are the GM X frames in a 58 caddy and 58 impala the same? im gonna put a new ****** in my 58 caddy and the crossmember for the x frame is offered for the impala, was wondering if it would fit in the caddy...
No the frames are most certainly not the same...Two entirely different animals, with entirely different dimensions. What transmission are we looking to swap in the Cadillac, anyway? Your bellhousing-to-back-mount dimension of whatever type of transmission You´re using would determine the final placement of Your transmission crossmember on the frame.
Shouldn't be too tough to fab up something, what ****** are you using? Short of a manual conversion the stock Hydramatics aren't too bad.
According to my sources, TH400´s come in three different bellhousing-to rear mount -lengths, as well as 3 different total lengths, involving three different lengths of tail shafts, as well. On a TH700R4, the bellhousing-to-rear mount distance will be shorter than on a TH400, and they come in two different total (bellhousing-to-output shaft) -lengths. I´m in the process of fitting a TH700R4 into a ´58 Impala frame in place of the original Powerglide. As the 700R4 is longer than a PG on both accounts, looks like I´ll be moving at least the rear mount, if not the entire trans crossmember, further back in the frame some, as well as shortening the driveshaft to match the increased total length of my replacement transmission. As I understand You´re contemplating on replacing Your existing TH400 mounted behind the 454 in place in Your Caddy frame with a TH700R4. Likewise, Your best bet would be to figure out the differences in dimensions with Your existing transmission as opposed to Your replacement on hand, and go (=fab) from there. I have this pretty comprehensive list of specs on various styles of transmissions that I got from a gentleman from Chevy Talk when I first got to planning my own 700R4-swap. PM me if You´d like to see that, I have no idea how to post it on here. PS. What did You use for motor mounts in between Your 454 and Caddy frame?
i bought the car with the 454 in it...i dont know what they used...i can look...i asume its a motor mount...r u asking me what kind? let me know and if i cant tell u ill shoot u a pic
Just asking, as every BBC into a ´50s -Caddy -swap I ever heard of before supposedly required home-made motor mounts. Somewhere within the last year or so though, I recall hearing about someone making and selling them commercially now.
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