You should be able to use your original fork with the truck bellhousing but when you get a truck bell measure on both the distance from the center of the hole the trans goes through to the center for the ball that the fork snaps in,if the measurements are the same your original fork will work in the truck bellhousing and if they are different then you will have to make the truck fork work. I think after 38 that measurement should be the same on all bellhousings,when I was putting in a 235 in my 37 p/u I found that the measurement was different on the 37 on back then the 38 on up due to the different type of pressure plate and clutch system that was used but after 38 they are the familair type used untill the late 70s ?. Jeff