Thread: Quadrajet, and spark plug questions.

Tweet

Okay, this will be a 2 part post so please bear with me..

I have a 1980 Malibu with a worn out 229. I have purchased a 350 and 700R4 trans from a 1986 suburban.. The 350 has a computer controlled carb on it. I need to know if there is a way to make the carb work normally without the electrics. Secondly I need to aqquire an AC Delco spark plug heat range chart. My goal is to have a decent performer that gets good gas mileage too.. If my dad had a 454 in a suburban that got 14mpg in town. I don't see why 22mpg is out of the question.

Originally posted by pfogle
Okay, this will be a 2 part post so please bear with me..

I have a 1980 Malibu with a worn out 229. I have purchased a 350 and 700R4 trans from a 1986 suburban.. The 350 has a computer controlled carb on it. I need to know if there is a way to make the carb work normally without the electrics. Secondly I need to aqquire an AC Delco spark plug heat range chart. My goal is to have a decent performer that gets good gas mileage too.. If my dad had a 454 in a suburban that got 14mpg in town. I don't see why 22mpg is out of the question.

if you are not gonna use the electrics in the carb you need to get youself another carb. its a long ways from 14 to 22, plus a smaller motor pulling the same weight might use more gas. youll be better off if you get the computor and wiring harness to go with that motor. thats where the gas milage is.

Thank you. Let me clarify a little. The 350 is goin into the 1980 malibu. And he got 14 from a 454... So I would think that the 350 in the 'bu should get at least 20.... The current V6 with about 80hp gets 20....

Originally posted by pfogle
Thank you. Let me clarify a little. The 350 is goin into the 1980 malibu. And he got 14 from a 454... So I would think that the 350 in the 'bu should get at least 20.... The current V6 with about 80hp gets 20....

ok that will make the gas milage more obtainable, but that carb is not gonna get the job done. the computor motor should run cleaner and use less gas than a reg. carb. motor. i have done a lot of work on reg. QJ but not the computor ones, but there is a TPS senser in that carb that would have to work for it to be right. you would still be better off on mpg with the computor and wiring harness to go with that motor to get its max. i dont know, but i think a smog motor with no electrics is not the motor to be looking for gas miles. id wont the electrics. JMO

That's the odd thing. There is no TPS in the carb, just the mixture control...... That what confused me as well... I think I'll buy the edel carter knock-off and see what happens. I'd rather keep the q-jet as it's a great carb.... But if it won't work it won't work.

Originally posted by pfogle
That's the odd thing. There is no TPS in the carb, just the mixture control...... That what confused me as well... I think I'll buy the edel carter knock-off and see what happens. I'd rather keep the q-jet as it's a great carb.... But if it won't work it won't work.

has it got the big 3 wire plug l/ front of carb.?

Nope, just the little 2 wire one on the top, that is angled toward the front.

t1s10 is trying to say that there are a lot of variables contributing to mileage including rear gear ratio and the gear ratios in the 700R4 along with the shift points in terms of rpm and in the electronic version this has been supposedly optimized in the factory computer for a given set of gears and the torque curve of a given engine. Sometimes you can get lucky and everything transfers OK when the engine is changed but you need to compare the gears of what you have now to what you will have with the modified setup. On the other hand a four speed gives you more flexibility and the OD should give good mileage. In addition the low gear of the 700R4 is lower than many other transmissions so you should have low end torque multiplication as well as good mileage from the OD fourth gear. Then if you modify the 350 you need to select your cam and intake to make power in the range of your gears and shift points. Try

http://home.tampabay.rr.com/1bking/c...calculator.htm

to check out the rpm ranges of your gears. With the V6 your rear gear ratio may be pretty low for the 350 and the already low gear of the 700R4. You may not be off by much using the rear you have now because of the wide range of the four gears in the 700R4, but it might be a good idea to check AND use the electronic harness and computer chip the 350 was set up for. Hopefully the range of gears in the 700R4 may cover your new setup but the rear gear may be too low. Try running the calculations and try to get the electronic harness as lt1s10 suggested.

