4+3 to 6 speed

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May 10, 2019 | 01:18 AM

Logan Shoemaker

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6th Gear

Joined: May 2019

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From: Tulsa, ok

4+3 to 6 speed

Hey guys. So I haven't seen anyone ask this yet but I'm sure it's been done countless times and I just dint know. But what will it take for me to take my 4+3 and have a good ol 6 speed in my c4?

May 10, 2019 | 01:48 AM

65Z01

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Joined: Dec 2000

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From: SE NY

Cruise-In II Veteran

SST makes a Tremec makes a 6-speed kit for C3, maybe they can give you a solid answer.

May 10, 2019 | 08:06 AM

ChumpVette

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Joined: Jun 2010

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A lot of work.

Biggest part is reglassing the tunnel as the 4+3 shifter is mounted to the trans tunnel.

May 10, 2019 | 08:50 AM

slow_zo6

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Joined: Mar 2018

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From: WV

Quote:

Originally Posted by 65Z01

SST makes a Tremec makes a 6-speed kit for C3, maybe they can give you a solid answer.

That they do but like the previous response-it def ain’t cheap😬

May 11, 2019 | 07:50 AM

hcbph

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Joined: Aug 2013

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From: Minneapolis Mn

Quote:

Originally Posted by ChumpVette

Biggest part is reglassing the tunnel as the 4+3 shifter is mounted to the trans tunnel.

I can't speak to a 6 speed, but you may want to check with some of the vendors (assuming you're considering new) to see if they have a direct fit transmission. The reason I say this is my 86 had a Tremec 5 speed put in it before I purchased it. I did have a chance to get under it when I bought it looking for a transmission model. While looking for those transmission numbers, I don't remember seeing any modifications to the transmission tunnel. The shifter in mine looks to be right where the original 4+3 would have been located.

If on the other hand you're looking at a ZF 6 speed, I have no idea on that one.