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Discussion Starter #1 (Edited)
mostly curious here..
Someone posted negative about this type of AA adapter for a 420 or 465 GM trans converstion and I wondered what the drawbacks are?
Seems like it has many more advantages to me. No driveline or axle mods?
1. You keep the stock drivetrain postion I assume ? ...correct?
2. For a V8 conversion does it move the V8 far enough forward for clearance on the valve covers.4" needed if IIRC.
Just interested in the pros and cons.
Here is the page from AA.. http://www.advanceadapters.com/catalog/063.html
crummy pic from AA site..
 

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I have put in both of those and both trucks run well. Many rubicon trips and still ticking. some stud lossening at the back of t-case on both rigs. It allows the 4 spd. drive flanges to clear the sm420 unlike the plate adapters. It also has the advantage of the spud shaft uses the last bearing under the cone whereby the plate style don't. Both rigs have sb v8's and I believe mounted as per the A/A directions for the chevy sb conversion using their mounts.
I have encountered a problem with my old school 420 adapter . it does not clock the t-case up and the wings of the A/A rear mount don't sit level , and I am not going to hang the orion off it all twisted up on 1 side. I am considering using different thickness mount on the passenger engine mount to twist the whole thing back to level but it seems oakey to do that .
 

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The only drawback that I mostly hear of is of the extra length compared to the plate style adapters. Kinda important on the rear driveshaft issue if someone is to consider going SOA. That and I have seen some of the earlier spud shafts bust and also have seen a couple of the adapters crack. But that could of and most likely was due to how it was mounted.
Driveshaft mods are necissary due to the length of the adapter.
This adapter has nothing to do with engine placement. It helps to have it all bolted together while stuffing a V-8 motor i.e. a bit farther forward to help with the rear shaft angle/length. Clearance with tub issues ect.
Basically your looking at driveline mods behind a stock 6 or a V-8 depending on your last tranny/tc combo lenght.
One nice thing about it is that it has no front output flange to tranny interference. And there is a machined mounting surface built in to the adapter
if one chooses to mount it that way and not the plate type off the back of the t-case.
 

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I ran this adapter behind a 2F/sm420 for years. I just sold it this summer when I swapped in the Toybox. It held up great to a lot of miles with virtually no noticable wear on the shaft.
Advantages:
1. Design. The input shaft to the transfer case is supported by bearings on both ends, unlike the plate style adapters which are supported only on the tranny side.
2. PTO winch can still be used.
3. Length can be an advantage if swapping in a V8.
4. No grinding of the transmission or output flange needed.

Disadvantages
1. Length. Long adapter can be a disadvantage if keeping the F/2F or if adding reduction boxes.
2. Driveline modifications required.
3. Shifter modifications or tranny hump modifications required.
4. Cost. Usually more expensive than plate style adapters.

If choosing this adapter to shift the drivetrain forward during a V8 conversion, I'd seriously consider saving your pennies for a Toybox / RockBox. For an extra 1.5" of drivetrain length you can add some serious gear reduction.
 

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I went through this same dilema 2 yrs ago and decided to go with the plate style (thx Mike!) to keep my rear driveshaft length. With the plate a stock BJ60 front cv shaft now bolts right up to my rear diff.
No more vibes for me! :D
 

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Discussion Starter #6 (Edited)
great replies guys... so my main question is . using this adapter on the stock t-case location, will it move the trans forward enough (SM420 ot 465) to accomadate a small block Chevy without hitting the firewall . I have heard it solves that problem.
Or does the drive train still need to be moved. I am unclear. If you have to move the drivetrain this adapter would be obsolete to begin with.
 

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One length I KNOW is identical...

The AA bellhousing to the stock 4-speed tranny and t-case is within 1/4" of the stock GM bellhousing, SM465, plate adapter, and 3-speed tranny. I didn't even change the mounting holes for the AA propellor mount when I made that swap.

If my poor memory serves me correctly, the swap using a 2F, stock 4-speed, stock t-case and keeping the 2F with a 3-speed bell, SM420, plate, and 3-speed t-case is also the same....believe that's true....

Ideally, V8's should be pushed forward enough to keep the fan close to the radiator, or to keep an electric fan just off the water pump pully. This provides an inch or so of clearance at the PS valve cover off the firewall. (As you know, no two conversions are identical...mine is actually being remounted soon, pushing another .5-.75 forward...)

As critical as anything with the 420 and 465 conversion is the clearance of the shift tower with the stock heater box....it can be VERY tight...
 

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I think that planning your drive train install around the driveline lengths and positions isnt too good an idea. For one thing, if you are running that adapter with an SM420, your shifter will end up way too far forward. Probably infront of the firewall.

I have a Chevy motor, SM420 mated to my 3 speed t-case with the flat plate style adapter, and my drivelines came out pretty close to stock. In fact I just flipped them front to back and drove it like that for a while. The shifter, with the motor pretty much as close to the firewall as I felt comfortable, still comes out of the floor under the front of the heater, and I had to modify my heater a tiny bit to work.









I don't like the idea of that adapter as much as the plate adapter since it makes the drive train longer, which in an FJ40 isnt desirable.

good luck with the project.

-Dustin
 
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