I've done a search and I'm not finding enough info on 90-92 SD 305TPI to 350 SD TPI swap. I have a 91 GTA 305 TPI A/T and a 350 TPI A/T out of a 91Z28. Things I know that need to be changed, knock sensor, injectors, prom and EGR. Is the ESM different from a 90-92 SD TPI 305 and a 90-92 SD TPI 350? Anything else I'm missing? I was reading about 305 heads on a 350 and someone said you needed to change the ESM. Thx. in advance for any help, Rob

 

the esc module is defferent as well, other than that i think you have everything

 

Thx. for the info.

 

I've done some more research and its looking like the 90-92 Speed density TPIs are the same. I believe that the ESM or ESC is control by the prom on 90-92. 89 and older seem to be controlled by the ESM or ESC and have different P/N for the 305 and 350s 89 and older. I'm not finding different P/N for the 90-92 305 and 350s.

 

Ok, just got of the phone with 2 parts stores. 90-92 TPI 305 and 350 have the EXACT same ESC P/Ns. 89 and older TPIs have different P/N for the 305 and 350 ESC.

 

Hey Dokken how ya been. Finally think I've found my 350, a 94 TBI truck motor. Im gonna seitch over my TPI unit. Hows the GTA comin?

 

Hello Bryan, well shortly after you bought the fender from me my wife passed away and it threw me for a huge loop. The GTA came to a scretching stop until about a month ago. I've collected new drop springs, struts, shocks, disc rearend, 3:42 gears, 3" exhaust, most of the black interior, 140 speedo, 17x8 Torq thrust II wheels with General Exclaim 245/45 tires, J&M LCA's, LCA relocation brackets, panhard and caster camber plates, UMI torque arm, complete Felpro gasket set, aluminum water pump and freshly rebuilt 700r4 with vette servo. I need 1 more 22# injector to match the 7 I have, need the prom reprogrammed and going with a RV cam&lifters. I picked up a 350 4 bolt 1 piece RM seal just bored .030 over that I will build slowly but radical. Right know I'm sticking with the 91 stock 60K 350 with some little upgrades and putting the money into the suspension, tires&wheels, converting beechwood to black leather interior and new paint. How did your paint job turn out? Rob

 

Damn sorry to hear about your wife Rob. As for my paint, after I picked up the fender, I also picked up a spare power bulge hood to swap back and forth between. Had the GTA on a trailer headed for WV for paint, made it to Greenville SC and my uncle (the painter) called and was in the hospital. So I headed back and still haven't made the journey back. So shes still not painted. Maybe we can get together sometime. I'm thinking that is I get this 350, I'll do the same as you, build slowly. Thinking of going to a 383 but will stay with the GM TPI setup. Thinking also of going to true duals. Still looking for some cheap headers to throw on the 305 right now

 

2 days after my wifes passing my 91 Z28 parts car was delievered. Just yesterday I unloaded the SLP headers that were on it that would have been perfect for your car. I take it the truck engine is a 4 bolt main? I still have that 92 350 TPI engine that needs to be rebuilt.

 

Still have the TPI unit on it? Got the 350 ECM for it?
The trucks a 4 bolt

 

No TPI unit. Just the long block. I have a 730 but it won't work with your 89 setup. Are you sure the truck engine is a 4 bolt? It is a myth that all trucks have 4 bolts.

 

I had the guy pull the block codes and I checked them.

 

The codes are not always right. I had a 89 silverado and the codes said it was a 4 bolt, pulled the pan and it was a 2 bolt. GM crate engine also said 4 bolt pulled pan 2 bolt. You have a 50-50 shot with some of those GM block codes. If the engine came from a 2500, 3500 etc. you have a better chance of it being a 4 bolt. Very rare to find a 4 bolt in a 1500.

 

Its not that expensive to buy the 4 bolt caps and have the block machine for them.

 

I'll probably just go with whatever it is, if its a 2 then oh well. Just gonna build it up a little, not a monster. Im trading an older riding mower for it, so I can't complain too much. It supposedly runs great? But Im gonna go thru it anyway.

 

I wasn't trying to talk you into buying my engine, I wanted to make sure you don't get disappointed when you pull the pan. Lawnmower for the engine sounds like a good deal.

 

I've never heard that 305 and 350 EGR valves are different.

 

Well the a$$hole sold my motor this weekend. Guess I'll wait
Don't know bout the EGR's

 

If you look in the 82-92 parts and illustration catalog the show different P/N for the 305 and the 350. I have a number of 305 and 350's and they also have different P/N's on them as well.

 

I've got a 350 in the basement with your name all over it!! Come an get it!!

 

How much did you want for it? I'll have to speak with the Mrs. She did care bout me trading the mower. Is it the one that frozen?

 

badbandit66 check your PMs

 

I called the link that I posted above and was told to be dead on I would need the a 15 teeth shaft gear and a 41 VSS gear due to my tires being 25.25"-25.5" tall. If my tires were 26 the 17 teeth and 45 teeth would have worked. BTW, GM only carries a 44 teeth gear and less. They also said use the calculator to figure out what you need exactly. Just click on the spinning odometer. Sorry I posted this on the wrong board, my bad.

 

rob This is Brandon in Atlanta email me ponusa@yahoo.com