After getting the F-2 crossmember and seeing just what I would have to do to adapt it to the F-1 frame. I'm back to modifing the F-1 crossmember. I know there is 1000 was to skin a cat so lets see what ya have. <!-- / message --><!-- sig -->

 

no grinding rivets? lol. I got this pic from somewhere.

 

This picture was what I was hoping to do, but the T-19 is about 3 inch to long. Dick C sent me some info that has given me some new ideas.

 

OK. What you see here is a piece of 4x4 square tube cut and ground to shape and welded to an F1 crossmember. You can go with something like this to the length you want.

 

Havi, Yes this would be the ideal situation, but as you look at my photo the 13 inch mark on the tape is were the stock tranny length ends. You can see the extra length of the T-19, so it's not the tailhousing that's the problem it's the case.

 

Havi what transmission is that?

 

When installing the 500ci and TH400 in my 49 I opted to cut out the original x member and make my own...sort of.
I toyed with the idea of extending the original or making one from scratch. Bu then I tried the x member from my donor car. Wow, almost a perfect fit. I had to add 1/2" to each side of it and drill a couple holes in the frame but it was very minor.



Bobby

 

This one was posted on the old Bonus Built site a few year back, I consider it a work of art:

 

Now THAT is a beautiful piece of work! The craftsman that built that crossmember extension truly "gets it". The transmission crossmember in these trucks is a structural member as well as just an appendage to hold up the transmission. The original design attaches to both the top and bottom of the frame rails and holds them parallel as well as just tying them together. 90% of the crossmember mods that I've seen done to these trucks eliminates this critical function in the name of making transmission clearance. At that point, metal fatigue and frame rail cracking from the rails twisting is inevitable. It's not if but when - especially when it's done in the name of stuffing in a higher performance powertrain as is usually the case. A couple of the pics in the F-2 crossmember thread of the C4 behind a flatty make my skin crawl. After the center of the original crossmember was chopped out, there's nothing left at all between the front crossmember and the front bed crossmember to prevent the rails from twisting.

It really doesn't have to even be that complicated, though. The '80-'96 F-series trucks had a three piece tranny crossmember that performed the same function. The main crossmember was a C-shaped channel that could not flex or bend. It spanned the distance between the rails and bolted to the lower web on each side. Then there was a diagonal brace on either side that bolted to the top web of the rail and then met the main crossmember about 4" or so out from the rail to eliminate twist. I've got one of these around here and I'm going to try to shorten it and adapt it to my F-2. If it works OK, then i can blow out the rivets and completely remove the original except for a chunk on the left side to mount the pedals and master cylinder.

 

That is a piece of art... and not to far off from the one I just finished sketching. The center section that's getting cut out will be used again to pick-up the tailhousing. When welded back together it will have the same structural capacity as the original. I hope.

 

Thanks, that is my frame in those pics. Thanks for posting those as I can't yet.

I can only say the work is excellent because I did not do it myself but one of my friends who is very handy with metalwork...

You should see his own cars!

One thing we may have mis-measured though is the height because it seems that I need to make a bump to the floorpan for the trans adapter.

I have more pics of my project, I will post them as soon as I can.

Thanks.

 

Fin,

You friend is a true craftsman. Good to see you've joined the board. A lot was lost when the Bonus Built site went off line.

 

Finnflat, your welcome it was Bob who posted them first. Welcome to the forum, look forward to more pictures of your project.

 

Cutout the center section of the crossmember today. After the first cut was complete, I was surprised to see movement in the frame. Not sure if the right side of the frame twisted up or the left side dropped down. The total movement was less than 1/4 inch. There was definitly some stress in the frame. Other than that everything went pretty smooth. On another note the axle and tie rod are bent. More up-grades to be sure.

 

There's an old thread where someone warned that you need to brace the frame rails before cutting...

I think the best solution to the Bonus Built curse (that crossmember) is to replace the center part of the stock one with something that retains the strength of the stock c-member, but doesn't carry the trans mount at all. A separate c-member added behind it seems like a better solution. While Finn's c-member above is a beauty, the rearward offset to the mount puts a twist on the stock part of the c-member. I doubt it's a problem, just sayin'....