Bigblock project
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2nd Gear
Joined: Apr 2010
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Bigblock project
In search of information on converting a 1968 327 4speed to a 454 with an automatic. I am thinking either the 700r4 or 200r4 tranny. Does anyone know any real performance differences in those trannys? Also does anyone have any tips or secrets to make this conversion easy? Any information on this would be greatly appreciated.
Last edited by j5man; Apr 10, 2010 at 12:31 PM.
Pro
Joined: Mar 2002
Posts: 511
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From: St. Louis MO
Check out bowtieoverdrives.com or transmissioncenter.net
I don't know how much power you plan on making from the 454 but your going to need at least a level 3 from either place. Something that can handle 600 ftlbs of torque just to garantee longevity. I don't know that the 2004r can handle a big block. I haven't really looked at speed parts for the 200 in a while. I have a 700 behind my big block and it works great. The overdrive is a nice touch.
Personally though I wish I would have sprung for the manual when I was buiding my car. There's a lot of nice 5 and 6 speed options for these cars now.
Bow Tie Overdrives sells all the stuff you need to convert to an automatic, give them a call and they will set you up. You will need to find a shifter if you want to stick with the factory style or by something from B&M or TCI.
Art Carr sells a nice transmission too, but they are a little more expensive.
As for the big block dropping in all you have to do is transfer the engine mounts from the small block to the big block. Accessories will be a bit of a challenge depending on what you plan to use.
Good luck.
I don't know how much power you plan on making from the 454 but your going to need at least a level 3 from either place. Something that can handle 600 ftlbs of torque just to garantee longevity. I don't know that the 2004r can handle a big block. I haven't really looked at speed parts for the 200 in a while. I have a 700 behind my big block and it works great. The overdrive is a nice touch.
Personally though I wish I would have sprung for the manual when I was buiding my car. There's a lot of nice 5 and 6 speed options for these cars now.
Bow Tie Overdrives sells all the stuff you need to convert to an automatic, give them a call and they will set you up. You will need to find a shifter if you want to stick with the factory style or by something from B&M or TCI.
Art Carr sells a nice transmission too, but they are a little more expensive.
As for the big block dropping in all you have to do is transfer the engine mounts from the small block to the big block. Accessories will be a bit of a challenge depending on what you plan to use.
Good luck.
Le Mans Master
Joined: May 2006
Posts: 9,993
Likes: 1,136
From: League City Tx
My SB to BB conversion thread....
http://forums.corvetteforum.com/c3-t...on-begins.html
As for the 200 vs 700...... No comparison.... 200R4 all the way. Better gear spacing, can be built to handle 800hp, less parasitic power loss, easily bolts right in and can use a stock Th400 tranny crossmember and driveshaft(with a yoke change)..... I really wanted to go to a 200R4 myself but....my engine builder convinced me to stay Th400..... Someday I may go 200 anyway though....its just $$$ to build a strong one...
http://forums.corvetteforum.com/c3-t...on-begins.html
As for the 200 vs 700...... No comparison.... 200R4 all the way. Better gear spacing, can be built to handle 800hp, less parasitic power loss, easily bolts right in and can use a stock Th400 tranny crossmember and driveshaft(with a yoke change)..... I really wanted to go to a 200R4 myself but....my engine builder convinced me to stay Th400..... Someday I may go 200 anyway though....its just $$$ to build a strong one...
Le Mans Master
Joined: Apr 2007
Posts: 7,353
Likes: 72
From: Graceland in a Not Correctly Restored Stingray
The BB I can understand, but having ditched an auto in favor of a manual, I can't see the trans swap. Yes, preferences vary, but your manual frame didn't come with a removable trans x-member, so there's also that issue... My $02
Le Mans Master
Joined: May 2006
Posts: 9,993
Likes: 1,136
From: League City Tx
Youre gonna spend a minimum of $2k for either one and thats just a decent street tranny good to maybe 500hp.... No reason at all to use a 700R4.....its way longer, you will need a different crossmember(which you will anyway since you have a 4spd) but......The 200R4 goes right in, its the same length as a T400.....The 200r4s are way stronger when built up...700hp 200R4s are no problem. The 200s use less power, don't have the weak *** 4th gear band issues the 700s have....hands down a better tranny...Have a nice stall converter built and use the lock up function....Good mpgs on the freeway and a viscous launch......go spank those stick cars....
