I'm rebuilding my 750 qjet and yes I know i should spend the 200 and send it off to get rebuilt and tuned. but so lil money and its not what i want to do with the engine anyway right now. (id like to build the 350 up a little but untill the $$ its stock.) It's going on a stock standard compression 2bbl engine and i'm looking to put a cheapie (factory) intake mainfold on it. can anyone give me an idea on if I should rejet it on my own. I'm also not planing on recurving the distributor unless someone has some pointers along that route and if its not too terribly difficult or expensive. the rods in it now are 44b (or 3) for primary and BS for the secondary I'm not sure what the jet is (didnt clean it enough) it is a factory 70 4bbl buick carb also. it has the standard flow needle and seat. Nate
Nate, Try using the rods and jets it has now. There's no harm in trying, but if you decide to swap primary rods later, you'll have to rip it apart again. I used the factory rods and jets on my 800 cfm qjet for my 350 and it seems to do an ok job...It's probably not the best I could do, but it's running. If you're not doing anything else to the engine, stock rods and jets should do fine....especially if it's for a 70 350 motor already. just my 2 cents.
Nate, According to my 70 Chassis manual, there were 2 Q-jets on 350's. The 7040244 and the 7040245. It sounds to me like you have the 7040245. That is the Q-jet for a 1970 350 with manual trans. Stock jetting is .073 jets with 43B rods. Secondary rods are BS. They have a .0947 power tip. That is a lean rod. I would leave primary jetting just the way it is and use a richer secondary rod. Try an AU rod (part#7033655 .0527 tip) The secondary rods are easy to change. I would do that. I think your primary jetting is already performance oriented. The 7040244 (auto trans) has .069 jets and 45B rods with the same BS secondary rods. Hope that helps.
intresting intresting. it is a 7040244 carb acording to the stamping with the aformentioned parts. has the 43B rods and the BS secondary. and i am putting it on a car with an automatic trans. may have been rebuilt once before? although i'll have to check the jetting still. next time i have it apart i'll verify that it was a 43B rod (though im 95% sure it said 43B) but its the same story none the less. thanks for the tip. any tip on getting the secondarys to line up when you drop them back in i can't get them to line up and drop in right. Nate
Yep, make sure they go in hooked up to the hanger the same way you removed them. Do not force them as if they get bent you can start looking for another set. I can't tell you if the hooks should go from the inside out or the outside in (without going out to my car - and I'm at work at the moment - shhhh) but I suppose you have a fifty/fifty chance of getting it right. If not then try the other way.
I don't put the secondary hanger and rods on until last. It's a simple one screw operation. Do the secondaries last and concentrate on getting the four other transfer tubes into their correct holes. Warren
yep yep yea.. i'm doing that.. im assembling nearly all of it then putting the secondarys in last. they just like to spread apart and miss the holes. I musta spent about an hr trying to get them to drop in and still no luck and normally im good at that kinda thing too.. i'll try again when it comes to assemble it finally heck the primaries were a cake walk in compairason. Nate
E-mail me if I can help. I've rebuilt Q-jets for twenty years as a side line to help pay for my racing. Warren reno1@continet.com Tweaked a '73 GS455 to run 13.95, stock with 130K miles on it.
