I have a 98 Chevrolet Cheyenne Full size pick up. SWB with a 4.3L V-6 and I want to know what kind of tranny I have. I have no clue. It is automatic. That is about all I know about it. Help me out please......Also could you tell me if a 305 could mate to it if I got rid of the V-6.....thanks

 

4l60e i would guess....
the 4.3 block is based off the 350. its pretty much a 350 block with the front 2 cylniders hacked off, so the tranny mounting points are the same.
so i would guess that a 305 would mount up, yet why you would want a 305.......
you will be able to find out some more info on fullsizechevy, as that site deals with older trucks (pre 99, ls1 based engines)

 

4L60E.....
ANY smallblock (and MOST bigblocks) will bolt to that trans pattern....
if you are gonna swap engines skip the 305 and go for a least a 350....if you can find one get a 400 truck block, drill the steam holes in a set of Vortec heads and bolt those on

 

ANY rear wheel drive, with the exception of the heavy trucks, that GM makes with an auto has some sort of 4L60 in it. The bell housing may be a little different, but it's the same tranny. Yelo is right, that 4.3 is just like the 350 minus 2 cylinders. That means, if you wanted to build a hell of a sleeper, you can get pistons, cams, heads, rods, and some other stuff for it and have a pretty decent motor.

 

I dunno why I wrote 305 I meant 350! If I wanted to put an ls1 in my truck could I use the computer on my truck now or do I need one specially for the ls1. Can I use the computer from a vortec v-8 out of another truck? Is there any problems with running the ls1 with a 5 speed tranny as aposed to a 6 speed? Thanks also what would be needed as far as fuel goes. Do I need to up grade? What can I spare from the fuel set up that I have right now? thanks again!!!!!