Thread: Need Chevy Guys Help On Tranny Id

Tweet

I bought this 3 speed trans on Ebay to use in the el cheapo '23 T bucket. I intend on putting it behind the 5.7 Vortec I've got. I know the ratio selection isn't like a 4 or 5 speed, nor is the strength, but it is perfect for the '50 style rod I want to build, and I got it cheap, like $ 29.00, with brand new Hurst shifter. (ok, so shipping DID cost $ 90.00, but still not too bad)

Here is the problem. I haven't played with Chevy's in lots of years, so I don't know what this trans is. It was advertised as '64 to '67 Chevy Nova, and that is about it. I took some pictures tonight to post, thinking some of you could ID it for me. Here are the numbers and dimensions I get from it"

Case has a number that looks like 3748368, plus GM 74, and Ll271 also. The numbers could be different, as they are stamped and the 8.s look like 3's and so do the 6's.

The overall length from the flat surface where it bolts to the bellhousing and back to the end of the tailshaft is 21 inches. The tailshaft itself is 14 inches, so the main case is only 7 inches.

The round part of the snout that goes in the bellhousing hole is 4 1/4 inches, and the tip of the input shaft that goes into the pilot bearing is 5/8 inches.

The bolt holes where you bolt it to the bellhousing are 8 1/4 apart on the top two holes, and 9 1/4 apart on the bottom two. The top and bottom holes are 4 3/4 inches apart. It has 10 splines on the clutch portion of the input shaft.

I know this is probably a weak 6 cyl trans, but if it bolts up to a v8, that is all I need it to do. This will be a mild street rod, so hi performance is not important.

Any help you guys can give will be appreciated, and I am truly sorry about the hundreds of posts I have put on here bashing Chevy's. KIDDING, I'M JUST KIDDING.


Don

Got so caught up in my joke I forgot to post pix, here they are.


DON

Pops, are you sure about your dimensions? The top hole spacing at 8 1/4 seems right, the bottoms should be 9 even. The bellhousing flange should be 4 1/2. If it works out that way, any stick shift bell housing will work.

It could be, Bob. I just did a quick measurement, so I could have screwed up.

Is there any website where I can cross that part number on the case?

Don

Also, if I can ask for some additional info...........I see flywheels that are 153 tooth, some 168 tooth, some internally balanced and some externally balanced.
QUestion, is a 99 Vortec 350 internal or external balance, and what tooth flywheel is for these? The engine only had a marine flywheel on it, so I have to dig up all the stuff I need to make it automotive.

Thanks,

Don

Thanks Denny, it does. So do I read that if the engine has a one piece rear seal it is externally balanced? and has a 168 tooth flywheel? or am I reading that wrong?

Don

Originally Posted by Itoldyouso

Thanks Denny, it does. So do I read that if the engine has a one piece rear seal it is externally balanced? and has a 168 tooth flywheel? or am I reading that wrong?

Don

thats the way i read it.

I could be totally wrong, but the way the shift forks are mounted that tranny looks like an early non synchro 1st gear three speed.

Although I've never even looked at that new a small block,I was lead to believe that only the 400 and 454 were externally balanced. That trans does look like an older non-syncro first gear to me also. Hank

If it is an early non syncro what years were these used?


Thanks,

Don

Late 50's early 60's every one I had with a 3spd was non,although I've heard of all synchro in Corvettes as early as 57. I think it's the clamp-on shift arms that identify them.Hank

Originally Posted by halftanked

I think it's the clamp-on shift arms that identify them.Hank

That's what leads me to believe that it's an early tranny. IMHO they are weak and about all they are good for is a boat anchor.

For the application I am using it for, strength is no issue. Plus, I can always change it down the road (not literally ) For now, if it bolts up to a standard chevy bellhousing and regular clutch stuff fits, it will be ok.

My concern also was that since he advertised it as '64-'67 Nova, to me that spells 4 cylinder stuff, and I was afraid it would have some goofy bolt pattern or something.

I know Ford changed their balance from 28 oz to 50 oz in like 1981. Are there similar changes in Chevies, like some were internal up to a certain year then went to external?? Mine is a 1999 5.7 Marine roller cam engine. Does that sound like 168 tooth or 153, or what?


Thanks for all the help, guys.


Don

For the Vortec motor, it is internal balanced but who cares? Go to the Chevy dealer (dont wear any Ford shirts) and ask for a manual flywheel for that engine (98 Vortec). There will only be one that fits, you will not be given a choice of a 153 or 168 tooth wheel. The one piece main engines have a bigger bolt pattern than does an earlier small block so the choice is what it is.

Get the bolts from the Chevy house also. You will have to get a clutch pressure plate to match the flywheel pattern and a clutch disk with the right spline for the tranny. Vortech engines had a hydraulic clutch and would simplify your linkage but cause you to put in a clutch master cylinder.

Have you ever driven a bucket with a stick shift? Make sure you have a washable interior in the thing.......

Here's the way I see it. It's a '65 or older, non-synchro low gear Saginaw. They had 4 bolts on the side cover. In '66 they went all synchro, and have 7 bolts on the cover. The casting date of L271 means December 27, 19X1. The decade is not indicated, but it wouldn't be '71, cuz that would be a syncgro unit. Most likely 1961, and put into an early 1962 model year vehicle.

Bob