have beefed 727 whats good o/d trans?

[drivers mopars]

whats good o/d trans in place of my 727 in a c
body? will it bolt in?
do i need to change converter?
dont need lockup converter,
best years of trans to get, how will it work with my a/t shifher on the tree?
do i need to change cross member?
drive shaft cut?

[tsteiner61]

The 518 would be the logical replacement if you want overdrive. Here is a list (I'm not sure if it is comprehensive, but it is a start) of modifications to switch from 727 to 518.
1. New trans brace. The tailhousing is completely different between 518 and 727.
2. Modify driveshaft length. I believe the 518 with it's tailhousing extension is longer than the 727.
3. Converter change from non-lockup to lockup??? Not positive on this one, but I don't think they started making the 518s until after 1977, so they would probably all be lockup style.
4. Electrical hookup for overdrive, it is electronically controlled, by a solenoid, I think.
One positive, I think it should work with your tree shifter, because I believe the front end is basically the same as 727. It will bolt direct to A or B engine, and I think the linkages are the same too.

Here's a quote from the 2001 Mopar Performance Parts catalog:

"Requires major modifications on passenger cars."


Another option is a Gear Vendors unit, but it's really pricey ($2500). It will bolt right to your old crossmember, but you will still have to shorten the driveshaft, and there are still electronic controls involved. Another benefit is switching to manual shift mode, although it is not entirely as advertised. It is really semiautomatic, it shifts out of low automatically, even in manual mode, then you shift the other 5 gears.