Team Camaro Tech banner
Cancel
Create thread New Garage Forums

700R4 and Turbo 400 cross member?

Jump to Latest
1 - 20 of 20 Posts
J

Joe Harrison

· Registered
Joined
·
7,361 Posts
Discussion starter · #1 ·
I finally dug up a 1986 700R4 core transmission to have built. It came my way for the super low price of …here take it…. it’s yours!!!

I have done a search looking for turbo 400 cross member use. From what I found it seems most use the turbo 350 cross member with no modification or it needs to be cut out to enable pan removal.

I have seen very little use of a turbo 400 cross member. It looks like the sides of the area where the trans mount is installed needed to be trimmed down on the sides? I did not find anything specific to fit in this area.

It apears from my search that not many people are using a turbo 400 cross member because I could not find any definitive info on it, is there a reason it’s not used? I was looking at prices and you would think that at less than 1/2 the cost and from the limited info I was able to find that with just mild trimming that it can work or am I mistaken?

Please post any info or pictures you have on using one. I would like to know the area that does actually need to be trimmed. Would also like to know any draw backs to using the turbo 400 cross member.

I can always go with a bowtie overdrives cross member or some other specific made cross member, it just seems a little hard to justify the cost of them if the TH 400 will work with some mild modifications.
 
#3 ·
My mechanice used my old TH350 crossmember when I had the 700r installed. He modified it to access the pan bolts and it saved me buying something else :)

Image
 
Save
Reply Quote Like Like
Discussion starter · #4 ·
Looking at that, it tells me the Turbo 400 cross member would actaully move fwd 1.8 inches. It also looks like the mount holes are spaced farther apart at the trans a 400 being 4.5 inches while the 700 is 3.5 inches.

Does anyone know if the holes at the mount in the cross member are spaced out by the same amount of 4 inches? Or are they would I get lucky and ahve the same mounting dimention at the cross member?
 
Discussion starter · #6 ·
BPOS said:
I used the old PG/T350 mount on my 2004r with a t400 x fit was fine Be aware that the threaded holes for the mount in the 700 are likely metric
Click to expand...
Well I think I should be able to use the TH 400 Cross Member, still don't know if I need to trim the sides but if the mount bolts up I think it should work and I will also have pan clearance.

Now to talk to the local brick and mortar Camaro part guy and see if he will sell me one and take it back for store credit if not.
 
Discussion starter · #8 ·
BPOS said:
Try and get one for a Firebird. The Camaro T400 only came behind big blocks and has the pad mounted off-center.
Click to expand...
And there is the Ahh Haa moment!! :beers:

Thank you!!!
 
Discussion starter · #9 ·
#10 ·
The TH-400 mount VS. TH700r4 mount is approx. 5" difference. You will need to modify a TH-400 extensively. You will have to make the mount notched into the tube portion of the crossmember. How do I know this ? Mine is done that way. I wouldn't recommend doing it that way. After you notch out the tube you then have to plate it. (reinforce it)
 
owns 1969 Chevrolet Camaro
View garage
Save
Reply Quote Like Like
Discussion starter · #11 ·
TJS69 said:
The TH-400 mount VS. TH700r4 mount is approx. 5" difference. You will need to modify a TH-400 extensively. You will have to make the mount notched into the tube portion of the crossmember. How do I know this ? Mine is done that way. I wouldn't recommend doing it that way. After you notch out the tube you then have to plate it. (reinforce it)
Click to expand...
Do you have any pictures of this? I would like to see what your talking about. Having hard time understading what your talking about.

Are you saying the trans mount (rubber) is different?
 
Discussion starter · #13 ·
BPOS said:
I think he's saying that the 700r4 mount is 5" further to the rear than the t400 mount. This doesn't jive with the info on the TCI link, but he's actually done it so the TCI info could be incorrect.
Click to expand...
That was my thought also but then the mount and tube modification threw me off. I think he is saying the trans mount hits the tube or is it the trans tail shft that might hit the tube?
 
#14 ·
OK - reread his post and paid closer attention

Looks like the 700 mount location is forward of the t400 mount location, not rearward. In which case the mount pad on the t400 xmember is cut off, and the tubular part of the xmember is modified to accept the rubber mount.

So you need to decide whether you want to buy, cut and modify a t400 crossmember, buy a BTO crossmember for $175, or modify your existing t350 crossmember like click showed. I'd be inclined to use the t350 cross since you already have it which would make the price roughly $0.
 
#15 ·
Al is correct. The mount is 5" forward of the TH-400. The TH -400 crossmember is mounted with the tab to the rear. If you measure forward 5" you are in the middle of the crossmember tube. I don't think I have any photo's of this and car is put away for the winter. I'll see what I can do.
 
owns 1969 Chevrolet Camaro
View garage
Save
Reply Quote Like Like
Discussion starter · #16 ·
Gotta love this place....community thought process....I get it now.

When it comes to the cost I am a cheap azz. No offence to click, that would work for me but I need a cleaner looking install. So I guess I need to budget for a crossmember....which kinda sucks. Looks like I need to save up a little longer to do my conversion. At least I am ahead on the core.....will find out more about some of the hard parts when it gets torn down. I just hope the usable stuff is good....LOL!!!
 
#17 ·
Here are a couple of pictures that I just took while lying on a COLD cement floor and sticking the camera under the car.





The new mounting pad has to be notched into the front of the crossmember.

Here is also a picture comparing the TH-400 big block crossmember and the firebird piece.

 
owns 1969 Chevrolet Camaro
View garage
Save
Reply Quote Like Like
1 - 20 of 20 Posts
About this Discussion
19 Replies
6 Participants
Last post:
Joe Harrison
Team Camaro Tech
posts
2.4M
members
90K
Since
1998
A forum community dedicated to 1st generation Chevy Camaros owners and enthusiasts. Come join the discussion about performance, builds, restoration, modifications, classifieds, troubleshooting, reviews, and more!
Full Forum Listing
Explore Our Forums
Bench Racing Engine Body Shop Performance Brakes, Suspension & Steering