major 700r4 conversion problems - need help
Thread Starter
Instructor
Joined: Jan 2003
Posts: 143
Likes: 0
From: Vancouver Wa
major 700r4 conversion problems - need help
I am in the process of converting my 81 over to built 700r4, thought I had everything I needed but I guess I was wrong, this takes an 82 crossmember right? Does this crossmember bolt where the old one went or do I have to make new frame holes? The local vette shop is not sure what crossmembers they have so far none of them work??????
I also bought a drive shaft from them to be shortened to 25 inches only to find out that it is to wide to fit in the yokes so that is a waste
And the linkage bracket doesn't fit below the tranny pan as the bolt spacing is different between the two trannies?????
Help on this much appreciated as I have to bum rides until it is together
I also bought a drive shaft from them to be shortened to 25 inches only to find out that it is to wide to fit in the yokes so that is a waste
And the linkage bracket doesn't fit below the tranny pan as the bolt spacing is different between the two trannies?????
Help on this much appreciated as I have to bum rides until it is together
Race Director
Joined: Apr 2007
Posts: 14,062
Likes: 602
From: Henderson Nv-Rohnert Park/Sonoma C o. ca/born in NY Rockaway Beach.
http://forums.corvetteforum.com/c3-t...00r4-swap.html
I just searched... 700r4 swap.... you get a ton of info...
I just searched... 700r4 swap.... you get a ton of info...
Race Director
Joined: Apr 2007
Posts: 14,062
Likes: 602
From: Henderson Nv-Rohnert Park/Sonoma C o. ca/born in NY Rockaway Beach.
Race Director
Joined: Sep 2004
Posts: 11,874
Likes: 263
From: Arlington Va Current ride 04 vert, previous vettes: 69 vert, 77 resto mod
I am in the process of converting my 81 over to built 700r4, thought I had everything I needed but I guess I was wrong, this takes an 82 crossmember right? Does this crossmember bolt where the old one went or do I have to make new frame holes? The local vette shop is not sure what crossmembers they have so far none of them work??????
I also bought a drive shaft from them to be shortened to 25 inches only to find out that it is to wide to fit in the yokes so that is a waste
And the linkage bracket doesn't fit below the tranny pan as the bolt spacing is different between the two trannies?????
Help on this much appreciated as I have to bum rides until it is together
I also bought a drive shaft from them to be shortened to 25 inches only to find out that it is to wide to fit in the yokes so that is a waste
And the linkage bracket doesn't fit below the tranny pan as the bolt spacing is different between the two trannies?????
Help on this much appreciated as I have to bum rides until it is together
on my 77 i used the BTO crossmember and it used the original mounting holes, these holes are nothing special just tapped holes in the frame so making them is no big deal...
i was able to have my original drive shaft shortened. and when you do this take the yoke to the driveline shop so you can have them balanced./ most people dont cut the drive shaft unitl they get measuring directions from the drivline shop.
true the bracketry is different on the pan as well as the shift detent....the shift work kit comes with both the correct shift detent and the right bracket on the bottom. i actually made my own bracket for the bottom using the original one but then realized i had one in the shift works kit
these are reverse images( by accident)
tight fit
does not fit
Last edited by bobs77vet; May 30, 2011 at 12:27 PM.
Team Owner
Joined: Jan 2006
Posts: 37,637
Likes: 3,112
From: Crossville TN
I'm planning the same changover, from a TH400 to a 700R4. I think you can still use the original crossmember, but you will have to make a bracket to mount to the exising crossmember and provide a new location for the rear tranny mount. It will also have to have the E-brake pulley relocated (cut off and rewelded) so that there is no interference with that mechanism and the new tranny. You just need to measure the differences between your present tranny mount holes, etc. and those of the new transmission so that whoever does the work (I know of a very competent welder in my area) knows what to do. Doing so can save you a lot of money on expensive aftermarket pieces.
P.S. You also want to check out any need to relocate (widen) the position of the exhaust pipe(s) so they adequately clear the trans oil pan to limit interference and/or excessive heat.
P.S. You also want to check out any need to relocate (widen) the position of the exhaust pipe(s) so they adequately clear the trans oil pan to limit interference and/or excessive heat.
Race Director
Joined: Sep 2004
Posts: 11,874
Likes: 263
From: Arlington Va Current ride 04 vert, previous vettes: 69 vert, 77 resto mod
before you pay for labor of a welder price out the manufactured cross member....if its a buddy and its free then you cant beat that
Corvette Stories
The Best of Corvette for Corvette Enthusiasts
Grand Sport & Grand Sport X Launch Alongside All-New 535hp LS6 V8!
Michael S. Palmer
5 Reasons Bad Drivers Crash & 5 Ways to Avoid a Costly Mistake!
Joe Kucinski
7 Bolt-On Upgrades From Extreme Online Store to Level Up Your C6 Corvette
Pouria Savadkouei
How Likely Are These Five 2027 Corvette Rumors to Be True?
Brett Foote
9 Best Corvettes You Can Buy for Half Price (& 1 You Should NEVER Buy!)
Joe Kucinski
8 Very Best Corvettes of Amelia Island 2026
Joe Kucinski
Top 10 WORST Corvette Engineering Failures of All Time!
Joe Kucinski
10 Records the C8 Corvette Generation Has SMASHED (& 1 Glaring Failure)
Joe Kucinski
7 Wildest Corvette Concepts Ever Made
Brett Foote
Race Director
Joined: Sep 2004
Posts: 11,874
Likes: 263
From: Arlington Va Current ride 04 vert, previous vettes: 69 vert, 77 resto mod
you didnt mention your exhaust set up.....if its a true daul set up you will want to add and x or h pipe to it......if you have 3.08 rear end you will notice sometimes after letting up on the gas pedal the car will lock up at 40 mph at 900-1000 rpm and it will start to lug...(imagine coming off of a clover leaf entrance ramp and slowing down to merge) adding the H or X pipe makes this go way.....adding a speedometer controlled lock up will do this also, so will down shifting to 3rd, and so will a simple on/off toggle switch that unlocks the torque converter, i have an RPM switch that controls my lockup that a friend made and i also have the toggle switch.
