My 4L80E Experience so far...
The 4L80E Overdrive ratio is actually .75:1, not .87
I finally mated my new 383 with a Hughes Performance 4L80E and slid it into my 81 Malibu yesterday. Tight fit - you need to pound flat the sheetmetal ridge that joins the firewall to the body, but once you get it in it has clearance on all sides. I had the smaller flexplate (153 tooth) and Vette starter and they will not work with the 80E - it requires the 168-tooth flexplate and a starter to match. Luckily noticed that Friday morning and had time for a Summit Saturday delivery!
Next is threading the headers and motor mounts in there. The motor/trans combo is still supported by the cherrypicker so it should make it easier.
Once I can set it down on the mounts, I need to fit the crossmember from G-Force Performance. It was meant to be for a T-56, and John is planning an exact version, but I need to send him pix so he can finalize the design.
Then it's on to wiring - the 4L80E has its own harness that has almost as many connections as my Holley Commander 950 MPFI! Part of it is that the harness (by TCI via GMPP) is designed to support both the 4L60E and 80E, so there are some unused wires no matter which you choose. I am just going to remove those. The tranny has 3 electrical connectors on it:
TISS: Transmission Input Speed Sensor
TOSS: Transmission Output Speed Sensor
Main Connector: Round snap-in connector w/about 20 connections.
Since I couldn't find a good local 80E core, I had to forfeit the $800 core charge from Hughes. With the GMPP Computer and harness, and the optional mechanical speedo adapter, my total for the tranny setup was $4890 delivered to Cal.
Some Engine Details:
383 ci
4-bolt GMPP HD Block with 'short fill' of Hard-Blok stiffener
All-forged bottom end by Speed-O-Motive
Edelbrock E-Tec 200 Heads, fully ported
Comp Cams valvetrain
Custom Comp Cams solid roller, 230/236 @ .050", .589/.602, 112
Vortech V-2 SQ S-trim
Bell intercooler (core: Bell 23"L X 6"H X 4.5"D, 34 down channels)
Holley Commander 950 MPFI, 50#, Race Upgrade
FJO Racing Wideband O2 Controller
NOS Cheater Kit (will start with dry 100HP setup)
Modified Hedman Husler Race Headers, Jet-Hot coated
Canton Racing Road Race Oil Pan and Accusump
MSD 6A
Starting target is 650HP at the crank, with no nitrous and ~8 lbs of intercooled boost at the manifold. After I break it in I'll try playing with pulley combos.