Quote Originally Posted by FamilyTimeRV View Post
Thanks for all your efforts and information. We're looking to add an affordable way to rv with 4 children. The FMC (possibly GMC) is our choice with an efficient power plant. We may follow your example.

Kevin H
still in planning & prep stages
Kevin:

Just a few thoughts. I am going through the same thought process as you are. Mind you, I don't have to factor in 4 kids.

Currently I am leaning towards the GMC. The original design was not only brilliant but it has survived the test of time with a large and active owners community. Having said that, for your purposes, shoehorning yourself, significant other and four kids into a GMC would be tough with any of the available floorplans.

Additionally, the front drive system comes out of the Olds Toronado/Cadillac Eldorado of the same vintage. Without major surgery, that means you are stuck with the THM 425 transmission (basically a 400 with the torque convertor and front pump attached to the engine with a chaindrive to the rest of the tranny turned around and going forward. Still a great transmission, especially if you can find a "switch pitch" trans from a 67 or 68 car. Essentially gives you a 6 speed tranny.

The bell housing is a "BOP" bolt pattern so if you use any other engine you would have to get an adapter plate, modify the engine oil pan to accommodate the right hand drive axle and fabricate a front mounted engine mount. There are a number of 6.5 turbo conversions out there as well as a couple of Duramax conversions.

If you are still interested in the GMC, I would suggest you look into the GMC Co-op in Orlando Florida. Jim Bounds is the by far the most knowledgeable person in the community.

http://www.firefightmarine.com/gmccoop/

This thread has me looking at the FMC as an alternative. Love the concept of the independent rear suspension and pusher engine layout. This plus the added room for the family would make sense for your uses and open up your options for engine trans combinations. Unfortunately they are not only the same vintage as the GMC but there were far fewer manufactured. I would question the availability of parts, specific to this platform.

I have also started looking at the Airstream Motorhomes. Lots of them out there with a 40 year production run including some pusher versions later on. Even today, they are still manufacturing a motorhome based on the Mercedes Sprinter platform. Still trying to get some information on the various versions and separating the good from the bad.

From a cost point of view, I would seriously analyse how you are going to use this motorhome and specifically, how much you are going to use it. Upgrading any of the powerplants in these vehicles to a newer engine is far easier and cheaper with a gas conversion than the diesel. In other words, you are going to have to pack on lots of miles to justify a diesel conversion from a cost point of view.

The new "LS" series GM gas engines are plentiful, with an extensive aftermarket support system in place. Properly configured, they can be programmed for very acceptable fuel consumption and with reasonably inexpensive "go fast" parts can lay down some very respectable power. Based upon my research into the GMC, I could do an LS conversion for about $5,000 less than any decent diesel conversion, plus, it can be fixed on the road by any reasonably equipped garage. Even Bubba in lower Buttkiss is probably conversant with this engine family.

Myself, I am leaning towards a GMC with either an AMG 6.5 or LS engine and a switch pitch transmission, upgraded suspension and brakes and a total re-working of the body. I expect the cost to be in the 30 grand area, including the initial purchase. Not much more than a reasonable tow behind trailer.

Hope this helps.

Bill