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I'm starting on a 68 c10 that I got with no enine or trans or driveshaft. Looks like it had a 4 speed in it as it had a floor shift. Vin says it has an inline in it but it looks like it had the side mounts in at one time. I am putting a GMC 302 in it that I had built for another truck. I will have to fab a front mount but I need to find the rear crossmember. It has a 3.73 rear. My question is how can I find out what trans it had. Or what do you think would be a good one with the rear ratio and a 302 inline. Thanks.

T-5 with .86 overdrive. You will be amazed at how the inline 302 will perform with that setup. If you had a 4.10 rear end gears, a .73 overdrive T-5 would be the ticket.
If GM would have came out with a T-5 in 1947, they would have run the completion out of business. The extra 2 gears and the overdrive are that impressive.

Thanks for the info. Would that be found in a s10.

The original six would have had side mounts as more than likely it was a 250 cid. The later sixes 230, 250 and 292 all had provisions for side mounts. the GMC 302 will need to be adapted for engine side mounts, it's doable.

T5s are in the s10. “Lugnuts” on this site is the one to ask about them. However, he’s in SC dealing with Helene.

i've read some of his stuff. He knows a lot about them. I need to research more on how to tell what ratio it is and all the variations. I don't know what model of 4 speed was originally in it or how hard they are to find. Do like the idea of the t5 though.

I'm aware The GMC 300 engine is a big tough engine. It is very heavy. But I believe you will be going backwards putting it in a 68 model truck.
Do you know what was originally in it. You can tell by the serial number weather it was a v-8 or 6 cyl.
I think you would be better off putting a 292 or 250 6cyl. in it. or a small block v-8. That would be almost a direct drop in
swap. Any modification needed would be readily available parts. You might even have to change the front springs to use the 300 engine
I'll agree the T-5 transmission would be a great addition for what ever engine you use. I have put in several of them. You may won't to consider
one with the .o73 o-drive ratio instead of an .086. It depends on what engine you use.

George

I stumbled in on this thread by accident.
If the T5 has a readable tag, then this CHART can tell you what the gears are. However, it’s often wrong!
If you live where there are hills, then be careful not to get too much overdrive or you’ll be downshifting at every incline.
A T5 in serviceable condition is rated for 250HP and 300 lb-ft of torque. It will not take abuse but makes a great daily driver.
T5s are pretty hard to find these days, but they do show up if you search FB marketplace and swap meets.
The S10 T5 from 83-93 will have a Muncie bolt pattern where it bolts to the bell. The 94 and up T5s have a Ford bolt pattern.
The Camaro versions are Muncie from 92 and earlier. The Camaro versions have the shifter further back and that won’t work well with s bench seat.
The Ford Mustang versions have nice gear options but you’ll need a $170 adapter plate to bolt to a Chevy Muncie pattern bell. I’d stay with the S10 versions.
A cable speedo will work if all the right pieces are assembled. Video of S10 tail swap with cable speedo connection.

I know the 302 is a big engine. I built it for a 54 5 window i was doing. It is going to sit pretty high so hood clearance will be tight. Thanks for all the info.

It had a 6 in it by vin number.

Your vin number begins with C, then either an E or S. Those Id Eight or Six.
68's still used the 420 transmission, 69 introduced the SM465&435.
If the glove box lid is still there, the paper "Spid" will have the opted motor it came with. 307 was the standard 8, not shown, optional 327 would be on the spid sheet. A 250 was standard,not shown, optional 292 would be on the glovebox spid

It is a CS. But I have no build sheets either on the glovebox and the one behind the seat turned to dust.

I have found a t5 and according to the number it its a 92 s10 trans w/ a 2.5. Is that the same trans as one from a v6 truck or is it a lighter torque rating? Thanks

cw54 - Can you post the ID numbers from the transmission. That will allow folks to provide more accurate answers to your question.

I found one 1352-211 and a 1352-010.

Guessing that 1352-211 is the code on the stamped ID tag bolted onto the transmission??? The below chart extract shows the gear ratios for this one starting with reverse, then 1st through 5th final drive. The chart does indicate that code matches to the vehicle you mentioned, plus it is not a WC (World Class) unit. The 1992 unit would be an electronic speedometer module unit.

Your 2nd number 1352-010 is from a much earlier 1982 S-10 w/4 or 6 cyinder engine, different gear ratios as noted in the 2nd picture, also not a WC unit, but would have a mechanical speedometer drive.

Are both tags on the same transmission? Maybe someone converted the later electronic speedo to a mechanical speedo drive? Really need to see some pictures of what you have to try and help further.

Fellow Bolter Lugnutz posted above about how much HP and Torque a sanely driven T5 can handle and be reliable. He may be the most knowledgeable person to answer your question about if a V-6 T5 is any stronger or not.

These were 2 different transmissions. I went ahead and picked up the 211 so I can move on with building mounts. I will deal with the speedo drive later. Thanks for the info.