melfice_mx Posted February 21, 2014 Share Posted February 21, 2014 Greetings, I currently have an 1971 240z with SBC 355/Vortec heads, 4:11 R200 diff and 700r4 trans. I used JTR kit for swap and everything is working great.. except for freeway RPM/Speeds. I have T56 trans out of 1995 camaro with everything needed for my swap, but not sure if JTR 700r4 crossmember for 700r4 will fit T56 or if i need to fabricate new crossmemeber. Any input would be appreciated. Thank you. Quote Link to comment Share on other sites More sharing options...
Mike kZ Posted February 21, 2014 Share Posted February 21, 2014 This what JTR's web site says: Transmission Crossmember, $65 specify if for T56 or T5, 700-R4, Turbo 350. T56 crossmember is 1" lower in center, and requires hammering sides of transmission tunnel. 280 Z car requires flattening of floor to bolt the crossmember to the floor. Quote Link to comment Share on other sites More sharing options...
78zstyle Posted February 24, 2014 Share Posted February 24, 2014 What's your highway rpm in your final drive? Quote Link to comment Share on other sites More sharing options...
melfice_mx Posted February 26, 2014 Author Share Posted February 26, 2014 Thanks Mike for answer. Highway speed in final drive is 70 mph at 3500 RPM. Quote Link to comment Share on other sites More sharing options...
Mike kZ Posted February 28, 2014 Share Posted February 28, 2014 With a T56 it will be around 1800RPM at 70 mph Quote Link to comment Share on other sites More sharing options...
rayaapp2 Posted March 18, 2014 Share Posted March 18, 2014 1800-2000rpms @70mph sounds about right with the T56. Which is right out of my cams healthy spot(with carb) so Im constantly using 5th in slower traffic. The cross member will need to be about 4" farther back for the T56 than the 4L60E/700R4(which is another inch or so farther back than a TH350). It also depends on which T56 you use. There are at least 4 length options in the US. Im using the LT1 style from a late 90's camero. There was a picture somewhere showing the different lengths that helped me a lot when determining if I needed to build a cross member while the 4L60E was still in the car. The common LT1 and LSx are the same length(different shifter location) but since I didnt use the LSx one with the adapter bits, I couldnt say how much longer it will be. This covers just the Chevy options I think. Quote Link to comment Share on other sites More sharing options...
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