability?
Thanks again, Jim

[Patrick H.]

Re: Thanks Joe! My build date is May 27th 1970,

Jim,

After 35 years of wear and tear followed by a rebuild, countless carb kits and/or a restoration, I don't think you'd ever notice a difference between one model and the next. I believe the condition of the carb will mean far more than its number.

Patrick

[James Keddie]

Re: Thanks Joe! My build date is May 27th 1970,

Thanks Patrick! I agree with your statement, but I seem to remember reading somewhere that the difference between these two carbs (first and second design) had something to do with the choke. Didn't know if the first disign was a problem and therefore they came out with the second design as a fix.
BTW, gotta complement you on your awsome yellow coupe!
STW, Jim

[Patrick H.]

Thanks! *NM*

[Mike M.]

Re: Thanks Joe! My build date is May 27th 1970,

The Rochester service bulletins for the two carbs indicate the only difference is the '203 was equipped with a dashpot to slow the return to idle rpm. The dashpot was eliminated on the '213. No other changes are indicated.
Mike