I am currently planning a LS3 build for a 83-88 Monte Carlo SS but I havent quite settled on a transmission type. Both have about the same pros and cons for me. If I go auto I will use a 4L80e and if manual i will use the T56 Magnum. What is everyone's thoughts?

 

Not enough info to make an informed choice. What's the intended use - drags, road course, street car, daily, etc? How much power do you plan to make? What setup do you plan to run?

In general -

If dig racing is the goal (street or strip), it's got to be a 4L. It's far easier to go fast consistently with an auto, and itll be easier to live with a big nasty drag racing cam.

For a 'weekend's street car, I'd go t56. It's a lot more engaging to shift your own gears and becomes an enjoyable part of the experience IMO.

 

It will be mostly a street car with some track time. Looking at about a 95% street 5% track, probably less than that for track honestly. It will be a N/A LS3 that I will be building from the ground up. I am looking to make around 500-550 at the crank.

 

IMO, T56 all the way. It's a lot lighter, consumes less power, and will even give better gas mileage. Also would be a lot more fun (again, IMO- even a MVB isnt the same experience to me).

Clearly either will easily handle the power. Only downside I see to a t56 is the initial cost. Certainly 'built' models of each can be comparable, especially depending how crazy you go. But if you were planning to just get a stock junkyard unit and chuck it in, it's easier and cheaper to get a 4l80.

 

Every car I've ever driven feels like it has an extra 20% hp with a stick in it vs. it's AT counterpart and it's way more fun to drive. T56 all the way

 

I would take a manual over the Automatic every time. However you may have a tendency to ride the clutch or shift a bit screwy, may cause some fineness on the part of the driver.

 

With all things being equal I am planning on buying new. whether I get the auto or amnual. I plan on spending a good deal of money on this project for the motor. it would be foolish to skimp on the rest of the drivetrain. The good thing is I have some time to save and plan so when it comes time to buy I should have a good chunk needed already.

 

TBH, if the OP has either of those issues, then the T56 is not the right trans for this project. A performance clutch and 500+ crank hp car is not the right way to learn the basics of how to drive stick.

 

That makes it a toss up on price then depending how extreme of a build you go. I'd still lean towards the T56 though, I dont really see any benefits to the 4L outside of a drag race application.

Shouldn't have to spend much on the engine though as your power goals are very reasonable. Just grab a donor engine from a reasonable mileage car, chuck a cam and headers on there and you're done. Add some ported heads or a pretty aggressive cam and you could easily hit your upper target. LS3s rock!

 

I use to has a 1980 Oldsmobile Cutlass with a 3 and a 4 speed manual transmissions. Banging gears is a great time but I would go with the 4L80E . Either way is a great choice.