I've got an aluminum bellhousing from a SM465. I'm trying to find out if it can be used for a sM420.

I know that the SM465 and SM420 have the same bellhousing bolt pattern.

But I believe the SM420 has a smaller bearing retainer than the SM465.

Will a SM465 bearing retainer bolt to a SM420 thus allowing the use of the SM465 bellhousing?

Thanks in advance for ANY help,
John

just makes it harder to line up, thats wha ti am using, usually u use the bearing retainer to place the bell to the block and rotate to get teh bolts in, well no wyou have to have help or a hoist! jiMMy

Jimmy, are you talking about bolting the bellhousing to the engine block first and then bolting the tranny to the bellhousing?:confused:

Originally posted by The Jerk
just makes it harder to line up, thats wha ti am using, usually u use the bearing retainer to place the bell to the block and rotate to get teh bolts in, well no wyou have to have help or a hoist! jiMMy

If you're using a small index in a large index bell, you will have problems, it's just a matter of time. The crank, trans input, trans output and tcase input need to be in alignment within roughly .003" to be happy, live in harmony, and reduce accelerated wear. That is why they have a bearing retainer to index on. The bolts alone will not align them properly. You can have clutch problems, trans popping out of gear problems or a number of other problems- unless you get lucky...

the front brg. ret. on the 420 is the same size as std. car boxes so if this is a 420 to chevy for i nstance any car bell housing should work. Defenitely don't want to run it iin the 465 bellhsg.

Originally posted by Lil'John
Jimmy, are you talking about bolting the bellhousing to the engine block first and then bolting the tranny to the bellhousing?:confused: it came out that way but i didn tmean that, cuz you have to run 2 of the bolts the opposite direction with an sm420. as for the allighnment i guess ill just wish on luck for now, he he, jiMMy

I agree that the index hole should be the same size as the bearing retainer, however, if you're bolting a Chevy tranny to a Chevy b/h, the bolts will be in the same place, therefore you should have equal space around the entire index hole/bearing retainer, right?

I have heard that a machine shop can make a "ring" to take up the slack between the retainer sizes.

What advance adapters uses is a indexing ring, It takes a large bore Bell and makes it a small bore bell. I use this setup on my CJ with the sm420..

All the ring does is fit snuggly over the bearing retainer on the Transmission and snuggly in the large hole in the bell.

Maybe call advance and see if they sell the ring seperatly.

Originally posted by Putzboy
I agree that the index hole should be the same size as the bearing retainer, however, if you're bolting a Chevy tranny to a Chevy b/h, the bolts will be in the same place, therefore you should have equal space around the entire index hole/bearing retainer, right?




Wrong. The 1/2x13 Bolt holes and bolt threads have far more than .003" tolerance as far as locating the two together.


the front brg. ret. on the 420 is the same size as std. car boxes so if this is a 420 to chevy for i nstance any car bell housing should work. Defenitely don't want to run it iin the 465 bellhsg.


Wrong again!!! The car bells (some anyways) have an even smaller index than the 420. And alot of them will only accept a 10" or smaller clutch.

Anyone with a lathe should be able to make up a simple alignment biscuit for this... don't just use the bolts Jimmy, it'll lay quick waste to either the tranny bearings or the crank bearings... OR BOTH. You want the crankshaft and tranny input shaft to be damn close to inline, and JUST the bolts isn't close enough. It'd be different if you had a dowel-aligned bellhousing, like the AX15/R150/R151F.

Randii