This weekend i installed the last part of my 350 swap, the 350 injectors and 350 chip, turns out the chip i pulled was bad so now im stuck back with my old 305 chip. The 350 injectors are still on there and today i was calling around trying to get info on a custom chip. I was told today (this is the first tiem i heard anything like this) that my 305 chip was sufficent as along as i had the 350 injectors. Now i read the sticky and it said that the engine can run on a 305 chip but its better if its changed.

I have a 350 engine almost exactly like that in a 350 Caprice, and the guy told me that unless i was going to put a cam in it(which would than require a custom chip) that in woudlnt need a chip and the only thing that i would need to make the engine run any better would be an Adjustable regulator for fuel pressure. Is this true? Im getting two conflicting opinions here and id like some input and clarity.

Right now the car is running better tha before, even with the 305 chip, it feels like it has some more power, which he says is because of the injector swap, he also said that the pulses from the injectors is not much different, which almost erases the need for a custom chip.

Thanks for any help

 

65 lbs inj vs 55 lbs is 18% larger flow.

350 vs 305 CID is 14% larger engine. So you are over fueled unless you compensate with fuel pressure. You could have increased fuel pressure and kept the smaller injectors. Running at less than 12-13 lbs FP may not be the best alternative.

 

I just saw your other post too, in which you're getting a code 51. You can't use a chip from a truck, it's a different ECM. You need a chip from a 1228746 ECM. A Caprice 350 car with that ECM would work, maybe not any better than your current 305 chip though.

You need to read the stickies about tuning the prom. You will need a custom chip, that guy was wrong, you could maybe compensate for the time being but it will never run like it Could unless you tune the computer yourself or have someone tune it in person that knows what they're doing

 

So i figured, It runs stronger now, i already have an adjustable regulator and a new fuel pump to put in. And i know i cant use the Chips from a truck, thats something i learned afterwards, i mis read a thread on what i could and couldnt use, Even the caprice chip did not work which i know is from a 350 TBI caprice, and everything i have read said that i could use that chip. Also i had my buddy who works at the dealership look up caprice chips for me, i gave him the code on the chip and he says the chip for a 350 and a 305 tbi caprice is the same in GM parts computer he looked at so idk about that one.

Everything has led me to believe that i would need a chip so when i talked to this guy, and he told me a bump in pressure would more than compensate, i was quite confused, I will be getting a chip sometime in the near future, hopefully before summers end, but now that i have 350 injectors on there, and am running a stock 305 chip, what should i do about my fuel delivery? I have a 350 regulator on there now, because i just swapped the whole pod onto my stock tbi base so would that be getting fuel through at the right PSI to compensate for the bigger injectors and my 350 engine even though my computer thinks i have a 305 still?

 

you could change the spring in the regulator with a stiffer one or just buy an adjustable fuel regulator.