AFTER TWO YEARS, NEARLY 400 POSTS, AND ALMOST 30,000 VIEWS
MAYBE IT'* TIME FOR A NEW THREAD... FOR THE LATEST, SEE THE "NAME PONTIACJEFF'* TWIN-CHARGED BONNEVILLE PROJECT"
It'* going in a '96 SSEi in conjunction with the Twin-Charged 3800 SII.
The first thing that jumps out is the enormous side cover and general girth of the -80. In stock form it is rated at a conservative 305lbs.ft. torque capacity. There are a few Caddys pushing WAY more than that thru. I'm sure in stock form it will handle 450hp and 450lbs.ft. I estimate the hard parts to be good for 550-600lbs.ft. before hard part breakage occurs (using GMs 2:1 margin of safety factor). I will be rebuilding it using old transmission tricks of the trade for shift improvement and clutch life. The 98-up SSEi pcm and program with Caddy shift tables in place of the -65 tables will be used to control it. All inputs and outputs are identical b/t the two transmissions. A custom trans harness will be needed to add the necessary wires and run them to the pcm.
Of course, custom mounts will be needed, as will BOTH
axles. Both -80 axles have a female inner joint (the differential uses an output shaft as well). I will be installing my EP Limited Slip Differential in the transmission before final assembly.
As for fitment, a new tailshaft support bracket will be fabricated, as will front and rear trans mounts. I might use a W-body-style rear mount and add upper dogbones if it looks like it will be easier.
The rear knock sensor WILL
need to be eliminated and a little grinding necessary for the rear lower bellhousing bolt. The block hits the trans (barely) and the bolt holes do not line up. I already have a strap/bracket in mind for this issue.
Both the block and trans bolt holes will get a helicoil insert, enabling me to bolt the strap/bracket and tie the two holes together. (The block was drilled and tapped for a 10mmx1.5 bolt to line up with the -80 bellhousing)