sorry for my noobness. trying to put together a speed density setup. i have an ecm and everything necessary to custom program a prom, except a factory memcal. wondering if i could get the 305 prom since its cheaper and then just tweek the new chip on the moates adaptor to use the 350 i've been building.

I believe you need a 350 memcal for a 350 cid engine. I ran without one and unchecked the malf flag and I also ran with a V6 memcal. limp mode did not work. 305 memcal may be close enought to run engine but 350 is preferred. I suspect engine will run very rich.

I'm lucky to have stumbled upon this - I swapped out my 305 for a 350 6 years ago I had to use my old 19 lb injectors and the 305 prom code or my oil pan would eventually fill with gasoline - the car always ran rich and stopped passing smog - it's sat in the driveway for the past 4 years I had a 4th gen WS6 as my DD at the time. 3 years ago I found out I had a terminal illness and it seemed I was going to die. That's a long story in itself, but I seem to be beating the odds and recovering. I had to sell my 4th gen during my down time as I couldn't afford it. My parents let me keep my 3rd gen in their driveway during all of this. I have not been able to drive or work for a two years now, but hopefully that will change soon(ish). I miss my camaro to death and I want to fix her.

I'll get to my question now (sorry for the text wall).

I always used the 305 memcal and my bmi's were all over the place no matter how much I tweaked the tables. Could this be because I am not using a 350 memcal? Also I have a manual so would the 350 memcal need any tweaking other than changing that in the prom? TIA to anyone that can help me here.

from what i can tell the 350 prom is the way to go. not positive since i've only just scratched the surface of prom tweaking, but if ur using the 19 lbs injectors have to change the programming on the 350 to use the 19 instead of the 24 lbs. also the 19's might not be able to get enough fuel to the 350 which could be causing the crazy bmi's. once again not positive since i'm still pretty new to all this. good job beating the odds btw!

yeah It's been a few years since I've been doing this, had no problems with my 2 305 engines - after the last swap the thing miss fires like crazy at low rpms - I purchased some new 32 lb injectors, but like I said the oil pan would fill with gasoline if I told the prom the engine was a 350 - I've checked the fuel pressure and it's just slightly above normal but just slightly - I don't think the vacuum was off when i was trouble shooting year ago - my other theory was I still have the 3.08s in the rear and maybe that isn't playing with the crane cam too well, I think I may swap back in the stock 350 cam and see how it does with that- I still don't think my oil pan should be filling with gas though... - thanks for the well wishes -

the differance between the 2 when used with a diy chip, or whatever kinda of tuning you choise to use. is the knock sensor board should match the size your running. as in 350 motor, 350 knock sensor and memcal. to be 100% right


i will say i've read about people using anything from v6 to the wrong size v8's with no real issues. i have run a 305 chip on a 350 for years, with no issues. and in another car i'm running a 305 chip in a 406 and while i understand the knock sensor isn't turned for this bore size, it still seems to work. it pulls timing if it hits a lean spot or a spot with to much timing in.

i don't know whatyear tpi your running, but if its a map setup using $8D. i used my 305 bin to run my 406 by just upping the injector size to match what i put in, being 24# and the size of the motor. it was close enough to start and drive ok. i worked on the ve tables from there. i never could nail down the iat table for this motor, so the blms drifted around as the air temp changed but it wasn't anything the blm's couldn't cover for. it just bugged me, so i ended up running the boost code59 even thou its an n/a car. its just more enjoyable code to tune to me. but anyways, you may have had an o2 sensor issue. do you have headers and the old school 1 wire o2? those dont always seem to work well together.