i swaped my old worn out 305 and rebuilt a 350 and now as i was trying to break in the cam it was randomly reving up then it would go back down to were i was holding it, also felt like it had a small miss, and it seemed to be burning way to much fuel. the only thing that i changed was the injectors, i read on here that the 350s need a 22 lb/hr and before finding what size i needed i bought 28 lb/hr. so i dont know if i would be better off putting the stock 19 lb/hr injectors back in or if i have something else wrong. any help would be appreciated

 

You would be better off throwing the 19's back in. The ECM's can only cover around a 10% differential in injector size.
If you can reprogram your prom you can use the 28's.

 

what year is the car? massair or speed density?

 

its a 1989 with mass air flow, then also if i were to put the 19 lb/hr injectors back in it it would lean out would it, the 350 has a little more power then stock

 

When you say a little more than stock what do you mean? Can you list cam specs or is it stock, what is your compression stuff like that. It is definately a good idea to get the chip burned to your engine specs. Otherwise you will get a lean miss and surging. I am in the process of a 305 to 355 (more than stock swap). I can recommend an excellent person to burn you a chip that will be dead on! And very reasonable.

 

well its bored 30 over and it has 9.3:1 compression, 278 intake and 288 on the exhaust for the cam, and ya if i get a hold of some one to do that with my prom would be great thanks

 

so now i have one more problem, i put the stock injectors back in and put everything back togather and now it wont idle, it starts right up and runs but once you let off the gas its like it shuts off, i think that it might only be that the timing is off but we have no way of timing it when it doesnt idle. any help would be great thanks

 

u gotta do the chip for it. wont idle most likely the throttle blades arent open enough and iac is maxed out. I am doing the chip and a intake for 90-vert now. I can do yours if you want. u pmed me and i never heard back. u can then use the larger injectors in it too. I would need all the specs on the engine . just pm me again. keep at it like this and u will tear up the ring seal in that motor. if it is a flat tappet cam will wipe a lobe off it too. be very careful with a new engine. tune has got to be spot on to make it break in correctly so it lives and runs as strong as it should.

 

You have a separate problem. 19lb injectors will work fine down low where you need it without any damage to your engine. Go over all of your electrical and vacuum connections to make sure you didn't miss one.

 

yes and no with what was just posted. Yes you do have some other problem causing it to not idle and no the 19 LBS WONT be good for it. If you have a larger than stock cam that doenst make the same vacuum as stock then the kpa will change in the program which in turn makes it idle way richer normally. In a massair car it normaly tries to correct that and goes too lean or back and forth. depending on the size of the cam and not advertised that tells me nothing compared to the numbers at .050 on the cam specs. from there I can tell u what it might idle around kpa and how much vacuum the engine will make. if the blm is too far off it will not idle. all that can be fixed with a new program being done to it. sounds like the iac isnt working right and tb is shut too much. especially if u can give it a little gas and it idles. or u have a lair leak after the mass air. make sure your boot th the throttle body is tight.