3spd to 4spd swap help needed

[bueller60]

This is my first post so be kind. First of all, great site. I am the proud owner of a 68 Chevy stepside with a 250/3spd on the colunm. I can live with the 250 but the 3spd on the column is driving me nuts. I found a cheap 4spd (sm465) out of a 69 3/4 ton on Craigslist and made a deal. Once I got the tranny home, I started looking things over and now I need some help. Is this tranny going to bolt in? The 3spd has tranny mounts that attach to the bellhousing with no other crossmember. The 465 looks like it needs a regualr crossmember bolted more rearward?? If needed, I could go retrieve the crossmember from the parts truck. Also, I'm almost positive that my truck has a low hump floor. Does the 465 need more room or will it fit? Lastly, the 465 has a yoke with a U joint bracket attached....my 3 spd has the driveshaft slide into the rear of the tranny. Do I need a different driveshaft or ?? I could use some help from the experts. Thanks in advance.

[qksilver]

you will have to convert to a high hump, other than that I would recommend getting every part that you can off the parts truck, it will make the swap a lot easier

[kwmech]

You'll need the 465 bellhousing, the center hole is larger for the nosecone of the 4 speed, so as stated before get all the parts you can off the donor truck.

[Brad]

I would stick with the 3 speed. You'll have to get a slip yoke and have the front drive shaft reworked for a slip yoke. You'll need a new clutch and pressure plate and with all the money you're going to spend you'll have a crappy, unuseable 1st gear unless you're going to tow with it.

I'd sell the 4 speed to a 4x4'er. Oh btw, welcome to the board.

[ThatOneBlue67]

It'll pretty much be a 3spd, cus you'll never use the low gear in most circumstances.

We all have our different applications, but if you plan on putting ina V8 or something racey, may wanna consider a four speed out of a Camaro..... I want to do that.

[crazy longhorn]

With a high hump floorpan added, that trans should bolt right in. You will need to swap the driveshaft,as the lenght is shorter on the 4spd(as you have no doubt allready seen). The bell is not a problem, unless its 67 or older.....67-back had a 4 11/16 centerhole(same as car), & 68 on were 5 1/8" on the hole & it didnt matter 3 or 4spd. That big 4spd trans did hang right on the bell, with no crossmember under it ,so it shouldnt be a problem. I do have to agree that a car type 4 spd would give you better(more useable ratios) for everyday useage tho.....then again, if you pull a heavy load from time to time, that "granny gear" may be just what you want. Best of luck..... L

[69_hafton]

If you're not planning on towing tons of weight, you might consider the new process a833 trans from Chevy 1/2 tons from 82-86. Kind of hard to find in some areas, but it's a 3 speed with overdrive and is perfect fit for a 6 cylinder with 4.11 or even 3.73 rear end. You'd have to remove the crossmember for the manual and put in a automatic crossmember (for 67-72's) and redo the driveshaft - takes a slip yoke. Good for lower rpm highway use than what these old farm truck came with originally. Pricewise you'll pay more for one than the old 4 speed with granny gear trannies though.

[qksilver]

I am also a fan of the A833, great trans

[Americanrider]

Sell it and get a Sagniaw 4 speed, it will bolt right up and it's the same size as you 3 sp. Throw in a floor shifter and drive!. Welcome aboard.

[krue]

Welcome to the board.