New drivetrain ideas

So right now I have a 350 sbc, 456 saginaw tranny mated to a dana 20. I wanna get rid of the tranny because I don't like the gearing (too high). I'ld like to just get rid of the tranny but will part with the dana 20 if needed. I don't wanna buy adapters I don't have the money for them. It previously had a Ford top loader that bolted up to the bellhousing as well if that helps.

Oh yeah it's in a '52 m-38.

Any help would be appreciated.:?

 

sorry trying to keep down cost. Damn kids and they're always emptying belly's.

 

The Saginaw 4 speed came in four different first gear ratios. I'd need to know what yours is. I run a Saggy 4 speed in my '59 CJ-5, have for a lot of years with a Buick 231, 18 transfer case with 246-1 low range, and 5.38 gears. I run the widest ratio with around a 3.5-1 first gear. It works pretty well in all terrains. Doesn't shine in any one except maybe sand/mud but works well in the others. Tire size makes a big difference with these. A 20 stock has a 2.03-1 low range so that could be part of the problem. Knowing WHICH saginaw you have and tire size and terrain you are running would be helpful in knowing what way to direct you. The only way to get lower gearing is to gear down the 20, possibly gear down the Saginaw depending on which one you have, going smaller tire size, or gearing down the axles.

 

It's a 456 out of the 80-82 firebird. My axles are 5.38 already and i'm running 31's for tires now and a maximum of 33's in the way distant future. Terrain is mountain and I really wanna stay out of mud and lots of snow in winter.

 

After doing some research into maybe a sm465 I need to buy a different bell housing for that too work and mating it to a np won't work cuz it's too big from the sounds of it. Can someone confirm or deny this?

 

So your axles are 5.38 and you are too high on the gears????? That doesn't make any sense. First gear on your current tranny should be about what a truck 4-speed would be in 2nd. If you use 4-low you still have a very low crawl ratio with the 5.38s.

 

Well the dana 20 is 2.03 I think so with the 5.38 and the high geared tranny with a maximum of 38:1 crawl ratio. And that's assuming I have the 3.5 first gear but I don't know what it is. I want something deeper into the 6.5+ granny first gear to get it closer to the 65-70 maybe ?

 

How about one of the terra low gear kits for the Dana 20? They're not cheap, but by the time you change out your trans & transfer case for something else, you're looking at some serious cash anyway...

 

I should have clarified when I said the only way to gear down I meant without changing out the transmission or transfer case. With my set up I have around a 46-1 crawl ratio. I'm not sure which ratio your tranny has or what came in those years of Firebird. You'd have to do some research on that but the highest first gear ratio of the Saginaw was in the range of 2.5-1 so if you have a close ratio unit that is most of the problem. You can gear down the 20 using Early Bronco and 18 transfer case gears to 2.46-1 or going with an aftermarket kit to go to 3.15-1 low range. A T-18, SM-465, or similar is a good way to go as well but none of these is really cheap. All depends on how much money you want to spend and how much work you want to do. You said in your first post that you don't have the money for adapters so that leaves out the SM-465 and SM-420. The T-18 is possible with using factory adapters and some inexpensive machine work, but is still not cheap.
I'd consider finding out what ratio your transmission is now. If it's the close ratio then see if you can find a wide ratio unit that you can swap the gears into your transmission and maybe do the 2.46-1 conversion in the transfer case.
One think you might want to think about, Cheap and Jeep do not go in the same sentence together.....

 

Yeah lol I'm seeing that it isn't cheap. thx for the input and ideas.

 

I know wheelbase is an issue in a flatty, but have you considered an auto? A TH350 might be just the ticket. Yes, you'd still need an adapter for the D20. You could do a TH400 with a factory Jeep D20 adapter. Driveshaft length will be a problem, but others have made it work.