big block in a 39 GMC COE

I am just starting this project and plan to put a late 90's 454 in the truck. What electronics help do I need and what is the best way to mount the engine? I am going to use a late 4L80 trans.

 

Can't help you Chris on the electronics, or mounting the 454 just yet. Tell us what you are planning to use for a frame/ch***is, and whether the engine will mount under the COE Cab, or behind the cab. That might make it easier to help you out. I kindof doubt that there would be room to mount the big block under the cab.

 

I mounted a 500 caddy under the floor of my 40 chev. COE, no problem, stock frame, Dodge motor home I beam, lotsa room!!

 

cris lets see your project, it sounds cool.

 

I am back on this project after a time out of the country. I have a 91 G30 ch***is, 98 454 and 4L80E trans. The motor is in the stock location on the ch***is, more or less where the 39 location would have been. The cab has been extended 44", chopped channeled down, the fenders have been cut on the bottom and moved up. I have finished th edog house over the motor. It takes a lot of the foot room, but it's livable. The next problem is the radiator and core support. There was nothing there from the cab or ch***is so I am starting from scratch. I want to see what the original looked like so I can get close to a factory look.

 

GREAT project! The engine pic looks like it has the harness intact. If you have it, and the ECU, you can easily modify the harness to work as a stand alone. If the 4L80 is not the original (wouldn't that have had a 4L60E?), you can have the computer re-flashed, and rewire the trans harness. The 4L80 has two fewer selenoids than the 4L60E, so the pin out is different.

Contact Brandon at "LT1Swaps.com" for all the info you need for harness mods, wiring diagrams and pin-outs. That stuff is free on his website, and he re-flashed the ECU for my Diamond T (I'm using a 6.0 LQ9 from a 2500 HD 4x4 and a 4L60E from a 2WD van) for 75 bucks, including return shipping. Scream'n deal, and a nice guy.

Brian

 

I was able to get a harness and ECU from Howell Engine Developments in Michigan. They have everything I need to get the fuel injection, ign and trans going with no emission problems.

 

Hey Chris,
Nice project! Cool to see another '39 GMC!
I wondered about my front cab mounts,the ones under the side vents. Mine kind of looked after the fact ,suitable fix type of thing and not too precise. Yours are exactly the same. Neat!!!

Kelly

 

I am doing a 46 GMC with a 454 in it.

 

hey chris....I'm also in san diego and also doing an early gmc coe...mines a 40. do you have or need parts for your truck....i have some....