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post #1 of 3 (permalink) Old 01-07-2015, 07:37 AM Thread Starter
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Please Help an old man , Ha Everyone need your help thinking about putting a T56 in my 66 GTO that has a 455 in it putting out around 400 hp. I am new at this and have no clue what Iam doing . I need a list of what I need to make this work , can it be done and is it a good idea Some say The T5 but my research tells me they cant handle the hp. ?

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post #2 of 3 (permalink) Old 01-07-2015, 11:47 AM
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Many threads on this but here's my personal opinion......T-56 is 100 pounds heavier than a TKO 5 speed and why does anyone need two overdrives? Along with being heavier it is also physically larger and bulkier and needs even more floor pan alterations than a 5 speed.

Now, I said TKO because that is what I have and have experience with installing. I have heard that there are other options for 5 speeds out there that can withstand the power of a Pontiac V8 and do not need floor pan surgery but I have no experience with those.

Another option that is way cheaper is just run a more "highway friendly" rear axle gear.

Personally I like to have my cake and eat it too and the 5 speed fits the bill nicely. I would guestimate a complete setup with bellhousing, clutch assy and trans to be in the $3000+ range.
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post #3 of 3 (permalink) Old 01-07-2015, 01:02 PM
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T-5 for sure. Here's a link to start. Silver Sport Transmissions - Home

There are a slew of videos on the net as well.
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  Pontiac GTO Forum > The 1964-1974 Pontiac Tempest, Lemans & GTO > 1964-1974 Tempest, Lemans & GTO Undercarriage, Frame, Transmission and Differential Discussions.

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