4 spd to auto, auto to 4spd

[Hotwheelsjr]

If anyone can answer this, I know ya'll can!!

Ok, so I'm working a deal to swap my 727 for a 4spd with a guy that wants my 727. We both have steel crank 340s (mine's a 70, his is a 71) and he was told by the guy that built his that he's going to have to machine down the nose of the TC for it to fit his crank. I was under the impression cranks were all drilled to accept an auto and you had to put a bushing in for it to accept a 4spd. Am I wrong? He's worried now that his crank may not be cut for an auto. He doesn't want to have to pull the motor to do any drilling and he's asked a couple of tranny guys he knows and they've said they can't machine the TC. Anyone know the scoop? Murphy has a way of jacking my plans up around every corner, so this has got me pretty worried now -- I REALLY want this 4spd.

 

[grumpuscreature]

Somebody is working with misinformation. You should be able to make the swap with no machine work needed. The torque converter snout centers on the crank register while the manual needs the pilot bushing. Not all cranks were drilled for a pilot bushing but they all had a crank register. The register size did change, but that was between '67 and '68 not '70 and '71. You may have to install a pilot bushing if you don't already have one. I believe that '72 was the last year that all cranks were drilled and had bushings installed whether they were manual trans or auto. Hope this helps.