4 + 3 Transmission question??
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4 + 3 Transmission question??
I guess my question, at the most basic, is just what is the weak point of the 4 + 3 trans system, and how strong is it when NOT in overdrive??
I am going to fulfill a lifelong dream and put a big block in my '87 Vette. The first thing everyone says is "Say goodbye to the trans!!"
Now, the 4 + 3 is based on the Borg Warner Super T-10, and I have a ton of experience racing with them. Truly, despite some incredible abuse, I never broke one, and I've had them in numerous hot rods and race cars.
Way back then, if we wanted overdrive, and could afford it, the answer was a "Hone-O-drive", which mated either to the back of a T-10, or the front of a Ford 9" rear end. The consensus was that those setups were nearly as strong as stock when in direct drive. The key was to not do drag type launches when in overdrive.
Is this more or less the way of it with a 4 + 3??
Also, what IS the weak/failure point when they do "leave the chat"??
Thanks!
Vettepilot
I am going to fulfill a lifelong dream and put a big block in my '87 Vette. The first thing everyone says is "Say goodbye to the trans!!"
Now, the 4 + 3 is based on the Borg Warner Super T-10, and I have a ton of experience racing with them. Truly, despite some incredible abuse, I never broke one, and I've had them in numerous hot rods and race cars.
Way back then, if we wanted overdrive, and could afford it, the answer was a "Hone-O-drive", which mated either to the back of a T-10, or the front of a Ford 9" rear end. The consensus was that those setups were nearly as strong as stock when in direct drive. The key was to not do drag type launches when in overdrive.
Is this more or less the way of it with a 4 + 3??
Also, what IS the weak/failure point when they do "leave the chat"??
Thanks!
Vettepilot
Melting Slicks
Joined: Aug 2003
Posts: 3,438
Likes: 420
From: Lakeville MI
Mine has held up well with nearly 500 lb.ft and 500 whp. The Dana 44, half-shafts and u-joints not so much. I think this is the bigger concern depending upon tire choice.
Just be sure not to switch the od off (with manual control) over 170 mph (mechanical over-rev).
Gearing chart: https://www.andysautosport.com/learn...ors/#GearRatio
Just be sure not to switch the od off (with manual control) over 170 mph (mechanical over-rev).
Gearing chart: https://www.andysautosport.com/learn...ors/#GearRatio
Last edited by tequilaboy; Mar 8, 2025 at 12:08 PM.
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Joined: Jul 2010
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Ooohh... good point. I can't remember if it takes power to engage the overdrive, or to disengage it.
A sudden malfunction that causes the overdrive to disengage at speed would be a nasty surprise.
Spoken by someone who once speed shifted from 2nd back into first at 7000 rpms...
This problem though, would likely cause a high speed spin besides toasting the engine. All before you could say "WTF??!!" and get the clutch in!!
:~(
Vettepilot
A sudden malfunction that causes the overdrive to disengage at speed would be a nasty surprise.
Spoken by someone who once speed shifted from 2nd back into first at 7000 rpms...
This problem though, would likely cause a high speed spin besides toasting the engine. All before you could say "WTF??!!" and get the clutch in!!
:~(
Vettepilot
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Joined: Jul 2010
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Regarding the rest of the driveline... I am not going to do standing starts, and with original tires and nailing it while rolling I think it will break them loose before something else lets go....
???
Vettepilot
???
Vettepilot
