I think I will be able to modify the original trans mount to hold the trans at the proper angle. I went by a friend's house to look for a spare tranny mount so I don't have to cut up my original, but he didn't have the right one. I want to keep my original so I can still go back to a 4-speed if I choose to.
I will try to fabricate a rod to hook it up factory style first. Right now, I welded up a little bracket to hold it at the proper angle. This is a temporary bracket. You will have to build a new lower trans mount. There is a picture of one on THETRANSMISSIONCENTER's website.
That speedo might be a real problem, but Terry (tactransman) says it'll clear if the trans and engine are pushed rearward before tightening the bolts.
I'm going to go for it before I replace my entire floor. I'm going to solve the Slap-Stik problem. I'm cutting out my floor and might go with a 4-speed so I thought I would try to fit the 518 before the rest is cut to document what is needed to make it work. This way, our site members can see how I did it.
I included a picture of the slap-stik linkage for the 518 project. The part that the others are having problems with is this vertical bar. When the new fatter 518 case is installed, It's width takes up this space where the bar is. I don't see it as a problem.
After pulling the 904,
I modded the 518 case. This has to be done to clear the stock trans crossmember, I used a cutoff disk to remove it. Another small section has to be removed to clear the shifter rod, pictured farther down.
I then installed it for mock up. I used a bubble level on the a/c compressor's flat spot to know when it was back at it's original height. The 518 is huge compared to the 904. After getting it installed, I noticed that the speedometer plate, where the speedo plugs in, will be too close to the crossmember. Jacksboy's thread on Moparts with another user that installed one says to push the engine all the back in it's mounts then the speedo will plug in. Another possible fix would be a new GPS speedometer which just came out. I'll work on the shifter linkage later but it looks like I'll have to be very creative since the hole is now blocked by the trans.
Looks like a little bending of the upper pivot and fabricating a lower mount might just work. All of the ratios work because you are using the stock linkage and arms. The arm has to be in the tunnel before you install the trans. The trans needs a slight mod by cutting off a little piece that's in the way. The rod at the trans could be straightened out and shortened if needed. It seems to work. I don't have headers for the mock-up though. I still need to fab up a lower mount.
More pics after I make it.
Okay, It's done. It shifts perfect because it is using the stock arm.
When I bought the junk yard 518,
I took the little bracket in the pic with it.
I cut it at the bend, cut it to length,
then welded it back together to hold the bottom of the rod.
I bent the bracket a little to hold the rod at a 90 degree angle.
I haven't decided to keep the 518 or convert it to a 4 speed yet, but I now know it can be done. The speedometer nut can be mated up by grinding the corner a little.
