Hi guys, I've been thinking about dropping an LS1 and T56 in my '74 Vette and have been doing a lot of reading on the topic. I have been following the threads on the topic and gathered lots of information on the swap. My question is on the Transmission crossmember modififcation for the T56. My Vette is a 4speed car, so the crossmember is not removable. Can the people here with factory 4 speed cars, and now with T56s post pics of their mods to the Xmember and a minor explanation of what they did? I would like to modify my stock cross member, but suggestions are welcomed.

Thank you.

 

Nobody here with info on the crossmember modifications?

 

Bumping this for you. I'm going with a T56 also, but my car started life as an auto with the removeable crossmember.

 

I have modified mine over the years a few times. First one was for the TKO trans. I made it removeable but did not need to modify the mount as the kit came with the correct bracket. Then 2 years ago I did the T56 behind a Gen 1 SB and had to heavily mod the center as the mount was pushed back quite far. Currently I had to modify it again as I am putting in an LS3 which moved the mount forward 1.5 inches. So it is kind of ugly looking but is stronger than it ever was right now. No current picture but I can get one if needed.

 

Can you please post a picture of the modification for the T56 and the LSX engine. I'm really thinking of going forward with the swap, but am a bit skeptical on the modification to the crossmember.

Anybody else done this mod here?

 

In your other L98 heads thread you were saying that upgrading heads was over your budget and were questioning if a 4.100 gasket bore works on a stock bore. Changing to a LS/T56 combo will set you back thousands, probably over $10,000 to do it right and is a massive undertaking that will take many months and a lot of fabrication. Sounds like you have a Nissan 300 as a daily driver and the vette as a toy. Before you sell the ZX and redo the vette with the LS/T56 combo I would consider a couple things.

1. What will you drive in the meantime?
2. What are the real total costs? Can you afford it?
3. How much time will it take and do you have the time?
4. How much fabrication skills, mechanical knowledge and tools do I have to do this.
5. Do I have the space to do this that I can tie up for months?
6. Is it cost effective long term?
7. There are thousands of corvettes sitting in garages all over the country that are in the middle of a major upgrade that have been there 1, 3, 5, 10, 20, 30 years because some of the above items were not taken into account.

I would save some money for a while and drive the car maybe upgrade the heads to a good aluminum 64 cc head. If you decide to do the project get the engine and trans, do all the fabrication you can ahead of time, have a precise list of parts needed and steps to take before you do anything, don't disassemble the car until everything is prepared and ready to put back in it.

 

Check out my swap still underway here.

http://forums.corvetteforum.com/c3-t...o-my-72-a.html

As 63 Mako said it is a huge undertaking and will cost thousands to do it right. There have been some budget swaps also but that was not my deal. I chose the more expensive route. I will see if I can dig up some pics of the crossmember and if not I'll take some.

 

I can fab up whatever I need. As for the electrical, I can modify the harness myself. I can deal with electrical myself. Overall, the swap would be more cost effective in the long run. I'm not thinking of any major upgrades to the ls, that can wait.

 

I'm not looking for a highly modified ls swap. The stock motor will do for me. The ls1 is a great power plant stock. I've messed with a couple of them myself.

 

Did you do a search on T56? There are a lot of threads that have information on crossmember modifications.



Rick B.

 

I'll add something here, all the above apply, and what ever you think your budget is going to be, X it by a minimum of 2. There are and will be so many things that will add to the cost. Like said above, gather all of you parts ahead of time and don't start the swap until you think you have every thing, even then you will still need lots more to complete the swap.

Like Gordonm, I am close to finishing mine, and I decided I wasn't going to let the cost dictate the build, I wanted to make sure I had no regrets when I have it up and running.

Riggs.

 

By the way, If you have welding skills, the cross member won't be a problem to modify. By cutting the cross member out, a couple of inches away from the sides of the frame, and shortening the cross member .5 in on each side, then welding .25 steel plate to each side of the cross member and also on the sections of the cross member that were left on the car, you could now bolt through the new steel plates, making this a removable cross member. Before you weld the steel plates in, move the cross member forward or back wards into the location you desire, then clamp and weld the plates to the cross member. You would want to drill and bolt your plates together before you welded them into the car, this way the cross member is bolted to the transmission, with a jack to support the Trans, clamp every thing into place, then tack weld and check for fit, finish welding when happy with the fit.



I hope this made sense, I feel like I was rambling a little.

Riggs.