904 to 518 swap....??

[pastortom1]

This has probably been covered here before.........

I have a nice 1972 904 behind a mod-318 with a 3.55 posi......I'm just tired of not having another gear for cruising...... I've considered a new tailshaft overdrive, but it just seems too expensive...........

Can someone tell me more about the a-518 I've heard mentioned.....Would it shift with nearly the same ratio's as my 904, with the ADDITION of an overdrive?..........Is it 4 speeds or 5?.............And what, short of a probable driveshaft shortening, would I be up against to swap them?

Will the stock linkage match up? Rear motor mount? Neutral safety switch?

Could you guys walk us through the reality and specifics of the swap? :read2:

 

[tophat]

What car is it going in? As far as I know a 500 \ 518 will not fit an A body (I think B and E bodies too) without cutting out and refabbing the whole torsion bar cross member. The overdrive unit is in the "tail housing" and has no chance of fitting in to the area that the tail of the 904 is in now. I think the same problem comes up with the "hang on the back" overdrive units too. Not saying it can't be done, just that its not "bolt in". Of course with torches and a welder anything can be made to fit.

Somebody makes a generic monkeys 4 speed overdrive with an LA bellhousing pattern, but it is still a generic monkeys transmission.

TopHat

 

[fishy68]

I haven't done it but this topic has come up before. Do a search on it and you'll find several threads on it. Some guys say it can be done fairly easily.

 

[speedyb-cc]

Yes as TopHat said it's not something you should attempt without help from someone who knows how to rebuild the cross member top half after you cut most of it out. This is the torsion bar mounting point and an important structural point of the frame. You also have to build a lower cross member to mount the tranny. I have looked into this as I have a 518. If you decide to do it PACT 700raptor.com has a kit to make the overdrive work off of the hydraulics and electrical so it shifts pretty much automatically in and out of od. I have some pics from a guy who is doing the swap, pm me if you would like them.
Bruce

 

[superdart]

I already sent info to Pastortom about it, I think. But here is my thread on my install.

http://www.forabodiesonly.com/mopar/showthread.php?t=27244

I wish I wasn't so busy when it was the shop. I wanted to get progress pics to show people the modifications before the trans was bolted in.

Shouldn't we have a sticky thread for the 518/500 install topic?