Don Shillady
Retired Scientist/teen rodder

Originally posted by pfogle
Nope, just the little 2 wire one on the top, that is angled toward the front.

you might be ok then. thats a whole new ball game

So that's just a try it and see what happens type thing?

Originally posted by Don Shillady
t1s10 is trying to say that there are a lot of variables contributing to mileage including rear gear ratio and the gear ratios in the 700R4 along with the shift points in terms of rpm and in the electronic version this has been supposedly optimized in the factory computer for a given set of gears and the torque curve of a given engine. Sometimes you can get lucky and everything transfers OK when the engine is changed but you need to compare the gears of what you have now to what you will have with the modified setup. On the other hand a four speed gives you more flexibility and the OD should give good mileage. In addition the low gear of the 700R4 is lower than many other transmissions so you should have low end torque multiplication as well as good mileage from the OD fourth gear. Then if you modify the 350 you need to select your cam and intake to make power in the range of your gears and shift points. Try

http://home.tampabay.rr.com/1bking/c...calculator.htm

to check out the rpm ranges of your gears. With the V6 your rear gear ratio may be pretty low for the 350 and the already low gear of the 700R4. You may not be off by much using the rear you have now because of the wide range of the four gears in the 700R4, but it might be a good idea to check AND use the electronic harness and computer chip the 350 was set up for. Hopefully the range of gears in the 700R4 may cover your new setup but the rear gear may be too low. Try running the calculations and try to get the electronic harness as lt1s10 suggested.

Don Shillady
Retired Scientist/teen rodder

Don,its coming out of a suburban and going into a car so its something he needs to look at, but i belive all of that would be a plus. im more concrened with the electrics of the carb. and EI. he dont want to hook up the computer up but, like you said to get the max. out of the set up he really needs the computor. you need to know what the gear ratios are and dont forget the small tires on the car.

The tires are getting changed. I think the rear gear is a 2.73, and the final in the trans is .70.. So I can just lock it in third for everything but highway travel... That's what I want...

Originally posted by pfogle
The tires are getting changed. I think the rear gear is a 2.73, and the final in the trans is .70.. So I can just lock it in third for everything but highway travel... That's what I want...

your gear is ok. go for it ,you can allways change the carb. if you have to.

OK, it might work out if you can recreate as much as possible of the electronics from the Suburban. I yield totally to guys like lt1s10 who have years of shop experience on various carbs and ignition systems. In my former career I often would take some electronics from a surplus instrument and use it for another purpose just by taping off the leads I did not use so if I had this problem I would try to make the hookups as much like the setup the 350 came from and then ask for help from folks on this Forum. One note of comfort is that when the 2003-2004 Corvettes went to high mpg setups they also used a similar rear ratio with a 700R4 and a 350 so you won't be far off mechanically. Maybe you could even use the shop manual for the Suburban with the parts it used. Also as lt1s10 said, the tires on the Corvettes and the Suburban were pretty large so it may be worth checking the effect of whatever tires you have, but if you are willing to just use the OD occasionally it might work out OK. You may also have to mess around with the electric switch for the OD and maybe install a manual toggle switch unless the harness from the Surburban takes care of that. My 700R4 was converted to a hydraulic switch but as I recall the stock 700R4 uses an electric switch for the fourth gear OD, but if you manually shift from third to fourth and then down shift to third manually you may be OK, but without that switch you cannot leave it in fourth and expect it to downshift automatically unless there is an electric signal to the trans. Good Luck!

Don Shillady
Retired Scientist/teen rodder

Actually, the 700 has a mechanical 4th gear (od) and then a torque converter lock up. My current setup is a 229V6 with a 200c three speed with a lockup TC. So it's just a matter of making sure I wire the TC correctly to the existing controls. The carb will either work or get replaced. I'm not going to mess with the electronics.. I had a '92 E150 that was MPFI on a 351w. While it got 17mpg empty at 70mph. It was a beast to work on. This is an old car with no provisions for a computer so it's not gettin one...