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T56 Crossmember Demensions


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Dose anyone have the demensions for a t56 from a LT1 cross member in a 260z? Ive searched and found a few write ups with pics witch help a little bit but, none have demensions posted up. JTR never replied to the emails i sent last week so there no help so far either.

 

Thanks

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sorry no dimensions, however.......

 

I think it was easier just to make my own mount using 1/4" thick x 2 inch wide plate steel.

 

Just install the transmission were you want it then build a mount around the trans tunnel and trans mount. really easy.

 

The mount I made was straight across at the mount then had a little 1.5" upward offset for exhaust clearance then angled up on the ends to match the trans tunnel. The mounting bolts (2 on each side) are in the vertical section of the trans tunnel above the transmission mount. It fits perfectly since I tack-welded everything in place under the car. And is about 1/3 the size of the JTR mount.

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I researched this heavily and decidecd on this mount as being the best one and plenty strong enough and added stiffness to the body as well by being welded to the frame rails and floor pan. It bolts and unbolts very easily, I have had the engine and trans in and out twice and this mount was the best choice I made.

I forgot where on this site I got the info from but I am posting the plans and the original pictures that I kept. You might have to do a little grinding to mate the floor pan perfectly as there are some variations between the 280-260-240 floor pans. Just adjust the drawing for your actual distance between the frame rails, I had reinforced Baddog frame rails so my were actually shorter.

I will take some pics of my install if you want more pics, but it looks basically the same, I used the Poly trans mount for the T56 as well.

It leaves plenty of room for your dual exhaust as well, Although I ended up going with side pipes as I love the old school look.

Hope this helps.

Thanks,

Greg

280Z_T56_XMEMBER.pdf

13503_thumb.attach

xm2_thumb.jpg

XMEM_IN_thumb.jpg

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gvincent: I fabbed one of these and it appears that items 7,8,9 can be rectangular. I made it for my 240Z but have yet to install the V8 still being built. I intend to purchase one of the rear Bad Dog frame rails as a pattern to make my own from 2x3" tubing. Then attach the T56 crossmember to the 2x3 subframe rails that replace the originals.
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gvincent: I fabbed one of these and it appears that items 7,8,9 can be rectangular. I made it for my 240Z but have yet to install the V8 still being built. I intend to purchase one of the rear Bad Dog frame rails as a pattern to make my own from 2x3" tubing. Then attach the T56 crossmember to the 2x3 subframe rails that replace the originals.

 

Item 7 is just a flat plate for bolting up the drivers side of the removeable mount, Items 8 & 9 do the same for the passenger side, although we had to play with the angle a little to get it to match the tunnel angle.

 

I thought about cutting up the stock firebird T56 crossmember but it would of been a bitch to get any type of exhaust pipe through there, although I ended up not needing all that nice clearance this mount gives you, but iI can if I want to run duals out the rear someday instead of my sidepipes

Greg

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I used the standard JTR mount. Fit great!

 

They probably are and a lot of people on this site have used them, I am just a little uncomfortable bolting anything through the thin floor sheetmetal that wants to twist as the motor and transmission do.

Greg

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  • 1 month later...

The JTR mount will not work in a 280z as the area on the floor to which it should mount is not flat at all. I bought one and JTR has offered no further information so far on why it will not fit. I am either going to buy the JCI member or fab my own? I like the one shown above.

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The JTR mount will not work in a 280z as the area on the floor to which it should mount is not flat at all. I bought one and JTR has offered no further information so far on why it will not fit. ...

 

Hmm...?

I don't know what issues you ran into. I did this swap a few years back for a friend: '95 LT1/T56 into a '78 280. I used the JTR kit. If memory serves me I think I had to cut about 1/2 inch off one end and re-drill the hole for the tranny mount. That's about it. However, the 3 pound sledge was nearby as it is required to clearance the tunnel. I might have delived a few "adjustment" blows to the floor but, honestly, I can't remember.

 

I made backer plates for the inside out of 1/8" steel and bolted it up. He's driven it hard for the last 4 or 5 years and the only thing that has fallen off is a wire on a fan relay. Tranny is still there though.

 

As far as driveshaft u-joint angles, every car is different. After doing two of these swaps (first was a tpi/T5) I have found that the JTR tranny mount combined with the RT diff mount, and a few flat washers, make adjusting the u-joint angles fairly easy. I could never get the nose of the diff low enough with the stock front diff mount.

 

One other item: the floor of a 280 is thicker steel than a 240. Lots of guys have used the JTR mount in 240's without incident, me included. Unless you plan on using a solid mount and forced induction, you shouldn't have a worry on the floor failing.

 

If you are using solid mounts and forced induction you are familier with failures anyway.:burnout:

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