[Half-Inch Stud]

Originally Posted by antique69lemans

I've been gathering parts for the same swap. Where did you get the speedo cup ? I machined one and used large muncie drive gear.. Have you determined driveshaft kength ? Theoretically it will be 3.25" shorter.

intend to buy a shorter 1350 yoked & Jointed driveshaft (~ 3.25" shorter than the present)

Speedo cup is an aluminum tube section and massaged to fit the stock TH400 Speedo.

[Half-Inch Stud]

Going to upload the sequence of photos showing the 4L80 install (did this after work today);

1. Converter and holder in place then Slide 4L80 under GTO behind Header to clear. Easy
2. Slide 4L80 forward to be near engine. Easy
3. Tip to add floor jack, Some effort. Added spacer wood was easy.
4. Spun Spacer wood to get some height. Easy

[Half-Inch Stud]

This is the most important activity. Hope to defy gravity here;

1. Pry front and put leg on tail to turn Spacer wood in it side, to get height. Easy
2. Added a second wood for stability. Easy.
3. Slide onto jack. Some effort but easy.
4. Slide further onto jack with additional front spacer(dolly) & it's mostly on the Jack!

During the 4 shots the bell is wedged on the headers. The Headers provide a sort of stability. The Headers also provide great grief in blocking the rise-up effort. The 4L80 is wedged up front an I'm liking that.

[Half-Inch Stud]

This effort is to get the Bell past the Headers.

1. Turn 4L80 Tail toward camera to get Bell to Get past Header. Easy
2. Going up, getting past Header is a process. Easy
3. Going up, getting past Header ( probability past, I dunno). Easy.
4. Probably past Header, and not so stable as it was, but Balanced. Easy

This was an activity of using a pry screwdriver on the Primaries//Bell to walk the Bell past the Header. Easy.

[Half-Inch Stud]

Last two install photos here, just walking the Jack up to get Dowel alignment, and Bolt it.

1. Added a Jack stand (safety first you know) to take the converter weight and provide stability while putting more height into floor jack. Bell wants to rest on flexplate and provides stability. Easy.
2. Put fine height tweak for dowel alignment, push forward Engaged! Easy. 4 Lower bolts in, then 2 upper bolts in. Easy. Jack Stand doing nothing.

1st connection was the Vacuum hose on the Driverside, then speedo cable. Speedo cable will be replace with a new longer cable later.

Jack stand & wood put away. Floor jack doing more work ofthen a rear crossmember for now.

Dip stick Tube was dry-fitted and cut about 5 3/4" for a nice underhood height.
Dipstick was cut and marked for drilling small holes to set back together with #2 screws.

5:25PM Time to take dog to dog park, eat and rest. Going to be dark soon. Today's upload done.
--> Tomorrow Sat ought be more hookup.

[Half-Inch Stud]

Dip Stick Tube is in. Under hood height is nice. Slipped into silicone rubber boot in 4L80 case nicely. Upper Bell bolt done tight with Tube bracket now.

--> Despite hugging the case, appears the dipstick Tube will touch the floorboard around the tunnel when the tail is set to the crossmember. More 1st gear noise I suppose. Think it will yield, and I will add a cut heater hose sleeve for dampening for best result.

Here's the dipstick cut-to-nice length difference. Cut, drill & screw is greatly preferred to re-bend-n-fracture the dipstick metal.

Notice 3 #2 screws are sufficient to hold Dip Stick to new length. Drilled & tapped stick. Peeped instead of nut.
Notice stamped reading are still relevant and readable.

Notice the Cooling Clips in the bag. New is good here, and Cooling lines (or Converter bolts) are next.

[Half-Inch Stud]

Decided on Converter bolt install before Cooling lines. Here's the bolts, washers sorted for uniform thickness, and install gaps.

1. This bolt washer photo show two types of stock bolts, yet I did not have 6 of the Stock long bolts, so 3 Lowes stainless bolts will do.
2. Converter-Flexplate gap (Converter slumps making gap appear bigger than when concentric.
3. Bolt type alternate for Stonk hole vs stretched hole. 3 carry TQ, 6 carry Converter weight.
4. Washer stack for Gap.

Helluva converter perch huh. This particular Converter takes long Stock bolts whereas the other Converter takes those short bolts. Well good thing the converter I picked can take long bolts: the gap to Flexplate is longest ever since there is a Bell adapter plate. No bid deal.

[Half-Inch Stud]

Cooling Lines dry-fitted and formed. Going for floorboard cooler. Here's why;

These 12 Volt fans were easily installed with mini zip ties. The soldered wiring is for max speed while the lower speed settings will be a later deal if wanted, but max speed is quiet.

