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| Factory trans adapter & spacer https://slantsix.org/forum/viewtopic.php?t=68023 |
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| Author: | volaredon [ Tue Dec 17, 2024 3:32 pm ] |
| Post subject: | Re: Factory trans adapter & spacer |
Yup I need to check that on mine, think I'm gonna have to hit up a machine shop and have the engine side of my crank adapter for a '68+ /6. |
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| Author: | vitamindart [ Fri Jan 03, 2025 9:25 am ] |
| Post subject: | Re: Factory trans adapter & spacer |
I know I have been looking for one for a while. would love to find an aluminum one. I know the guys at Gill Welding have it on their to do list. not sure when they will get to it. an A500 behind the slant would be great for me. |
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| Author: | Dart270 [ Fri Jan 03, 2025 2:22 pm ] |
| Post subject: | Re: Factory trans adapter & spacer |
I put an A500 behind the Slant in my 68 Dart in 2001 and ran it until about 2017. Except for its durability (with the shift kit I put in it), I feel it is a pretty bad transmission in a car. It is a really heavy truck trans (at least 50 lbs more than a 904) with tons of parasitic loss. I barely picked up MPG even with the lockup converter - about 10%, and it was not faster in the 1/4 mile even when going from 2.94 gears to 3.91s. I could never get a converter made that would stall above 2200 RPM, after 3 somewhat expensive tries. It is a big fat trans in back and so the cutting to the car was pretty involved, including completely remaking the upper and lower X-members. All this stuff was carefully measured and tested. When I put the 200-4R in with the Wilcap adapter plate and a 2500 RPM stall (LU) converter, I picked up 3 tenths in the 1/4 (mid 13s to 13.1 - turbo) and about 1 more MPG, and the trans/conv is smaller and about 30 lbs lighter than the A500. Several other GM trannys are available with pros and cons... I would be happy to discuss your application/desires and options, but my standard answer now on the A500 is to avoid it unless you have a truck and don't care about efficiency. IF you have a good one in hand and can find an affordable adapter plate, and you do not want much better perf than a 904, then go for it. Lou |
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| Author: | Reed [ Fri Jan 03, 2025 5:01 pm ] |
| Post subject: | Re: Factory trans adapter & spacer |
Quote:
I put an A500 behind the Slant in my 68 Dart in 2001 and ran it until about 2017. Except for its durability (with the shift kit I put in it), I feel it is a pretty bad transmission in a car. It is a really heavy truck trans (at least 50 lbs more than a 904) with tons of parasitic loss. I barely picked up MPG even with the lockup converter - about 10%, and it was not faster in the 1/4 mile even when going from 2.94 gears to 3.91s. I could never get a converter made that would stall above 2200 RPM, after 3 somewhat expensive tries. It is a big fat trans in back and so the cutting to the car was pretty involved, including completely remaking the upper and lower X-members. All this stuff was carefully measured and tested.
Interesting! Thanks, Lou! I really appreciate your first-hand experience. I have a truck with 3.9 gears. My truck still has the 727 it was built with. I still need to do the weighing and the math, but I suspect the A500 weighs close to what the 727 weighs. My motivation is to get my highway RPMs down from about 3400-3600 to somewhere around 2500-2600.When I put the 200-4R in with the Wilcap adapter plate and a 2500 RPM stall (LU) converter, I picked up 3 tenths in the 1/4 (mid 13s to 13.1 - turbo) and about 1 more MPG, and the trans/conv is smaller and about 30 lbs lighter than the A500. Several other GM trannys are available with pros and cons... I would be happy to discuss your application/desires and options, but my standard answer now on the A500 is to avoid it unless you have a truck and don't care about efficiency. IF you have a good one in hand and can find an affordable adapter plate, and you do not want much better perf than a 904, then go for it. Lou I am suprised your experience was the A500 had more parasitic loss than the 904. My understanding was the A500 is essentially a 904 with a New Process overdive stuffed into the tailshaft housing, but I have never taken an A500 totally apart to verify. Rebuild parts even interchange between the A500 and the 904. |
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| Author: | volaredon [ Sat Jan 04, 2025 7:01 am ] |
| Post subject: | Re: Factory trans adapter & spacer |
I also have an original one of these, and when I got it I remember talking to Lou about what had to be ground out around the starter but don't remember what was said. Other than it "wasn't that much" grinding. I did hold the crank spacer up to a newer v8 crank (what I had convenient) and yeah I'm gonna have to send that spacer out to a machine shop to have wallowed out to fit the 68 up cranks.... No I'm not selling mine. I have everything else I need here to put it to use. Haha... I wish I knew someone around here that could 3D scan it... Plans are like Reed, as I too have a /6 truck and an A500 that im probably gonna mate together.... Though at present my truck still has its original 3.21s in it I don't know how much I might gain with the OD of I leave the rear end alone. . |
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| Author: | JR [ Sat Jan 04, 2025 9:09 am ] | |||
| Post subject: | Re: Factory trans adapter & spacer | |||
My situation is a bit different. I actually need the weight of the cast iron adapter. They actually added weight to the original chassis because it was too light. It will get done/restored someday when time permits. Until then I am collecting parts.
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