I was wondering how i should go about this. i have a 1964 chevy c10 longbed and was wondering if i need a shorter/ longer driveshaft and other things like a new bracket for the trans and things like that.
Im not 100% certain but I want to say the sm465 is about 12 inches or so long and a saginaw 3 speed is more like 23-26 somewhere around there. That would lead me to believe you'll need more driveshaft.
Are you sure it has a Saginaw 3 speed? The usually came with Muncie, with non synchro 1st gear. The driveshaft for the 4 speed needs to have a slip yoke in it (since it has a bolt on rear yoke), and a large 1350 series ujoint at the transmission. The SM465 uses a larger diameter bearing retainer than the 64 truck has, so you need to either bore the bellhousing larger, or get a 68-72 bellhousing. But first make sure what transmission you really have now, and what bellhousing. The transmission in those trucks originally mounted to the bellhousing only, which mounts to the crossmember. And there's a light crossmember behind the transmission that supports the parking brake cable, and it might be in the way of the 465, or it might not, I don't remember for sure,. They changed that crossmember by 1966, and used a different parking brake cable****embly that might solve this problem. Also the transmission will hit the bellhousing crossmember, you need to do some grinding, iirc. And the floor is in the way, the 4 speed trucks had a different floor panel that unbolted, but also there was one piece that was different that is welded in. So look carefully into that. I did this swap to a 1965 GMC about 30 years ago, the details are iffy in my mind.
the pre 67 trucks floors had both low and high humps that bolted in. Starting in 67 is when the low hump was one piece with the whole floor. I just went through this my O/T 68 C10 where I went from a 465 to a car Muncie 4 speed. Are referring to the diameter? If you are still running a 2 piece driveshaft they are not very large in diameter. Also another thing to know with the SM465 Bellhousing is they take a starter that bolts to the bellhousing like a tri five. They do not bolt to the block.
I'm not clear on which way you are going. Either way you are going to have to change out the front half of the two piece driveshaft. That goes without question. The Saginaw uses a slip yoke like a turbo 350 and the 465 has a flange that a U joint fits in. Top two drawings being what you will see when you slide under the truck with the 465 as it was too dark to go out and slide under my 77 to get a photo. Flange on the back of the output shaft held on by a bolt with a U joint fastening to it.l Bottom is a driveshaft in a Chevy long bed with an automatic but the same as what you will need with the 3 speed. You also have to make sure that the hole in the bellhousing is the correct size for the bearing retainer on the saginaw or the other way around if you are going from Saginaw to Granny. Some where in there with the 465 the bearing retainer got larger in diameter and the hole in the bellhoising is larger and you need a spacer ring for the smaller bearing retainer. 465 info here . The Novak Guide to the GM Muncie SM465 Transmission (novak-adapt.com)
The starter bolts to the bellhousing on the 55-72 trucks with standard transmission. It bolts to the block starting in 73, and also on the automatic equipped trucks 63-up with the powerglide or TH400, etc.
He will still have to use a stick bellhousing when he swaps transmissions. By all rights and regulations the 64 should have an SM420 in it unless someone swapped a 465 into it at some time. Chevys had SM420 from 47 to 67 and didn't get the 465 until 68. The Novak Guide to the GM Muncie SM420 Transmission (novak-adapt.com) The Novak Guide to the GM Muncie SM465 Transmission (novak-adapt.com) If it has an SM420 it is just take out the middle piece of the floorboard, unbolt the driveshaft and remove it and unbolt the trans and not killing yourself remove it and then decide if you are going to do anything with the cluch or just put the 3 speed in. then figure out the shifter and driveshaft. You guys gotta get your heads away from those automatics though. I've got a close to a 64 v8 bellhousing in my 48 with a Saginaw full syncro 3 speed with a Hurst shifter. That setup worked flawlessly for probably 80K outside of having to replace the clutch a couple of times.
I have 2 OT 1 ton trucks with the SM465, they were there when I got them. One has the winch driven off the PTO and the other does not. I rarely use the low gear, unless I have a load I'm hauling. My first experiences with this setup was when I drove a school bus, and even then we only used low when we had a full load of kids. My setup works for me, but if I was starting from scratch with a pickup, I would rather have a light duty 4 or 5 speed. More fun to drive and easier to source parts for. Either way you'll probably have to install all the parts and then have a custom driveline made. Good Luck.
I had an OT 3/4 chevy truck that came with 3.21 gears, and the 465, and first gear was actually useful in that one.
My '65 C30 had a 5.38 rear in it. I only used 1st gear when I had 4000 lbs of scrap steel in it. This was a SM420.
I’ll chime in. We have a truck someone attempted using an older bell housing with a 465. This 465 has a larger hub diameter than the trans that was used with the early bell housing. I’ve got a 61 with the 420. Both trans use a 2 piece drive as far as I know The 465 should have a trans mount, this will let ya use a later style bell housing. That requires removing the bell housing crossmember from the frame. There’s a couple different hub diameter older style iron bells. The hub diameter is the first thing I check. If that’s good, bolt it up. You’ll need a drive shaft from a truck with the correct yoke, then cut to fit. I’ve cut my own with great results. Oh, the trucks with the 4 speeds had a high hump in the floor. Might have to find or build one.
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