Finally putting the 350 in place of the 305. Engine is paid for and being shipped. Its a stock rebuild and I am trying to figure out injector sizes. I really cant afford stock GM ones so I will go with accel probably. From what ive read, stock injector size on a 350 is 22#, but accel doesnt have that size. Only the 21# or 24#. So which is the best choice?

What are the consequences of going with the 24# vs the 21. I will be changing the prom for the correct engine size also.

 

The 21lb one will not kill you. its not like you are going to run boost or anything. Or are you? if you run bigger injectors than you need you may run into rich problems. Correct me if I am wrong.

 

not running boost or anything. Running too rich was my worry.

 

I personally do not see a problem with 21lb injectors

 

You will need to run lower pressure with 24's than you would with 21's. You should go with the smallest injector that will supply your engine. The disadvantage of larger injectors is you don't get as much misting with the lower pressure. So, as long as the pressure can be raised to supply the engine at max demand, the smaller injectors are desired - except that higher pressures reduce injector life.

21's will probably be fine with a stock rebuild.

 

great...thanks alot for the info! Any suggestions on fuel pressure settings with 21# injectors for my application? TPIS suggests 49-52 psi

 

then try it at 49 and see how that works out then work your way up. ah.. beauty of tuning!

 

I have a friend who put 19 lb injectors in his highly modified ZZ3 TPI car in order to get through emissions testing (he had been running 24#). He didn't get them changed back before the next race day, so he turned the pressure up a little to compensate. He ran quicker all night than he had with the 24#'rs.

Of course, this was in our rarified 5800' elevation air. But the point is, bigger is not always better. He's since moved to Ft. Worth, but health problems have kept him from seeing what the car will do down there.

 

I think i probably will just get the reman'd stock 22# injectors. I keep hearing not so great things about accel injectors. Dont know if its just a rumor in the industry or if people really have problems with them.

Spoke with tpis tech today and they suggested Ford injectors for quality but I've been reading about fitment issues and having to modify the fuel rail.

5800 ft? Where are you from? I used to live in fort worth. They dont liw when they call it "cow town". No....its a great place to live. Too bad he cant drive his f-bod down there

 

Denver area.

 

I used Ford Racing Injectors, bought from Summit, fit perfect, no problems in 1 year of driving. Less $$ than GM replacements and people seem to report they are more reliable then the stock size Accel injectors.