The Cooler was laying Around (think the GTO has the same cooler in the Valence & that is coming out).
Non-adjustable clamps are my choice to go. Years of pulling this small stuff helps the project.

[Half-Inch Stud]

Cooler install. Clips for cooling lines came in, so install is as done as allowed until Crossmember get bolted in. oops no photo yet. okay now.

[Sirrotica]

Mark, did you use a gas convertor, or diesel? The gas has a higher stall than the diesel does, that's the reason I ask.

[Half-Inch Stud]

Originally Posted by Sirrotica

Mark, did you use a gas convertor, or diesel? The gas has a higher stall than the diesel does, that's the reason I ask.

Interesting. So I pulled both Converters & 4L80s from Gasoline: 1 Chevy Van, 1 2WD GM/Chevy Truck.

Both were pulled in 20 degree weather, 1 month apart, and I don't understand why it went so easilty compared to a warm/Hot Sunny day. Easy to lay on the frozen ground for sure.

[Half-Inch Stud]

Shifter is in !

Shifter will provide 1st, 2nd, 3rd and 4th. Column will provide Park, Reverse, Neutral and Drive. I dunno if column will provide 4th, 3rd, 2nd, 1st, and doubt it.

Photo of shifter is with Crossmember in place. Needs outer ends bolted but was no fuss; slid back of course.
Here's how it looks from the inside;

[Half-Inch Stud]

Had the time this eve to bolt the Crossmember.
Sure it has room to slide back a few inches. no biggie.

Had to drill hole pairs to set the stock Rubber isolation Brackets.


So that is yet another easy breezy thing to do.

[Half-Inch Stud]

Tonight was all about hooking up thr Column-Shift. This is whete the Dual-Gate would be a breeze. But since it is a Stick Car, The Column selects Park, Rev, Neutral, Drive.

These Photos show;
1. The Original bracket gets an extension to make the deal go. Oil Pump baseplate makes great stock.
2. The Original Column Shift Rod was straightened to reach the crossbar. Thie two photos show 1st Gear position, then Park position. Full range is way clear, and feels crisp.

I think it is all done, except for BUYING the shorter Driveshaft. Ebay seems to show 1350 Driveshafts for $220, while Dennysdriveshafts wants $720 for the Nitrous Ready Driveshaft. Geez I paid $380 for that Dennys 12 years ago.

[Half-Inch Stud]

Final photo; view of the Hurst Manual Shifter and the Column Shift Control.

Again, a Dual-Gate Auto car would be a breeze compared to this deal.

[Sirrotica]

Shortening the one you have would be cheaper if you have a shop locally that does that type of work. Since Bluebell is a fictional town, I wouldn't have a clue where in AL you are or what you're near...……..

BTW, nice writeup on the install procedure there Mark, you've proven that using a 4L80E in an A body isn't going to require opening the floor up like a can opener, like many people have argued.

Here's a picture of the two transmissions side by side so that anyone can see the 4L80E is only marginally larger than a TH 400 and installing one in most GM muscle cars isn't going to require destroying the floorboards, only minor dimpling. Also that a 4L80E in stock form with a shift improver kit will be more than adequate with 99.9% of the high performance street cars on this forum. The transmission doesn't need to be gutted saving only the case and replacing the inner pieces with expensive billet hard parts, that can only be done allegedly by maybe 10 people in the US.

Side by side TH 400and 4L80E:

[Half-Inch Stud]

Brad, Thanks, and evident in your photo, the 4L80 case prep ought be intentional to;

1. remove the Chevy peak, and keep the BOP sag at the top. (both my cases are different (one regular, the other HD, and both have the BOP sag under the Chevy peak). Your case doesn't have a full BOP sag, so seems odd to me.

2. remove the excess ridge along the case top.
3. REMOVE the case side ears as they will not pass any headers. I did and am a happy guy.

[Half-Inch Stud]

Tools put away until the Driveshaft install. So Temp Knob replaced with intended shift knob. Final interior shot;

[Half-Inch Stud]

I really should measure the driveshaft, for ordering.

Here's installed depth and excess (3.25") past the rear yoke;

And the Dennys Driveshaft (TH400) looks to be 52.5. to 52 3/4, so the Needed driveshaft is 3.25" shorter, or 49.5" to 49.3". Constant diameter is 3.5"

[Half-Inch Stud]

Ordered custom Driveshaft from Gary at Houston Drivetrain Services "okay we'll ship it tomorrow".

3.5" DOM (drawn on mandrel) seamless mild steel,
1350s
Yoke