Hi, I bought my car and the guy said that he converted the car to a 350, the injectors and chip are both from the original 305. I would like to convert them to the 350. I talked to TPIS and they said that the 305 chip is the same as a 350 chip, they just said to get a fuel pressure regulator and thats it. Does that seem right? I would think that spark and timing would be different? Anyone know more about this?

Thanks

 

Yeah, that sounds like something TPIS would say.

The 305 and 350 Memcals are different, and there are PLENTY of differences even among various 350 and 305 Memcals for the same vehicles. I know of at least 4 different calibrations for the L98 350s alone - ALL automatics too.

Best thing to do is get the equipment and burn your own. Then you either just use an "Automatic" calibration as a base if your car is an "auto", or "Manual" calibration as a base if your car is a standard.

 

Also look to see if the spark module has been changed as well as the knock sensor. They are different for the 305 and 350. When I intially changed my car over to a 350 a "certain" company failed to tell me about the spark module being different. Thanks to many people on this board and reading current and past posts all's going in the right direction now.

 

What is different about the spark module?

 

It's tuned for a different frequency.
The acoustic signature varies as the bore of the cylinder changes.

You can play mix and match with sensors and modules, but it gets to be real time consuming for min gain.

 

Tuned for different frequencies?? How come a 350 ci. knock sensor works OK in a 400 ci.?
J

 

But does it work well? The problem is, there really is no alternative for the 400 since GM never made a 400 with a KS. You are just "making do with what's availabe", not "what's right".