4L80E behind an Olds 455? - Please Help.

[68 D88]

I'm interested in installing a 4L80E behind an Olds 455. I’ve been combing this site for info, and from what I understand the ’96 up 4L80Es are the ones to be looking for due to the factory improvements. I have some specific questions I need answered if possible.

1) What year did the bolt pattern go from SBC/BBC (6 bolt) to the LS1 (7 bolt)?

2) Is there an adapter plate for the LS1 style 4L80E transmission to the BOP engine bolt pattern? I assume there is due to the LS1 T56 having been successfully attached to a Pontiac engine.

3) Is a spacer for the torque converter required when using the adapter plate?

4) Is it possible that a 4L80E (that was originally mated to a gas engine in a truck) will have the correct stall (1500 – 2500 rpm) for use behind a fairly tame Olds 455?



5) Will the 4L80E torque converter correctly attach to the Olds 455 flex plate? The TH400 torque converter uses three prongs to attach to the Olds flex plate, and cannot use one with six prongs due to a counter weight on the flex plate being in the way.

6) The cheapest aftermarket 4L80E controller appears to be the TCI, $659 at Summit. Is there a more affordable alternative? What years were the separate controllers available on the diesel powered trucks, and what components need to be removed from those donor vehicles?

7) What is the most affordable alternative for the speedometer?

The goal is to find a good used 4L80E, the newer the better, and put it behind the Olds engine in the most affordable manner possible.

[Steve Chryssos]

Good questions. I'll look into the BOP thing and get back to you.

[68 D88]

streetfytr68, were you able to find anything on this? Thanks.

[Steve Chryssos]

Not yet. I've got a call into Mark at Bowler Trans. They put a 4L80E behind a hemi in Poison Dart. So I figured that I should start there. I'll talk to him tomorrow.

[Steve Chryssos]

Here we go. Give Bowler Transmissions a call and ask for Mark. Says an adapter for that application is about $240. Crank to flexplate spacer, bellhousing adapter and hardware. Please tell him that Steve at Twist Machine referred you.

http://www.bowlertransmissions.com/
RR#4 Box 148
Lawrenceville, IL 62439
Main Phone: (618) 943-4856
Fax : (618) 943-3690