Wrong Carb on 69 L36

[Michael C.]

Many years ago I replaced the carb due to leaks caused by corrosion because the car sat up a long time. I don't know where I purchased the replacement, but now I see that I have a 7029207 instead of a 7029215 (as specified in the service manual). It's been a long time since I drove the car, but as best I recall is that the performance wasn't what you'd expect from a 390hp. According to the service manual the specs on the two carbs are the same except as noted below:

	7029215	7029207
float level	1/4	3/16
main metering jet	.071	.066

It appears that Q Jets are rare and expensive (new or rebuilt). Should I expect the performance difference to be worth pursuing the right carb? If yes, suggestions for possible sources would be appreciated (new or rebuilt).
Thanks
Mike

[Rocco S.]

Re: Wrong Carb on 69 L36

Mike,

There's more than just float level and jet size that determines performance of a Q-Jet. There are are many variables like primary and secondary metering rod size, power valve spring rate, accelerator pump adjustment, secondary metering rod hanger and secondary air valve spring tension. Not to mention Choke and vacuum brake settings.

Almost any vintage Q-Jet can be built and set-up to run well. But you need to determine what parts you have as many of these carbs have been through rebuilders and use "universal" parts that may not work with your exact combination. Any engine modifications will require the stock carb to be recalibrated.

If you do find the correct carb I can send you the factory correct parts list as I have a master Rochester Carb binder covering all Rochester carbs from 1966 thru 1977. Just send me a PM and carb number.

If you want to learn more about Q-Jet carbs, look for a book written by Doug Roe. I'm not sure if its still in print but should be easy to find used.

Rocco

[Michael C.]

Re: Wrong Carb on 69 L36

Thanks for the reply Rocco. I'll be in touch if I decide to replace the carb. Right now I'm trying to determine if it's worth the expense.

[Mark E.]

Re: Wrong Carb on 69 L36

I acquired three "correct" Q-jets over the years for my '70 454. I found them on e-bay (separate purchases, different times) and paid hundreds of $ each, then paid hundreds more to have each restored. Today they sell for thousands. Probably the highest appreciating asset I've owned. I call it the Joe Lucia investing strategy.