[pbbelly]

I got the NV 4500 today. After tons of searching and reading on 4btswaps.com I found several places where it was suggested that you can use an SM 465 bellhousing with an early NV4500 (the pre-'95 NV4500 transmissions used the same pilot diameter on the front bearing retainer as an SM465, later ones were larger there and had other differences as well) and just drill and tap the ears of the transmission to match the pattern of the bellhousing but, no one ever said that they had actually done this and there weren't any pictures posted either(at least that I found). I went to look at it with this in mind. I stuck the 465 bellhousing on the front of the transmission and can see absolutely no reason it wouldn't work. I may need to be careful with bolt length-especially if I try what I am about to suggest.

I've read a lot of discussion about the 10 degree lean and whether you should leave the engine leaning or lean the transmission etc. I would prefer to have my engine sitting upright in the engine bay if for no other reason than to avoid answering the question "why is it leaning?" every time someone looks under the hood. I am not crazy about leaning the transmission either, but would prefer that to a leaning engine and I don't believe that it would effect a manual transmission in any way. I am concerned about tunnel clearance though, but this may not be an issue at all.

On the four hour drive home from picking up the transmission I mentally installed it two dozen times. The thought occurred to me that since I am drilling the front of the transmission anyway, why not rotate the pattern 10 degrees in the opposing direction and then I could have a vertical engine and a vertical transmission too. I did a little bit of back-of-the-envelope math* and it looks like the holes would only move about 7/8ths of an inch from where they would be if I were drilling the pattern to mount the bellhousing square to the transmission.

It will likely be a while before I proceed with the drilling of the transmission. I have a ton of other things to do before I am to that point, but when I do I will document the process with pictures and post them here.

Am I overlooking some obvious pitfall? I can't think of any reason not to do it this way, assuming that my some of the holes don't fall too close to the edge of an ear. I am pretty certain any of the holes would anywhere near breaking through into the transmission case, but that wouldn't be a deal breaker as long as I am careful with bolt length and thread sealant and there's thick enough material there.


*assumes an approximate 5" radius of mounting hole from center of bellhousing hole-it is probably a little longer than that: 5xTan10=.88