Swap "granny gear" 4speed to a m20 4 speed muncie

[1968stepside]

Hello,

I have a 1968 c10 stepside with a 350 and a 4 speed manual. I can pick up a muncie M20 for a good price. Has anyone ever installed one of these in their truck? Is it something that is fairly easy to do without any major modifications? Is there a better inexpensive transmission solution I could look at? Any advise would be greatly appreciated. Thx
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[jhwkns]

I've got a Saginaw four speed.They came in Camaro's, monza's vega's, etc. from '66 - '86. They aren't as strong as a Muncie, but don't cost nearly as much either. They are quiet, and very smooth shifting when in good condition.

Here's an >>>ARTICLE<<< They're getting a little tougher to find lately, but it's an easy swap. I think it should bolt right in for you with the same drive shaft and all. I know it's a direct swap for a stock 3 speed in our trucks. The gearbox in the picture has the Hurst linkage kit made specifically for our trucks equipped with this trans. It puts the shifter far enough forward to use a bench seat.

[LockDoc]

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Type "car 4 speed" into the Google search box at the top of the page, click on the circle in front of 67-72chevytrucks.com and click on the Google button. Quite a few have done the swap. I did it on my '67 stepper.

LockDoc

[Lattimer]

Originally Posted by jhwkns

I've got a Saginaw four speed.They came in Camaro's, monza's vega's, etc. from '66 - '86. They aren't as strong as a Muncie, but don't cost nearly as much either. They are quiet, and very smooth shifting when in good condition.

Here's an >>>ARTICLE<<< They're getting a little tougher to find lately, but it's an easy swap. I think it should bolt right in for you with the same drive shaft and all. I know it's a direct swap for a stock 3 speed in our trucks. The gearbox in the picture has the Hurst linkage kit made specifically for our trucks equipped with this trans. It puts the shifter far enough forward to use a bench seat.

I have one of those on my workbench that's going in this weekend.

[MARKDTN]

Do you know anything about the one you got a deal on? In my experience most used ones are pretty well done when they come out. By the time you rebuild it, you spent enough to get what you wanted in a 5 speed. Just a thought.

[1968stepside]

The guy had it in a car for about 1 year after having it rebuilt. Them he swapped to tremec and was selling this one for around $400. He was asking $800 but it sat for a couple months online and no one bought it so he kept dropping the price.
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[54belair]

Im changing mine over to an M20 as well. In your case it should be a very easy transition. Im about a month away in my build from fitting the engine and tranny back in--so I dont have any tips to share yet on installation.

[0608272c-10]

I got one in my truck its so nice just had to swap out the bellhousing and clutch
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[Longhorn 70]

If you are going to do the 4 speed, why not do the 5 and have overdrive?

[1968stepside]

Mainly looking at a swap to a 4 speed because I can get a decent deal on a M20. I know tremec TKO 500 or 600 are the way to go but I don't have that kind of cash flow right now...
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[Longhorn 70]

at least they are pretty much drop in when/if you do go 5 speed. I was thinking about the fuel saving payoff..... stoooopid sassifrassin gas prices.....

[sir_talk_alot]

Id love to find an m20 i met a guy who had a couple and was gonna give them to me. They sat in his shop and he wanted them to be used by someone. Dont know what happened. He went from they are yours to no answer, so i gave up. And nothing shows up on craigslist so if you found a deal get it.
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[Mike C]

Make sure if you do this swap for an aluminum case passenger car Muncie, you get the wide ratio and not the close. The close has a 2.2 first gear and required at least a 3.73 rear gear. And that was with shorter passenger car tires and usually MUCH more powerful engines.

And when talking 4 speeds, remember the truck granny 4 speed option id is ALSO M20 which was GM's designation for a wide ratio 4 speed manual trans option.

[Kjun_kid]

I'm bringing this thread back up to ask a gearing question. I have an 87 stepside that i plan on putting my Muncie M20 into. The truck now has the TBI 350 and 700R4 with im guessing is 3.08 gears in the rear end because at 70mph im at about 1800 RPM. When I swap to the manual will this gearing be ok for being in traffic or am i going to constantly have to ride the clutch? The reason I ask is because a guy I know local has an 87 with a 5.3 with a t56 which has a lower first gear then I have and he's got the 3.08 as well and told me he has trouble in stop and go traffic. Should I put 3.42 or 3.73 gears in it? I'll be running a 5.3 as well, and im sure cam might have a lot to do with how well the truck idols in traffic with a load on it compared no load. I just figured that these truck came with a TH350 and 3.08 gears with a low horse power 305 and they seem to get around just fine.

[67 chevelle]

You will be fine with 308s if you switch to 373s you highway rpms are really going to climb unless you keep the overdrive

[Kjun_kid]

Originally Posted by 67 chevelle

You will be fine with 308s if you switch to 373s you highway rpms are really going to climb unless you keep the overdrive

Yeah thats why I don't want to go with 3.73 but I just want to make sure that im not going to have to ride the clutch in a traffic jam. I'd like to be able to let of the clutch and let the truck just roll at an idol. According to the calculator with 3.08 and 28" tires i'll be around 2500 at highway speed which isn't bad at all in my opinion.

[54belair]

This combo should work for you-----unless you are wanting to jump from light to light. This combo will give you ok city driving and decent mileage on hiway driving.
This is the combo I have in my build, spent some time crunching the numbers---it will work. Now, with that said, I also have to say you need an engine that will produce low end torque instead of high end H P. If you have a cam that produces power in the higher ranges, then your stop and go will suffer. I went with an old style "rv cam"---something that starts pulling at about 1200-1500 rpm. If youre cam gives you a power band starting much higher than that---You might think about the 3;42's
Im old and don't give two hoots about a lopie cam, the stock and the "rv" cam will give you the low end to work with the 3.08's (I know you said you had an M20 so Im just throwing in this for fyi----If you could come up with a borg-warner t 10--------that would work even better, it has a 2.64 first gear opposed to the M 20's 2.56)