An LS engine can be made to mate to a T5. I’m planning to do it, but life has gotten in the way of getting it done soon. A Chevy cast iron bell like the one in the pic below will bolt up to an LS block (minus one bolt). The same bell is shown on my 5.3 LS engine on the run stand picture). A hydraulic throwout bearing will be the easiest solution for the clutch.
As mentioned, to make it a good driver that is both fun and useful, you’ll need to look at the T5 gears and how they match up with the rear axle gear.
An S10 T5 will have either a 4.03 or a 3.75 first gear. The difference is barely noticeable and since the amount of time you will spend in first gear is minimal, either of those gears will be fine for a daily driver. It is a quick shift. I have a 4.03 first gear in my 1963 C10.
For highway driving, ideally your fifth gear multiplied times your rear axle gear should end up around 2.80 - 3.00. (Example: 0.72 x 3.90 = 2.808). An LS engine will have enough HP to pull the truck along with a numerically lower result.
One question to consider is how you will drive the truck. A T5 in proper operating condition is rated for 250 hp and 300 foot pounds of torque. If you plan to spin the tires for fun, it would be best to choose a different transmission. The T5 will not take abuse.
Lastly, the bolt flange on the rear end of a LS crankshaft is 0.4 inches closer to the center of the block than a first or second generation SBC. Therefore, a SBC will need different modifications to the input shaft then an LS engine. I will save that discussion for another time.
Depending on the price, you should grab that 1992 S10 T5. They are becoming very hard to find and you will likely not take a loss if it’s in good condition.
