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Down right shift pattern. Identification

396 Views 15 Replies 6 Participants Last post by  Injuneer
Hi all.
First post here. But I was looking at my neighbors 74 firebird for sale. He doesn't know much about it because it was a project car from a relative .(I know. Typical story) It has a 350SBC

It has a down lower right reverse 4 speed shift pattern. Some research leads me to believe it could be a truck transmission like sm465 , because the throws do feel kind of long. It also needs a lot of clutch just to get the car moving. Like it has no power down low. I wasn't sure if it was a timing issue or perhaps someone regeared the rear-end drastically juat to work with the 6.55 first gear if it was indeed a sm465

First gear doesn't seem to run out of speed/gear too soon , and 4th seems to cruise around 60mph no problem. It just needs a lot of throttle and clutch to get it moving in 1st. Other than that it seems to drive fine. Except sometimes when I accelerate it feels like a bowling ball in the trunk just rolled and slammed into the left side of the car , with a bang. I'm thinking thats not related to this transmission but Maybe just a bad axle or wheel bearing. Or diff perhaps.

Any one have any ideas of whats in this car before I start bothering him to tear around his car again?

I have attached a picture of the shifter. It is round and straight and comes out of the floor on the correct location.

I am a little worried buying this from him as a project because I don't know how much "custom" work was done to get this odd transmission in there. And if it'd turn into a money pit just to drop a muncie back in.

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Wow! Never heard of the SM465 (SM = Saginaw Michigan), had to look it up. Yes 😵‍💫 , it really has a stump pulling 6.55:1 1st gear. And from the looks of it, with option for two different power takeoffs, it's probably a real “boat anchor”. What rear axle gears do you think it has?

I don't think all the T5’s have a synchro in reverse. See this article, scroll down to paragraph under 7th photo (not counting the header photo at the very top):

Also read the paragraph below the 8th photo for an explanation of why the T5 reverse does not have a synchro, while the T56 does have a reverse synchro (and a reverse lockout).
This site has a good thread on the T5, including detailed lists if part #’s for various applications (e.g. post #6). Also a lot of posts debating the gear oil vs. ATF vs motor oil (there are apparently some shop manuals out there that recommend motor oil, because that's what GM used to achieve a higher fuel economy number).

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