Woody, not trying to hijack the thread but you mention your new 3.55 setup. How's that working? I've ordered a set, have yet to get it.
I didn't do the work myself... I'm a sheetmetal guy and know when to turn the heavy stuff over to a professional. I'm VERY lucky to have a guy (genius, actually) 5 miles away who does a lot of work on classics and modifications. I made it a point not to pester him but I did stop by one day to see how it was going and the whole rear end was in pieces, I guess because I had him rebuild it while he was in there. He charged me $350 for the labor. I bought the parts from Patrick's.
I can't tell you how difficult it was but I can tell you he did the whole job without opening the manual or referring to the skimpy directions and vague photos that Patrick's supplies. The installation seems perfect... the rear end is now silent. Whatever wear was there is gone and the gears are perfectly set.
The gears make an immediate impact on driving. My 216 still isn't happy over 45 but I'm going to swap it out for rebuilt 235 so that's a moot point. For low speed driving around town, the taller gear means a change in driving habits. Whereas before I could drop down into 3rd when almost stopped and pull away with little effort, I now need 2nd gear which, in my SM420, needs a new synchro. So for now I'm trying to anticipate so I don't get to a near complete stop situation.
First gear is still pretty much useless without a heavy load, but 2nd is still very comfortable for pulling away from a stop. I'd have to say that the SM420 and the 3:55 make a pretty nice combination... Pleasant 3-speed for general driving with an "extra" 1st when she's loaded up with cargo... nice pull-away power without the instant redline that you get with the 4:11.
All driving under 45 is profoundly different - truck is much more docile with noticeably less RPMs in all situations. I'm sure 55 will be acceptable with the 235 and my 15-inch wheels but I have a feeling that 16-inch wheels are in my future.
So, I can't advise you on the level of difficulty for the installation but I'm very happy with the results and once I get the rest of my drivetrain in order I'll be even happier.
