george88gta

iTrader: (3)

I am finally getting to stuff an LQ-4 in to my 1955 Chevy convertible. I am using the Street and Performance side plates and their biscuit motor mounts. Worked well. The tranny is a 200-4r and I purchased a C&P cross member that is designed for the convertible and a T350. Doesnt work. The pad area of the cross member hits the tranny oil pan and it doesnt line up with the rear tranny support. I checked with C&P and they dont have an alternative. Also, Danchuk and others use the C&P product. Any ideas? Worst case, I will have to build my own, but I really would like a quality aftermarket design so I can finalize the motor mount install and ensure everything lines up.

Cop Car

iTrader: (14)

sure you dont have it on backwards/upside down? it may sound stupid but you can sometimes think you have a piece on right and its not

george88gta

iTrader: (3)

I wish it was something as simple as that. This car has the "X" frame design and the new cross member only fits in one way. The ends of the cross member are angled to fit the "X" frame and the bolt holes have to be at the bottom inside edge. Without having done any research yet, it looks as if the tranny rear mount is located farther back on a 200-4r than it is on a TH350. The oil pan on the 200 is much longer and I believe that this moves the tranny mount farther back on the tailshaft. One thing I will look at is to see if cutting the pad off the cross member and relocating it to the back side of the cross member will align things. Dont want to destroy a $70 cross member unnecessarily.

mullenh

iTrader: (1)

there are business that make them. check bmr and also another company in georgia with a similar name i can not remember right now. if you check some of the post you will find them. The problem I have though is just like the above post because if you have the correct brace for that trans mission the pad area will match up. The pad is always the same for the transmission. They change the brace arm shape and length for the individual car but not the pad.

on my car we had to modify the arm length and height of the mounting position because of changes we made to the engine position and height.

G-Body

iTrader: (4)

I do not remember the exact dimension, but the TH200R4 has the mount located further back than the TH350. You will either have to make a new crossmember or find one that will fit. Does anyone make a TH400 crossmember for your car? The TH400 trans would be a lot closer to fitting and possibly a bolt in.
Go here and pull down about 1/4 of the page to see the dimensions http://www.rowand.net/Shop/Tech/Auto...issionSwap.htm

george88gta

iTrader: (3)

I checked the website ( thanks) and found that there is about 6 inches difference in the rear mount location. I sent a note to Classic Chevy, they offer a rear cross member for a TH400 in a convertible. They also sell the motor mounts I used so hopefully they will be able to verify fit before I place an order. Have to wait and see.

mullenh

iTrader: (1)

i thought a 400 and 200 were the same except for gear ratio

george88gta

iTrader: (3)

They are similar in size, but the 200-4r is an overdrive ( 4 gear) transmission and the th400 is a non-overdrive (3 gear) transmission. I believe that the th400 was the tranny that was installed by GM for the high performance big block applications.

bczee

iTrader: (12)

The TH400 is what the 4L60 is based on and then upgraded again to the 4l60e version. The 200r4 is somewhat smaller in size as compared to the TH400/4L60(e), it is more closer in size to the TH350.

The 200r4 needs to be built up in order to handle large amount of power. Standard 200r4 can not handle much power (except if they are the Turbo Buick ones) without breaking. Many of the aftermarket Trans built have some good built up packages and only need the correct Cable and a 12v+ source (and switch).

One plus is that the 200r4 is much lighter in weigth as compared to the TH400 / 4L60(e)'s.

You might look into some of the chevelle aftermark/remakes as they do market 200r4 crossmembers, maybe looking at one of those x-members might help out to see what is needed to fab or mod your x-member.

G-Body

iTrader: (4)

Looks like a review of GM transmissions is in order

Powerglide - the early GM 2 speed

TH350 - light to medium duty 3 speed

TH400 - Heavy duty 3 speed

TH200 designed in the 70`s as a lighter replacement for the TH350 for use with 4 and 6cyl engines (3 speed).

200R4 a redesign of the TH200 to make it stronger and add an overdrive (4 speed)

700R4 a clean sheet design, not related to any of the older stuff, overdive 4 speed meant to be stronger than the 200R4.

4L60 same as a 700R4, the name (designation) was just changed.

4L60E same as a 700R4/4L60E, but it is electronically controlled.

4L80E A redesign of the TH400, but it is electonically controlled, and has an ovrdrive (4 speed).