'61 cruise o matic AOD replacement?

P

Philt

Active Member
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Oct 18, 2017
Thunderbird Year
1956
Hello All,
Refurbishing the drive train in my recently acquired 61 convert. Rebuilt the differential, new u joints, tranny and pinion seals, new leaf springs and bushings. Hope all this gives a nice cruiser for some all day highway cruising. Front suspension was rebuilt by the PO.
The 390 is a strong motor but it seems to rev a bit higher than necessary for 75 mph.
Thinking of a different gear ratio in the diffy or a modern AOD tranny. Any suggestions?
Phil in Tenn
 
Hi Phil. Agreed, at 75 the engine will be revving pretty high and another gear would be nice. I haven't looked at options at this point as it's down on my list...

I did find one set of specs that indicate that the torque curve on a 390 increases up to 3000 rpm then drops way off, and horsepower increases to 4000 rpm and then drops way off. So staying in the 3000 rpm sweet spot would be great!

Doug
 
The AOD swap is something I highly recommend. My 64 has this behind a 351W stroker, with 3.50 rear gears and cruises down the road very nicely. 70 MPH at 2050 rpms. If you do the AOD you will need the TV cable kit sold by Lokar or if you go with the AODE or 4R70W you will need an external electronic trans controller.. I know this is an old thread but this is one mod I would do if the transmission is needing attention.
Take care
Ed
 
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