Vortec engines came out around 1995......

Your 305 will bolt to the 4L60e...not sure what flywheel you will need. About controling it, Im not sure

 

It should bolt right up but you'll need to retain a lot of the engine sensors as they are integrated into the ecu which controls the trans and the original motor. Specifically you'll need the throttle position sensor and the vacuum sensor. I'm not sure what, if any, other sensors you'll need. I had a Mazda MX6 that required the shift position sensor off the old trans to make the new trans work so you'll have to play with it. Getting the TPS to mount to the carb may take some fabrication unless it's a Holley or another common brand carb. I think Holley makes a kit that bolts onto the throttle linkage to retain the use of a TPS for electronic trans. Check on TCI's website as I'm pretty sure they have one too. Good luck.

 

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. Prolly easier to get an aftermarket electronic transmission controller... GM may even sell one... do a search...

. Yeah, I think true powerful Vortec engines are '96 - 2001... earlier were some wimpy 'Vortechs'...
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If the 305 is from 84/85,it's not a Vortec.Vortecs started in 96.If the trans you have is from the 95 S10,it will be a 4L60E.You need a controller for it to function.There are several that work well.GM sells them.U.S. Shifts is a good unit as well.Mega-shift by the same co as micro-squirt.You will need to tune shift points as well as possibly other mods to make it work well behind the V-8.If your S10 was a 4 cylinder,it will have different valvebody calibrations,TC,etc.You may even be able to use your current controller if you have someone who can do the reprogramming.You will have to retain the TPS,VSS,& use the correct VSS buffer/DRAC for the V-8.Gear selector switch will be needed as well.

 

305 to 4L60E

Vortec identified by 8 x vertical (5/16") attaching bolts, earlier identified by 12 x angled (3/8") attaching bolts.
4L60 uses a TV cable and NO computer, 4L60E uses TCC plug and requires a stand alone computer and a few engine sensors otherwise it won't shift.

 

As has been said, the 4L60e you have must have the computer to control it as an automatic transmission. There are valve body kits to make it a full manual valve body if you want. Otherwise you'll need to hack a factory computer to make it think the original engine is still there, or purchase an aftermarket controller that still requires a certain number of sensors like TPS.

A question that I don't think has been asked... what motor is currently in the S10? If it is the 4.3L then yes, the two bellhousings are the same. If it is the 4-cylinder, then no, it won't bolt up.

If it were my money, a 700r4 is the same physical transmission but not electronically controlled. You can pick them up cheap. You can probably sell your 4L60e and make money on the deal actually. Its a direct bolt-in, physically. Same mounts, output shaft, length, everything.

 

I agree with Curtis. it will be easier to get adjusted and cheaper to go with the 700r4/ 4l60 (no e) with the t/v cable. you won't need a computer to control it. call your local junkyards, and/or tranny shops, tell them what you're doing, and see if they wanna do some tradin. I believe, my 89' 700r4 / 4l60 had 30 spline, and some earlier models had a 27 spline. you need the same splines that's in the 4l60e. if you got the torque converter with the 4l60e, and it was behind a 4.3 ltr , keep the torque converter, it will work great behind the stock 305. stock 305's (88-95 trucks) that came with a 700r4 had a 1350 rpm stall converter with lock up. the stock 4.3's came with 1800-2000 rpm stall converters with lock up. I got a 2000 stall converter with lock up out of a 97' s-10 4.3, and its stalling 2300-2400 behind my stock 89' tbi 305, it works great:thumbup:. you will be needing a torque converter lock up kit, and a 700r4 t/v cable throttle bracket, holley #20-121, if using a holley carb. not sure if it'll work with another kinda carb.