Hi everyone,
I bought my 40 about a year ago with a chevy 350 and a 3speed tranny already installed in it. Now I'm planning on replacing the tranny with an h55f. My question is that would I need new adapters to mate the h55f to the 350?

thanks for any info

Yep,
you need the Advance Adapters 4spd bellhousing and associated throwout arm/bearing.

With the H55 install, you will be cutting a new hole for the shifters
dealing with parking brake issues, driveshaft length changes and possible(and likely) driveshaft flange bolt pattern differences. Overall the tranny/case combo is alot longer than the three speed in there now. Also you will have to deal with a crossmember to support the tranny. The AA rear x-member doesn't work with the split case. Best bet is to get ahold of an FJ60 tranny crossmember as well as the frame rail brakets and go with that. The underbelly of the H55f's are setup for this style of mounting.

I am sure I forgot something...but that should get you started.
-Brett

Do yourself a favor and get a SM420 instead of the H55F.
Granny low 7to1 first gear.
Get a cheap adapter to bolt it to your 3-speed case.

why not go SM465 and drop the adapters:confused:

thanks for all the info..
I'll research the SM420 and SM465 options.
The reason I was looking at the h55 was because of the overdrive
and I also own a fj60, so I was thinking that I could put the h55 in
the 60 later down the road.

why not go SM465 and drop the adapters

Ahh, you'll still need an adapter from the 465 to the 3spd transfer.

Either way, I'd save yourself alot of trouble and go with either a 420 or 465 or even better yet a 700R4 over the H55F.