GMC / Chevy TBI 350 -> TBI 454

[Corban_White]

So, I have a 91 gmc with a very tired tbi 350. I had planned to build a 383 but with the use this truck sees I have decided that I can get more bang for my buck by just swapping in a BB. What parts do I need to get aside from the motor and the injectors/throttle body? Will my accessories bolt up? Will I need different brackets for the accessories?

Also, what is the recipe for a CHEAP torque build? I know it can get pretty wild but since I am probably going to have to put rings and bearings in any engine I get are there some less expensive things I can do to boost the torque? I know there are quite a few guys on here with a vast amount of GM knowledge. Let the teaching begin!

 

[Tacoma]

Keep the serpentine brackets, there is a $100 adapter kit you can get (and I will post the name of the company when I find it again.. ) instead of trying to junkyard the BB brackets. Also possible to reuse the the 350 harness with some adapters (threads on Pirate about it), if you don't have the 454 harness. You WILL need the 454 ECM though.

Since you're going to open the engine up, an RV cam makes a difference.. headers if you have money to burn, at tow-rig RPM's I don't think they're worth the coin. Say goodbye to mileage though... hopefully the joy of torque will make up for it in your mind. It went pretty far in mine. I may have parts for you if you just want a stock swap.

 

[Corban_White]

I don't care about the mileage, this truck sees about 1000 miles a year. Point me to some threads on pirate or anywhere else. LMK what parts you have. I am in parts gathering mode right now. Well, I am really in parts figuring-out mode right now. Parts gathering will come as the money does.

 

[DaveB]

I have a 454 in the garage that came out of my Dad's truck, ran great when he pulled it. It had an oil change every 2-3K miles. It has been sitting in my garage under cover for a number of years. It has about 90K miles on it. I was saving it for a project but don't think I'll ever use it.

 

[cheepin]

Like said you will need the 454 ECM.You will have to open the harness up and modify it.Depending on what the ECM comes out of.The 454's system is simpler.They don't use a knock sensor or VSS.Atleast my 1 ton 88' 454 doesn't.

 

[Tacoma]

I've got a factory TBI manual to help with the harness.

 

[Corban_White]

So, to do the swap I will need the obvious 454, the ECM, injectors/throttle body, a bracket kit for the accessories, and some wiring harness mods. Is that it? Did they only put the TBI 454 in the 88-98 body style trucks? Or did they put it in some of the later versions of the 73-87 body style? Are the motor mounts in the same place? Can I get my ECM flashed/reprogrammed and have it work? Is there anything else I should know?

 

[jswainthug]

Probably a helmet because that thing is going to move!!! Cool swap I love BB's.

 

[mbryson]

So, to do the swap I will need the obvious 454, the ECM, injectors/throttle body, a bracket kit for the accessories, and some wiring harness mods. Is that it? Did they only put the TBI 454 in the 88-98 body style trucks? Or did they put it in some of the later versions of the 73-87 body style? Are the motor mounts in the same place? Can I get my ECM flashed/reprogrammed and have it work? Is there anything else I should know?

That same engine will be available in the '87-91 R & V series trucks (solid axle units--Suburbans, Blazers, crew cabs and cab/chassis trucks) as well as the G series and C & K Series (IFS trucks). I can't imagine GM re-engineering motor mounts, but you may want to check that. I'd be surprised if you need to swap from the small block mounts.

 

[Tacoma]

So, to do the swap I will need the obvious 454, the ECM, injectors/throttle body, a bracket kit for the accessories, and some wiring harness mods. Is that it?

Pretty much

Did they only put the TBI 454 in the 88-98 body style trucks? Or did they put it in some of the later versions of the 73-87 body style?

1987 is the first year, and they will have a goofy 1/2 serpentine 1/2 v-belt setup, which is why I recommend reusing the small block stuff. I found the magazine with those adapters in it, will post later tonight.


Are the motor mounts in the same place?

Yes, same place.

Can I get my ECM flashed/reprogrammed and have it work?

Yes, or you could come out here and get one from me. I may be convinced to part with a harness too.

Is there anything else I should know?

Know that the joy of torque is a happy thing.