hey everyone, I am currently pulling out my old 305 and swapping in a 97 vortec 350 on a 91 k1500. I am keeping the tbi setup since I dont want to rewire the whole truck. I have 350 injectors, and I am getting a vortec to tbi intake. I am wondering if my computer will run it as is or will I have to get a 350 computer or would it be easier to get a chip burned for it? I would love to hear some input if anyone has done this kind of swap before, thanks

 

It will run ok with 305 prom in it I'd find a 350 computer of the same year model as your truck and put the 350 prom in it to maximize it for what it is. After that you gotta find someone to burn a prom but I wouldn't waste the money. It will run pretty good with the 350 prom the vortec heads and roller cam are a day and night difference over the TBI stuff which for the day was a day and night improvement over the 86 back carbed perimeter bolt heads and intake. The 305/350 computers are the same no difference there just the prom The difference in service numbers came from model year to model year changes. TBI will never be a max powerhouse but dang it it will be stone reliable for several hundred thousand miles and start every time and deliver reasonable power and gas mileage for what it is. Theres other options for more power just not outta TBI

 

All TBI v6 and v8 engines are roller cam.

Hit pcmforless.com and get a custom prom.
They are or was the leader in obd1 tuning.
There is also tuning software and a add on board to allow custom tunes by you.
Depending on the add on board you can pull the board, write the new tune and re install or get the real time tuning capability and beable to tune on the fly with no need to pull the board.

The software operate very similar to HP tuners,meaning it has 3d graps and tables.

 

No..... TBI 305's and 350's are flat tappet in the trucks...... passenger car applications were roller and the 4.3 regardless was roller. There are even 4 different 1 piece rear seal 350 block castings that aren't roller provisioned. They are 10045727, 14079287, 14088548, and 14101148.... no stand offs in the lifter valley and no cam plate provision. Roller 1 piece the trucks used prior to the 880 Vortec are 14011148, 14088526, and 14093638. Notice how one roller and non roller are so close in number.... my 92 came from the factory with the non roller 14101148 block so I couldn't convert it with factory parts if I wanted too.

Toilet bowl injection is getting pretty limited for the oem stuff as far as support. An adjustable pressure regulator and a properly burned chip for the 350 would help... but it will run okay on the stock 305's chip as well as a temporary thing.