LT1 with TH400?
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TECH Resident
Joined: Jul 2009
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From: Bahrain
LT1 with TH400? I have the opportunity to pick up a TH400 in full working order for a very decent price (its a steal to be honest) and since my 4L60E is already clunking and clattering, I was thinking of installing this transmission instead of a rebuild that would cost me a lot more.
What changes would I need to make to my car to be able to swap it in?
With a dead opti, I might even finally make the jump to carb along with the transmission swap.
What stall would go well with my CC503?
What changes would I need to make to my car to be able to swap it in?
With a dead opti, I might even finally make the jump to carb along with the transmission swap.
What stall would go well with my CC503?
If you go to the transmissions section there is alot of info about it in the stickies and threads. I did the swap to a th350 and love it. I would go with no less than a 3600rpm stall but I guess it all depends on what you are doing with the car and what you consider tolerable for driving it will differ from person to person.
Do it and never look back!
you will need a bigger stall then you probably have, atleast a 4k and what gearing do you have already.
You will need a differ driveshaft, new crossmember with or with out a tq arm relocation bracket.
you will need a bigger stall then you probably have, atleast a 4k and what gearing do you have already.
You will need a differ driveshaft, new crossmember with or with out a tq arm relocation bracket.
with a cam as small as the cc503 i would not go with a huge converter, i wouldnt go no bigger 3200 at the biggest, plus i would not go with a th400 it will rob you of hp and tq, if you have to switch to a 3 speed go with a th350 trans
Hell no th400 all the way, build once not twice and for the steal do it. He will have to get a bigger stall due to the fact the gearing is different in the trans's. Yes you will lose a bit of hp,tq but thats the difference between stalls and rear gear as well.. Its for future referances of having the th400 already and then he can go bigger with cams later..
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Verdad Gallardo Thread Starter
TECH Resident
Joined: Jul 2009
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From: Bahrain
Well, wouldn't it be the same for an LT1 F-body because all the dimensions are going to be the same for the production line?
Yea you would think so but if the frame is tweaked alittle or something isnt lined up right the drive shaft would be alittle longer or shorter. Also with different rear ends the drive shaft would change from car to car. Its one of those things you will have to get custom made anyways so why not wait to measure and double check yourself you know. I agree with you though they should all be pretty much the same I am sure you read this but here it is anyways.
Driveshaft-
In most cases the stock driveshaft will need modified. You can buy an aftermarket DS from many vendors online. Or just take you stock one to a local DS shop with the measurments and they will cut it for you. Driveshaft lengths will vary from car to car depending on a couple factors. If the car is using a 12 bolt or a 9" you will see some variances. Also, if you are using different types of motor mounts compared to others (stock, solid, poly or motorplate). It is best to measure the driveshaft for your application.
TH350 with a 9'' tailshaft will work with the stock DS
see Dennys drive shaft for info on measuring
The swap is really easy if you have everything to do it. It will be even easier since you are already auto. I did it from M6 so I had to change out the pedals shifter run cooler lines all thats stuff and it was still pretty easy to do. Word of advice dont short change yourself on the stall speed like I did at first go big the first time and enjoy.
Launching!
Joined: Dec 2004
Posts: 284
Likes: 1
From: Hebron, Oh
I am looking to do this swap as well, tired of the six speed. I picked up a TH400 w/converter(stock) for cheap and in working order. Not sure when I will change over to the auto, I have had the trans for a few years now. I still need to buy everything else for the swap, but there are a few things that need addressed with the car before I swap the tranny.
Launching!
Joined: Dec 2004
Posts: 284
Likes: 1
From: Hebron, Oh
The 6 speed cross member will work with a spacer, I believe 1". There is a company that makes them. A tunnel mount torque arm must be used. For my swap, I still need a driveshaft, torque arm, converter, trans cooler, shifter, and get the parts for the electric speedo to work. It's a big list, and that is why it's on the back burner for now.
Yea pretty much the same as a A4 conversion just add pedals tranny cooler with lines flywheel and a plate to cover the hole where your stick shift is. If you use a TH350 with the 9" tailshaft the stock drive shaft will work. I imagine it might drop acouple pounds also going from M6 to TH350. I am going to have to research that.
I kick myself in the Butt now for not weighing it when I had everything out. I know the M6 seemed heavier than the TH350 but who knows. Plus the TH350 is so much easier to rebuild if it should ever go out I imagine the TH400 wouldnt be much harder. Theres almost nothing to it and parts are pretty cheap for it.