Pitstop

[Pitstop]

New owner of a decent 81 Malibu 2-door. Original V-6 car. Supposedly has a 383 small block (but I'm not sure how to prove that yet) and a TH350. Car has a lot of little things that need attention yet the platform and drive train seem very solid. No rust!

Long term goal is to turn it into a reliable and comfortable cruiser suitable for "Drive & Drag" events. Probably build an LS to install down the road. Maybe even add a bit of boost to the picture as well.

First I need to figure out the best transmission choice to make it highway friendly. And any hints on rear end gearing would be welcome.

I did not have anything to do with the car's paint color but honestly it's growing on me.

 

[t5montecarlo]

Very Nice! Where did you find a rust free car?

A 3.73 rear and a transmission with overdrive make a good combination for acceleration and highway cruising.

 

[Pitstop]

Very Nice! Where did you find a rust free car?

A 3.73 rear and a transmission with overdrive make a good combination for acceleration and highway cruising.

Atlanta area car, mostly garage kept evidently. Originally factory color was some kind of faded mustard yellow.

3.73 rear gears was where I was leaning. Didn't have much more than a hunch as to why other than it seems to be a popular factory ratio these days.

Right now my best bet is to go with a 700R4 transmission. Still researching that but it's where I've landed so far. Looks to be a relatively straightforward swap from my present TH350.

 

[t5montecarlo]

The TH-700R4 is 3 inches longer than the TH350 and will require a custom crossmember and a shorter driveshaft, but the TH200-4R is the same length as a TH350 and you can use a Monte Carlo SS crossmember if you add the extra piece to your frame. If you want a custom dual hump crossmember, the crossmember factor is moot.

If you are changing the rear to a 9 inch or 8.5 inch, then the driveshaft length is also no longer a concern.

The TH200-4R has closer ratios than the TH700-R4, which has a numerically lower 1st gear.

I am partial to a manual transmission with overdrive.

 

[Pitstop]

The TH-700R4 is 3 inches longer than the TH350 and will require a custom crossmember and a shorter driveshaft, but the TH200-4R is the same length as a TH350 and you can use a Monte Carlo SS crossmember if you add the extra piece to your frame. If you want a custom dual hump crossmember, the crossmember factor is moot.

If you are changing the rear to a 9 inch or 8.5 inch, then the driveshaft length is also no longer a concern.

The TH200-4R has closer ratios than the TH700-R4, which has a numerically lower 1st gear.

I am partial to a manual transmission with overdrive.

Obviously the 200R4 showed up everywhere I saw anything about the 700R4. Is one majorly superior to the other? Like the lower 1st gear in the 700R4, is there anything particularly positive or negative in regard to that? I had seen that these two transmissions had different first gear ratios but the variation seemed small enough to not be an issue.

I took a tour of your website and plainly see that you prefer to do the shifting. I've become too lazy to follow your example these days. But I can state that there is nothing like swapping gears under maximum load to make you feel at one with a good ride.

 

[t5montecarlo]

I think with enough money, either transmission can be built to handle a specified torque rating. I don't know about cost of each.

Some people like the lower higher numerical 1st gear ratio of the TH700 because it feels like having a higher numerical ratio rear gear, (I made a mistake about expressing the 1st gear ratio in my original post) but there is a bigger drop in rpm when shifting to 2nd gear.

 

[Mighty]

Would you stick with a 700r4 or whichever you choose if you do decide to go LS down the road?

 

[Pitstop]

Would you stick with a 700r4 or whichever you choose if you do decide to go LS down the road?

My initial thought is "yes". But I have yet to dig into what electronics would be involved with choosing a newer option. For that matter I'm not completely aware of what electronics go along with an LS swap if one intends to get the most out of it. I could easily be opening a can of worms that I am not prepared for. Still, I welcome the challenge and have watched too many TV shows where they bolt a big turbo onto a junkyard LS and make 1000hp! Who cold say "NO" to that?

 

[Mighty]

That’s a tough call if you’re really going to do the LS swap and put a turbo on down the road. As far as tuning every last little bit out of it, a 4l80 would be the way to go. I’m not going to lie, before I dug into my Malibu I kicked around the idea of putting a LS2 together that we have laying around and throw a carburetor on it but I wanted to keep the 4 speed in it and not have to cut it up any. My car needed quite a bit of work due to worn out parts so I just stuck with the sbc that was already in it. There’s a bunch of good write ups on swapping a LS into a gbody on the web though.