cruznude Posted November 9, 2017 Report Share Posted November 9, 2017 A guy here in New Mexico was selling a Mazda rx7 rear end on craigslist in which he stated he was going to install on his roadster. Has this been done before? Would this work on a 620? What benefits would we gain as I own a 79 620 kc. Also, just a question which doesn’t relate to this subject. When switching manifolds, where can a Weber 32/36 carb gasket be bought? 2 Quote Link to comment
datzenmike Posted November 9, 2017 Report Share Posted November 9, 2017 If the Mazda differential is an H-190 (or compatible) it should fit BUT car differentials have 23 spline side gears and your truck axles are 29. They can be taken apart and swapped but the likely reason for the swap is that the Mazda differential has LSD. If it does the side gear cannot be swapped. On top of this the gearing is likely below 4 so not really a performance advantage on a heavy truck. Would need to see a picture, know if LSD or not and the gear ratio to even begin to guess about this. Also what are you looking for??? performance, LSD? mileage? 1 Quote Link to comment
Doctor510 Posted November 9, 2017 Report Share Posted November 9, 2017 A guy here in New Mexico was selling a Mazda rx7 rear end on craigslist in which he stated he was going to install on his roadster. Has this been done before? Would this work on a 620? What benefits would we gain as I own a 79 620 kc. Also, just a question which doesn’t relate to this subject. When switching manifolds, where can a Weber 32/36 carb gasket be bought? http://www.piercemanifolds.com/ 1 Quote Link to comment
flatcat19 Posted November 9, 2017 Report Share Posted November 9, 2017 The RX7 diff is not a straight swap to the roadster. Modding of the brackets and width need to be performed. http://spriso.com The info about the RX7 diff is archived. I ain't going hunting for it. Spriso does the modding service for roadster owners. Mazda diff being strong enough for a truck...probably not. 1 Quote Link to comment
carterb Posted November 9, 2017 Report Share Posted November 9, 2017 John Wallum in Oregon has built two for me. One for a 510. One for a 620. PM me for contact info. 2 Quote Link to comment
DHale_510 Posted November 9, 2017 Report Share Posted November 9, 2017 The attraction of the RX7 differential is usually the clutch LSD, disc brakes, and the 4 x 4 1/2" bolt pattern. Unfortunately few RX7s came with these. The relatively rare '85 and '86 GSLSE models were the only ones like this. They were coil sprung instead of leaf sprung so all the mounts are different. and they were wider wheel base than the older Datsuns. They are not really bargain garage find parts, but they work very well is you can adapt them. I think all the 620s had 6 bolt wheels so not even that part works. Dennis 1 Quote Link to comment
Mattndew76 Posted November 9, 2017 Report Share Posted November 9, 2017 It took me forever to find one for my 1200. Snatch it up and make it work. 1 Quote Link to comment
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