I need help with the input shaft fitment of a new TKO600 five-speed installation in my 1968 Mustang equipped with a stock 390 with a stock Ford crankshaft. The TKO input shaft is too long and splines hit the bronze input bushing. When bolting the new transmission to the stock Ford GT/CJ bell housing (C6OA-6394D), the input shaft interferes with the input bushing with about .060” before the trans and bellhousing meet.
I ordered the TKO600 with the short input shaft option for Ford FE engine. The TKO600 as delivered, has the distance from the transmission mounting surface to the tip of the input shaft at 6.672”. The 428CJ big in-big out (RUG-AE2) close ratio top loader I am replacing measures 6.03”. That is a .642” difference. I was expecting new transmission to be a complete bolt-in and not to be this far off.
The stock Ford bronze bushing is fully seated into the crank flange. The bushing has always sat approximately .100” proud of the flywheel flange, is this normal? This old configuration has functioned perfectly in this car with this top loader for the last 39 years.
For a solution, it may be possible to remove the bushing and machine a step relief in the backside, outside diameter and move the bushing deeper into the crank flange. The pocket depth of the hole in the crank flange in deep enough to accept the current (short) input shaft. There must be a two diameter step in the crank flange hole.
I do not want to disassemble the transmission and have the input shaft shortened at the splines. Is there a better way?
Is the 6.03” input measurement from my Big In/Big Out correct? I have searched for this measurement and have not been able to confirm the 6.03”.
Did I really receive the short FE input option? My vendor said that I did and that I have an unusual transmission and bell housing.
Do 390 top loaders have different input lengths than big in/big out 428CJ close ratio top loaders?
I need some expert input please, summer is almost over and I have not driven my Mustang this year.