A500 42RH Crossmember template?
I installed a 42 RH in my 1970 Dart 2 years ago and have driven the car 13,500 miles so far. I have a few suggestions from my experience.
It's not just the shape of the crossmember that is important, it is also how heavy the material used is. The USCT crossmember (which must be modified to use with any A500 trans) is REALLY HEAVY. This seemed odd to me. I had the help of a fabricator/race car builder friend and he knew why right away. To have the trans correctly located it is necessary to cut out the hoop of crossmember that follows the trans hump out. You can leave a bit of it in place and insert a heavy band and weld it all up, but it is never going to be as strong as what you cut out. You have to also remove material near where the cross member bolts are and as shown in post #38 move the drivers side inner bolt outward, along with the bolt tube in the frame, to clear the bulge in the side of the A500. This is a BIG DEAL because the torsion bars put serious strain on the overall frame member that tries to tear things out downward in the middle. If you don't get this right, over time it will distort the whole frame member side to side. My friend has built a few C-body wagon race cars and they don't even have a loop over the trans tunnel. Instead they have a really beefy transmission cross member that is seriously attaches to the frame members that carry the torsion bars - that is why you have to take the tension off the torsion bars in a C-body before you remove the crossmember. If you do not, if you let the car sit for awhile, when you go to put the crossmember back in you will find the the torsion bars have bent the frame down in the middle. Although I have not confirmed this with USCT, I believe that this is why their cross members are such heavy material, and why you should back off the torsion bars when ever you remove the crossmember (remove the trans).
Here are some pictures of the modifications that I made to fit my 42 RH in.
If you want other tips not related to the crossmember send me a PM.
If you are successful, you will LOVE the Overdrive. With 3.23 gears my Dart does 75 mph at about 2000 rpms with the lock-up engaged. I'm thinking of 3.55 gears to take better advantage of the OD, and of course 1st and 2nd are both lower (numerically higher) than your old 904.
I installed a 42 RH in my 1970 Dart 2 years ago and have driven the car 13,500 miles so far. I have a few suggestions from my experience.
It's not just the shape of the crossmember that is important, it is also how heavy the material used is. The USCT crossmember (which must be modified to use with any A500 trans) is REALLY HEAVY. This seemed odd to me. I had the help of a fabricator/race car builder friend and he knew why right away. To have the trans correctly located it is necessary to cut out the hoop of crossmember that follows the trans hump out. You can leave a bit of it in place and insert a heavy band and weld it all up, but it is never going to be as strong as what you cut out. You have to also remove material near where the cross member bolts are and as shown in post #38 move the drivers side inner bolt outward, along with the bolt tube in the frame, to clear the bulge in the side of the A500. This is a BIG DEAL because the torsion bars put serious strain on the overall frame member that tries to tear things out downward in the middle. If you don't get this right, over time it will distort the whole frame member side to side. My friend has built a few C-body wagon race cars and they don't even have a loop over the trans tunnel. Instead they have a really beefy transmission cross member that is seriously attaches to the frame members that carry the torsion bars - that is why you have to take the tension off the torsion bars in a C-body before you remove the crossmember. If you do not, if you let the car sit for awhile, when you go to put the crossmember back in you will find the the torsion bars have bent the frame down in the middle. Although I have not confirmed this with USCT, I believe that this is why their cross members are such heavy material, and why you should back off the torsion bars when ever you remove the crossmember (remove the trans).
Here are some pictures of the modifications that I made to fit my 42 RH in.
If you want other tips not related to the crossmember send me a PM.
If you are successful, you will LOVE the Overdrive. With 3.23 gears my Dart does 75 mph at about 2000 rpms with the lock-up engaged. I'm thinking of 3.55 gears to take better advantage of the OD, and of course 1st and 2nd are both lower (numerically higher) than your old 904.