4.3 TBI to 350 TBI swap

[FrankieD61]

Also, the donor 350 TBI I have is a GM Goodwrench motor. Will this cause any problems?

 

[PlayingWithTBI]

Is tuning hard? I've never done it.

Go on his website and go to "Information" tab/Introduction to tuning parts 1 & 2.

Also, is finding computers and proms for these trucks hard? Because, if I do find one that is for a 5.7 but automatic trans, should I buy it and just deal with the SES light?

I don't know about your area but, if you do find one, I wouldn't get one for an automatic. When the SES light is on all the time, you won't know when something is really wrong. You'll just think it's the trans again.

 

[PlayingWithTBI]

Also, the donor 350 TBI I have is a GM Goodwrench motor. Will this cause any problems?

No, mine was one too.

 

[HotWheelsBurban]

Only problem we had with a GM Goodwrench replacement engine (our 79 Burb had a 350 one in it when we got it in '89) was the starter ear on the block breaking off. That had happened before we got it, and someone had welded a stud and ear to locate the starter. But we put a couple hundred thousand miles on it and it didn't use any oil, so it was a pretty good engine.

 

[FrankieD61]

Thank you, guys. My buddy that I'm doing it with seems to think that my existing computer will work; he is VERY SURE that it will. I guess we shall see. I will repost to this thread of I have any tuning questions ( I probably will). If it doesn't work I'm going to probably use the flash 2 system (send out my existing computer, have them put their chip in, and I'll do the programming and HOPEFULLY get it running. As I said I may need some help with this. As long as you guys are willing ).

 

[FrankieD61]

Is there any other tips or tricks that I should know of before I jump into this?

 

[TagAllen]

I do not believe the computer donor would need to have the same rear axle gear. Your VSSB should take care of that.

Did they mention you will need to change the chassis side motor mounts?

 

[FrankieD61]

I do not believe the computer donor would need to have the same rear axle gear. Your VSSB should take care of that.

Did they mention you will need to change the chassis side motor mounts?

Yes, I grabbed the motor mounts from a diner truck with a 350. What about the throttle body, can I use the one from the 4.3?

 

[Schurkey]

Yes, I grabbed the motor mounts from a diner truck with a 350. What about the throttle body, can I use the one from the 4.3?

At minimum, you'll need to install the 5.7L injectors. I think the air passages are the same size, but not absolutely certain.

 

[TagAllen]

At minimum, you'll need to install the 5.7L injectors. I think the air passages are the same size, but not absolutely certain.

I dont know if the 4.3 uses the same fuel pressure spring either.


I dont know exactly what you mean by a diner truck but if its not a GMT 400 they may not set the proper location forwards and back to let the tranny line up correctly. Also new mounts from Rock Auto are under $10.