Reduced size TBI injector

[trades707]

I have three, two barrel GM TBI inector bodies to mount on a three, two barrel manifold for a 1948 Lincoln 292 ci V-12. Of course the injectors are sized for two to run a 300-350 ci engine, so my individual injectors are about three times too big. How to downsize? Would a Geo Metro injector fit?
Thanks
Abe

[joegreen]

I dont know the answer but that lincoln v12 sounds awesome.

[tayto]

4.3l or 2.8l injectors

[1project2many]

GM TBI injectors come in different flavors.

TBI:
http://www.jegs.com/images/photos/700/735/735-HP645-800-2.jpg

Late model Multec BF:
http://www.witchhunter.com/images/GM%20TBI700c.jpg

All injectors in the same family are physically interchangeable. Smaller engines need less flow so you'll need to find a similar injector from a smaller engine. Sometimes you can find a "pod" to use the smaller BF injectors (used on newer TBI's) on the older throttle bodies. Holley sells these for $71 each but they were also used on OEM Throttle Bodies in medium duty trucks.

https://rspimages.holley.com/534-162.jpg

Injector size should be selected for the expected power level, not the engine displacement. I saw a 400 cubic inch engine last weekend that was rated at 45 hp. Although the displacement matches some of the larger GM automotive engines, that engine running EFI would an injector that delivers little fuel.

The throttle body size should also be chosen based on airflow, also related to expected power output. It might turn out that you are better of selling those larger TB's for smaller two barrel units or even single bore TB's. The unit on the left in this image is from a 2.8L V6:
http://carphotos.cardomain.com/ride_images/1/2960/2601/7398800021_large.jpg

And this single bore unit is used on 1.8 to 2.5L GM engines:
http://thumbs1.ebaystatic.com/d/l225/m/mjyJCt_fVIi9IEGRrsz3Z4Q.jpg


Ultimately, the list at the bottom of this thread should help you find applications with smaller injectors.

http://www.gearhead-efi.com/Fuel-Injection/showthread.php?857-Some-Injector-Info

[trades707]

Thanks guys. Looks like its a trip back to the pick-a-part for 2.8L throttle bodies. What is the most likely vehicle to find them on?
Abe

[1project2many]

S10 pickups and Blazers from mid to late '80s are the most likely sources.

[1971karmannghia]

1.8/2.0/2.2 4-cylinder GM TBI setups MAY have the injectors you seek?
2.8 / 3.1 TBI units on Isuzu Trooper/Rodeo