I originally had a 305 TPI with the M5 (so I believe it had same ECM as 350) and I am putting in a fresh rebuilt 355 with 10:1 CR and Lunati 60101LK cam. I realize that to Perfectly dial it in I would absolutely need to burn a new chip, but I'm hoping that it will still run 'good.' So what I want to know is what can I expect, what are your opinions? Should my stock computer be able to handle it? This cam is supposed to be computer compatible but still, I want expert input.

Perhaps unlike some people's goals, I want big TQ numbers and have less concern about HP. The motor is already built and likely in the process of being dropped in at the shop. I bought a set of used 22# injectors, had my 58cc heads redone, port-matched intake to heads, and I need to get a set of shorties. Also trying to get rid of my EGR system, but that's another story.......

 

No. Running non stock injectors is already setting you up for an AFR disaster. You will have no clue what the computer is doing with a setup that far from stock. This is the time to invest in DIY chip burning....sorry. A stock chip will be sketchy at best, driveability wise. If you're asking, you already know the answer. It's going to need to be tuned.

 

Whoa hold on a sec, I'm pretty sure (please correct me if I'm wrong) that, like I said in my OP, the ECM for the TPI 350 is the same as the 305 with the M5. And if that's the case, the 350's came with 22# injectors stock so why would that be an issue? That being said, I really think you're 100% right about the DIY programming, I would love to get my hands on the equipment and learn about it. How much does that cost and what exactly would I need?
I never really considered that my motor was that far from stock (With exception to the cam of course), do you really think it is? Also the computer doesn't measure CR, it just detects if it's detonating early right? (Again, I need to be corrected if I'm wrong) Speaking of which, aren't the 305 knock sensors different from the 350's? Thanks for your response.

 

Um, the ECM can have different proms. Just because the bare bones ECUis the same part #, '165 or whatever, does not mean the tunes are at all the same between different motors, years, options, etc. A 305 and 350 prom are calibrated for different injectors. A 305 w/ larger than 19 lb hr injectors will run extremely fat and waste a lot of gas, and hp.

Use the search function! Lots of people have tried fudging stuff like this. I could not in good conscience, recommend it, or say you will be okay. I would sooner recommend going carbed (and I hate carbs) if you are not willing to tune.