Can you use aluminum bell housing on 72 and earlier?
 

I searched but didnt see any specific posts. I have two 465/205 assemblies from a 74 K10 both with aluminum bell housings. Can I use these for an auto to manual swap or do I have to go to the cast housing?

thanks

Re: Can you use aluminum bell housing on 72 and earlier?
 

GM did, why not?

Re: Can you use aluminum bell housing on 72 and earlier?
 

You mean cast iron, right? Both aluminum and iron bell housings are cast pieces. I didn't know GM used aluminum housings in 4spd later on. I guess that worked out, but it does seem right to have a cast iron housing connecting a cast iron engine and transmission.

Re: Can you use aluminum bell housing on 72 and earlier?
 

I guess the wording was a bit wierd. I do not have a cast iron housing but I do have two good 73 up aluminum housings.

I would like to use the aluminum housing if possible but looking at both types I noticed the Z bar ball on the aluminum one screws directly into the housing while the cast one uses a bolt on bracket. Since I dont have a cast iron one on hand to measure any difference in location I was wondering if the Z bar will even work when using the late housing on an early body/frame

Re: Can you use aluminum bell housing on 72 and earlier?
 

Tomorrow I will try and get you some pictures, I have an 83 aluminum bellhousing and a 71 cast iron bell housing and even different is the 87 bell housing on my K5 which has hydraulic clutch. And we can see if we can get you some answers.

Re: Can you use aluminum bell housing on 72 and earlier?
 

Thanks I appreciate the replies.

I would like to see any differences in housing width (engine flange to trans flange)

What I think I need to figure out is the z bar situation. Are 71-72 z bars the same for 2wd vs 4wd?

Re: Can you use aluminum bell housing on 72 and earlier?
 

I have seen differences, can't recall just what, why, or when. But I have also seen the factory use mounting plates for the pivot ball to move it's location forward or back

Re: Can you use aluminum bell housing on 72 and earlier?
 

Most blocks will have either a hole already there for a pivot ball, or there will be a boss, just have to drill and tap. But I don't know if that was for trucks or cars. I did one to a car, but thinking it is for cars and not trucks. I had a 75 and 84 that had the ball on the bell. Made it fun wheeling, putting it in 4 low with shot motor mounts would let the motor twist enough to let the z-bar fall out.

Re: Can you use aluminum bell housing on 72 and earlier?
 

^^^ That's how it got on the '77 K30 I had. It would 'torque' itself loose at the worse time, like in a bog or hill climbing

Re: Can you use aluminum bell housing on 72 and earlier?
 

B454rat I believe you are correct it does mount to the block atleast my buddies 67c20 did. I feel your pain on the clutch z-bar special-k thats exactly how my74 k5 is now but I have newer motor mounts and a fairly healthy motor it's a royal pain in the you know what to have to fix it on a hill because it's stuck in gear and there isn't a vehicle big enough to flat drag it to a better spot

Re: Can you use aluminum bell housing on 72 and earlier?
 

I'm not sure if I did it to the 84 or not, but can always put a chain on the driver side to limit movement. Back in the day I had a car that the mounts were TOAST, so bad that doing a line lock (power brake as some say), with the hood open you could see the motor completely lift off the mount. I put a small chain on it to keep it in place.

Re: Can you use aluminum bell housing on 72 and earlier?
 

I have a '74 K20 with the aluminum bell housing sm465/205 It has held up for over 20 years behind a 454...I removed the original 350 engine 350 auto trans/205 combo in 1995 and haven't had any issues with the alum bell housing, I recently removed the cast iron bellhousing , and sm465 trans/ 205 in my '72 K20,trans case was noisy, I had a setupfrom a '74, I installed it with no problems, just had to use the old clutch release arm, and had to change the pivot ball from the old cast bellhousing to the aluminum housing, I like using the alum bellhousing , it is so much lighter and I can use the 2-bolt starter like the rest of my trucks use... we did the same setup in my sons '70 gmc K20

Re: Can you use aluminum bell housing on 72 and earlier?
 

My mounts were all good. A lot of the problem was frame flex, then there was that rat 454, 4.56s, and 37s

This thread has good info:
https://www.google.com/url?sa=i&rct=...52106877294960

Re: Can you use aluminum bell housing on 72 and earlier?
 

It does seem to be frame flex even though my 350 isn't a torque monster but with 3.73 gears the torque it does have gets put through the drivetrain. I have had it come loose when it was burried frame deep in sand as well as mud. And a few up hill battles that when i decided to let off and get another run it pops loose