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Bell housing bolt size

Cadden

Cadden

1/2 ton status
Joined
Jan 28, 2020
Posts
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Location
Oregon
Hey guys. I took a break after getting my transmission and transfer case in the old jimmy.
Now I'm getting back to work on it before the rain starts here in oregon.

I remembered that my bell housing seems to need 2 longer bolts. But when I look up bell housing bolt kits or sizes they are all the same size?

See picture. 4 are the same size but I think 2 need to be longer (see circled bolt hole in picture)

20200907_092640.jpg
 
The hole on the left side of circle is not a mounting hole. The one in the bottom center is and you have one more on the left side of bell housing not seen in picture. All sources say they are all the same length.
 
frankin5 said:
The hole on the left side of circle is not a mounting hole. The one in the bottom center is and you have one more on the left side of bell housing not seen in picture. All sources say they are all the same length.
Click to expand...

So I'm once again probably just over thinking this? The heck is the hole for then?
 
Here is a screenshot from a recording I just made.
You can see the alignment dowel or whatever you call it in the middle. And 1 of the 4 bolts that kind of go around the top half of the bell housing

And on the bottom its the starter bolt holes *this is the passenger side. Driver side doesn't have the extra bolt holes but does have the same longer hole like the one right below where the dowel pin is resting.

20200907_221339.jpg
 
Or is it that even though it seems like I need a longer bolt that I dont?
Man I really wish I was there was this thing was taken apart
 
Most GM vehicles had a stud in the bolt hole above the dowel pin for the dip stick tube bracket to bolt to factory..
If I remember correctly the bell bolts were 1-1/4" long ,3/8 x 16 thread..
 
Cadden said:
Here is a screenshot from a recording I just made.
You can see the alignment dowel or whatever you call it in the middle. And 1 of the 4 bolts that kind of go around the top half of the bell housing

And on the bottom its the starter bolt holes *this is the passenger side. Driver side doesn't have the extra bolt holes but does have the same longer hole like the one right below where the dowel pin is resting.

View attachment 352382
Click to expand...
you want the one under the one circled.
 
Nope. The last hole that lines up with anything is that deep one. I bought a bell housing bolt set. All 6 bolts are the same length. Those last two spots don't even start to thread.

Below the starter side one, are the holes for the starter.

So is it supposed to be a stud, or a longer bolt on those bottom two bell housing holes?

20200919_175256.jpg

20200919_175344.jpg
 
The spot above the black bolt in my photo is a a giant alignment pin or Dowell.

The black bolt is from my new bolt set I bought from summit
 
If that is a cast iron bell housing for a SM465,then it may have longer bolts than the 73-87 trucks did with aluminum bell housings.which is what I'm most familiar with...

I did swap a '72 K5 from a TH350 to a SM465 that had the cast iron bell housing,with an open bottom,and the starter bolted to the bell housing,not the engine block..but that was back in the mid 80's and I cant recall if I had to use longer bolts ,if I used the ones I got off the donor truck,or something else I had lying around now..

I do have a 1946-72 GM parts catalog for 10-30 series trucks that may list the dimensions,but its in my garage ,not where I am now,but if your in a bind I'll try to look them up tomorrow..

You want bolts that'll screw in at least the depth of threads a nut has,without bottoming out and grade 5 or 8 is best..
 
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diesel4me said:
If that is a cast iron bell housing for a SM465,then it may have longer bolts than the 73-87 trucks did with aluminum bell housings.which is what I'm most familiar with...

I did swap a '72 K6 from a TH350 to a SM465 that had the cast iron bell housing,with an open bottom,and the starter bolted to the bell housing,not the engine block..but that was back in the mid 80's and I cant recall if I had to use longer bolts ,if I used the ones I got off the donor truck,or something else I had lying around now..

I do have a 1946-72 GM parts catalog for 10-30 series trucks that may list the dimensions,but its in my garage ,not where I am now,but if your in a bind I'll try to look them up tomorrow..

You want bolts that'll screw in at least the depth of threads a nut has,without bottoming out and grade 5 or 8 is best..
Click to expand...

No rush or bind. This has been a project for the last 9 months. Just trying to button up the small things.
Just got the front clip back on and going thru wiring.
Im also waiting on two orders of parts that just sort of stopped moving 3 days ago per the tracking number....

20200919_131516.jpg
 
This is definitely just one of many small discrepancies I've come across putting this thing together lol

I've scoured the internet and every single thing that comes up says all bolts should be the same size
 
I think I finally found a listing for what I need.
The sizes seem off to me though. Thought the main bolts along the top were supposed to be 1 3/8

Screenshot_20200920-205551_Chrome.jpg
 
I use this cast bell, was factory on my 350/SM465 and bolted right up to my '74 454 :saweet:
A bit dirty and I use a newer High Tq starter, it's GM but I can't recall the year, they are a smaller starter with a higher Tq rating :waytogo:

Pass_side.jpg

pass_side1.jpg
 
Cadden said:
The spot above the black bolt in my photo is a a giant alignment pin or Dowell.

The black bolt is from my new bolt set I bought from summit
Click to expand...

Those are sharp I am going to have to get me some. I am constantly losing trans bolts even after switching to a high grade bolt and lock washer. When I pulled my trans a few weeks ago on the '80 one was missing and had a couple of the lock washer come off in two pieces. I dont know.
 
chevyjunky77 said:
Those are sharp I am going to have to get me some. I am constantly losing trans bolts even after switching to a high grade bolt and lock washer. When I pulled my trans a few weeks ago on the '80 one was missing and had a couple of the lock washer come off in two pieces. I dont know.
Click to expand...

If you're not getting the right size and to long or to short it'll do that. Which is why my brains being so OCD about this lol
 
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