I am putting a 235ci motor and 3 speed manual box out of a 59 GMC Apache into my 40 Chevy Coupe, I have different boxes to choose from, the original apache(first pic) which is much bigger and real tight fit or another which i have no idea what it came out of(second pic) which would give me more room to play with. I don't mind doing the modifications to make space for the larger one if it's a better box but if they are both similar i'll use the smaller one. I have Hurst floor shifters for both so gear linkage isn't an issue. On further investigation i think this is a Saginaw box, it has 12W as the start of the code if that helps... Thanks in advance!
That apears to be the smaller 3-spd used from 55 to 65. Non syncro low gear. Not very tough. If you could get a newer 3-spd Saginaw from '66 up it will have a syncro low gear and be alot stronger.
These Muncie 4 bolt cover transmissions get a bad rap, when used with stock column shifters. They get jambed up going from first to second gear, if you try to shift in a hurry. If you can live with the non syncro first gear, and get a good floor shifter with possitive stops, it will last a long time.
Last year I got rid of the last "spare" 3spd I had for my '57 Chevy from 1971! I became an expert on swapping the trans even though I only owned the car for two years! IMHO go with the bigger Saginaw. Your back will thank you!
Wish you were close by--I've got a very good heavy duty 3 speed out of a '76 Chevy pickup that I would donate to the cause, nothing wrong with it, came out of a running truck that was rusted all to pieces, don't need it and it's just taking up space. If you were close by, I'd say come and get it.
Make room for the saginaw in the first pic. Its lits tougher than the muncie in the second. Plus it has syncros on first gear unlike the muncie where you have to come to a stop or double clutch to keep from grinding when downshifting to first on the fly.
The one on the floor is from a 1955 -1957 chevy passenger car. A Truck trans has a rear motor mount on the tailshaft.
Amen to that.... You don't want to be without the synchro on first gear. I had one of those boxes in the second pic back in the day and they had other issues besides the synchro deal. They came in both V8 and six cylinder models. The V8 box has an input shaft that is the same diameter from the splines all the way to the input gear and a first gear ratio somewhere around 2.5 to 1. The 6 cyl box has in input shaft whose diameter decreases as it enters the throwout bearing sleeve and first is around 3.00 to 1. Neither is very strong. They also have a clamping mechanism to retain the shift arms. Unless they've improved the arms in floor shift kits they are a real pita as they slip if you bang on the gears very hard. The one on the floor is a 6 cylinder box. A buddy of mine used to use them in a 62 SS convertible with a 327 back in the 60's because he liked the low first gear. He broke one every couple of months but they only cost $15 at the boneyard so he just kept replacing them.
Thanks for all the advice guys, this place rocks! Yeah i'm taking your advice on the non synco 1st, i had a 54 Bel air a couple of years ago with the same deal and it wasn't so bad as the diff was low enough geared to pull off in second. i have higher ratio axle in the 40 so 1st gear will be used a lot more when coming up to junctions. Very kind of you, unfortunatley i'm definitely not close! Anyone know what sort of ratio 3rd gear would be on the saginaw box?
3rd gear is one to one. Here's a link to a sight with the different 1st and 2nd ratios available http://www.dandltransmission.com/saginaw.html
Thanks, do you know where the lines(grooves) are on the box? Looking again at that page, i guess they mean on the input shaft, that's something i'll have to look at later when i pull the box off.
I have another question, didn't want to clog up the HAMB so i thought i'd ask in here first. The engine i bought is from a 59 GMC apache, I was told it was a 235ci but just doing a search on specs the smalledst engine was a 270ci for GMC trucks in 59. does anyone know how to identify the engine, apart from the GMC rocker cover it looks the same pretty much as a 235 chevy...
post a picture of it. The GMC and Chevy do look similar, but they're not the same. GMC didn't make Apaches, Chevy did. How about some pics of the whole truck too? It's also likely that someone swapped in a Chevy engine, they're easier to find, easier to find parts for, etc.
i don't have pics of the truck, i jusy bought the engine on it's own. I'm guessing the guy who sold it just called it an apache because it looked similar or maybe it was a Chevy truck that had had a GMC engine swapped in? it has the short side plate like a 235 Chevy but the rocker cover bolts are 2 in the middle like a 216 chevy. is this characteristic of a GMC engine? I just checked the engine number, the first three digits are 270, is this a coincidence or does this tell me it is infact a 270ci?
the 270 thing is how GMC numbers the engines. My guess is that it's a GMC 270. The two bolts holding on the valve cover is what Chevy used thru 54, then changed to 4 bolts on the edges in 55. but you can use an earlier valve cover by just adding longer rocker studs. GMCs were all two bolt, afaik.
Casting numbers off the block and head will probably tell the tale of exactly what it is. These engines got swapped around so often when they broke back in the 60's and 70's that one can't be sure that a certain engine came with the chassis it is in unless the serial number matches the truck. i've got on of the Saginaw three speeds in the 48 that I ran for about 15 years and that is the three speed you want even though it's a tight fit. Here is a list of GM inline six block casting numbers. http://www.adchevy.com/info/article/chevy6castingnumbers/ I'm going to piss the wife off and print it out on her printer so that I'll have it.
I'll check those casting numbers tomorrow, So if it's a GMC 270ci, does anyone know if the inlet and exhaust manifolds off a 235ci Chevy will fit?
No, not really. You can cob up a pair of Fenton headers to work on a GMC, but the intake interchangability is a definite no.
Just checked the engine casting number, confirms it's a GMC 270ci. searching around on the internet it seems parts are readily available so i'm pretty happy with what it's turned out to be. Thanks for all your help guys!
Hello again, i have decided to go the 5speed route and am looking for a Borg-warner T5 which will bolt onto the bellhousing, i have found one that is a 1353-055 which is fairly low geared but not so bad as my rear axle is 2.73:1 so quite tall. does anyone know or point me where i can find out if this will have a standard chevy output spline and if it will bolt up to my bellhousing or not??? Thanks
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