I know this will sound a little unusual but I have a project that I am wanting to take on and I am wanting to put a inline 250 6 cylinder in a 1994 silverado that has a 4l60e or 700r4 and 4.3 liter already in it..... Will the inline bolt up to the transmission and what all will I need to change out for this swap.....

 

If you bolt up a 250 cubic inch motor to your 1994 Chevy, the motor might outlast the pickup. No I'm not joking at all.

The 250 is/was a ROCK SOLID motor. Of course, being a straight Inline 6 cylinder, might mean issues with interference with the fan and radiator in a 94' Chevy, but possibly not. They were common, along with the 235 Chevy mill back in the 1960's to 1970's, often bolted up to a three speed transmission, usually mounted on the steering column, or a ."3 on the Tree". Lots of half-ton Chevy and GMC pickups had them, Back then four wheel drive pickups were rare, but the old Chevy Blazer was 4x4. I-6 or V8, no V6.

If you live in a state without insane smog laws, its probably doable, but I think you'd be looking at a floor shift transmission, like a rock-crusher Muncie, or a Saginaw not an automatic, unless a three-speed or four speed non-OD, auto transmission would work for you. Think it was a TH250 and TH350 automatic. Still want a Chevy I-6, they had the 292 I-6 motor back then too

Might be an adapter for the 250 GM mill to your transmission but I dont know were it might be found. As a professional driver, I CAN tell you that almost all semi-trucks run inline 6 cyclider mills nowadays as they are inherently balanced motors, so they can run for a very long time, compared to a V-6. The 4.3 is just a 350 with two cylinders gone.