Question about tbi computer on 305-350 swap

[Nw2000]

Hey I’m new to these forums so forgive me if this is in the wrong section. I have a 1995 gmc c1500 and am currently in the process of swapping the 305 for a 350. The 350 engine is up and running thank goodness however I have a question about the chip. I had done some reading saying that for optimal performance you need to swap the current 305 chip for a 350 one so I got a jet stage 1 chip and it seemed to not run as rich once I swapped it out. I’ve seen where the jet chip has prongs that connect to the factory prom chip and was wondering if that was necessary and if so will the factory 305 chip conflict with the new 350 chip? This is the first time I’ve ever done anything like this so any constructive advice is appreciated thanks.

 

[David89gmc]

Question: doesn't the Jet EPROM replace the factory EPROM? My background is embedded systems but I've never upgraded an automotive chip. The typical way chips are upgraded is by replacing an existing chip with a new one. The old is removed and the new is plugged in.

 

[Nw2000]

Question: doesn't the Jet EPROM replace the factory EPROM? My background is embedded systems but I've never upgraded an automotive chip. The typical way chips are upgraded is by replacing an existing chip with a new one. The old is removed and the new is plugged in.

I think you’re right thanks for the input.

 

[L31MaxExpress]

Question: doesn't the Jet EPROM replace the factory EPROM? My background is embedded systems but I've never upgraded an automotive chip. The typical way chips are upgraded is by replacing an existing chip with a new one. The old is removed and the new is plugged in.

On Memcal based systems the chip is usually supplied on a piggy back adapter and the original memcal plugs into the adapter and the adapter into the PCM. The limp home mode and knock filters are engine specific to the original memcal. Get one from a 350 Van, Truck or SUV the same year and trans type.

 

[Nw2000]

On Memcal based systems the chip is usually supplied on a piggy back adapter and the original memcal plugs into the adapter and the adapter into the PCM. The limp home mode and knock filters are engine specific to the original memcal. Get one from a 350 Van, Truck or SUV the same year and trans type.

Alright I looked one up on eBay I’m gonna go ahead and get one that is compatible with the drivetrain and ecm from the same year thank you.

 

[PlayingWithTBI]

On Memcal based systems the chip is usually supplied on a piggy back adapter and the original memcal plugs into the adapter and the adapter into the PCM.

I don't have any experience with those newer PCM, ha ha. Can't you just swap out the OE chip and drop in a 27SF512 flash chip on those 7427 PCMs?

 

[L31MaxExpress]

I don't have any experience with those newer PCM, ha ha. Can't you just swap out the OE chip and drop in a 27SF512 flash chip on those 7427 PCMs?

You could swap out the chip on the Memcal but it is easier to get the piggy back adapter from moates. Still does not fix the limp home or knock filtering. The newer PCMs do not have an ESC module and the Memcal does its function.