BigT-DK Posted November 5, 2007 Share Posted November 5, 2007 I have just had a look two overdrive-boxes a mate has on offer...(for my spitfire)they are the type with an extended selector housing and are bolted up to D-type overdrives with round out-put flanges.comm nrmbs seem a bit odd.KF 15321 (this a US-spec GT6box according to information on this site?)FNR 911197 (?????) this one maybe has more layers of nmbrs...reconditioned maybe?Can anyone shed light on what these boxes came out of?anything to consider during rebuild ? will in time be mated to a lightly tuned 1300 engine. Link to comment Share on other sites More sharing options...
Richard B Posted November 5, 2007 Share Posted November 5, 2007 The GT6 gearbox will have certain things wrong for the 1300. The incorrect input shaft (diameter & splines) and the wrong bellhousing. Not sure about the other box.I would look at swapping / trading the GT6 box for a 1300 Mk IV box or have it rebuilt into such a box. The 3 rail Mk I-III box's do not have synchro 1st whereas the GT6 box's and the MKIV 1300 box do. Link to comment Share on other sites More sharing options...
BigT-DK Posted November 5, 2007 Author Share Posted November 5, 2007 yep,that´s what confuses me... the number on the gearbox suggests it being GT6 but the bell-housing attached is a "spitifre" type... Both boxes have what seem to be the correct bell-housing / input-shafts etc. (they look identical)I guess the numbers stamped on the boxes refer to some sort of rebuild at some point? Link to comment Share on other sites More sharing options...
Nick Jones Posted November 5, 2007 Share Posted November 5, 2007 Case numbers should be treated with great suspicion as most of these gearboxes have been rebuilt at least once. A GT6 casing could be used to build a 4 synchro spitfire gearbox for example - I think we need pictures.....Nick Link to comment Share on other sites More sharing options...
BigT-DK Posted November 8, 2007 Author Share Posted November 8, 2007 ok ... Link to comment Share on other sites More sharing options...
Richard B Posted November 8, 2007 Share Posted November 8, 2007 Well there both 4-pot box's (now). The KF box was from a GT6 so has synchro 1st same as MK IV Spitfire. If the casing for the other box is 1/4'' shorter then this is from a Spitfire I-III. If so I would keep the KF box and sell the other one.If the casings are the same length, then it does'nt matter they're both have synchro 1st. Link to comment Share on other sites More sharing options...
Nick B. Posted November 8, 2007 Share Posted November 8, 2007 Well - I took a look yesterday too. One is stamped KF, which indicates a GT6 MK3 US market. Still I doubt that it is a GT6 box as it has the same number of splines on the inputshaft as the MkIV box next to it.The other box has been in the hands of a rebuilder, but you can see the original number under the rebuilders number - and that is a FH box - see photoRegardsNick Link to comment Share on other sites More sharing options...
Richard B Posted November 8, 2007 Share Posted November 8, 2007 FH = Spitfire MkIV-1500, as it's a 3-rail it's a MkIV. So they're both good! Use one, sell the other...... Link to comment Share on other sites More sharing options...
BigT-DK Posted November 8, 2007 Author Share Posted November 8, 2007 ok then... that is an overdrive box sorted then.... should I consider a diff-ratio change?-my 4.11 diff is a bit noisy with the top up.. Link to comment Share on other sites More sharing options...
thescrapman Posted November 8, 2007 Share Posted November 8, 2007 BigT_DK wrote:-my 4.11 diff is a bit noisy with the top up..Well put the top back down then, that is what everybody else does. ;DColinp.s. a 3.89 or a 3.63 may make it slightly or a fair bit more pleasurable dependant on what engine you have. Link to comment Share on other sites More sharing options...
.thumb.jpeg.b15b81ef10abeea1c3039ae03c4a9f3a.jpeg)
Recommended Posts
Archived
This topic is now archived and is closed to further replies.