V10 which one with issues

The OP is looking for a manufacturing date where the spark plug problem was solved. Several postings have provided years when the problem was supposedly solved. My comment is that Ford made many many V10's and a very small number had problems. I have read many of those 2,335 cases at Consumer Affairs and it seems like it affected all Triton engines and has occurred even in a 2008. See Donald of Cincinnati, OH on March 21, 2015.

Even in older V10s the spark plug issue is not a huge one. Whether you get a Chevy or Ford, at any rate if you're looking at a 15 year old coach, the condition of the roof and body are more critical then mechanical components. A blown spark plug costs a few hundred to fix, a transmission about $3K, but a delaminated wall can cost more to fix then the rig is worth.

You could preclude some of these problems by looking for a Class C on a
Chevy Chassis.

My 26Q is short and with the bed in the rear.

There are some like theForesters that are only 24 Ft long and have a short Queen in the rear pop-out that may work for you.

I knew you guys would know about this! I copied the pics and put in a doc with the info and printed it out.
Thank you soooo much!

Slightly related: if you've got a 3v V10 (not available with regular Class Cs), be VERY careful when removing the spark plugs for the first time:

http://www.agcoauto.com/content/news/p2_articleid/120

Recommendation is to remove/replace your spark plugs ASAP with anti-seize on the extension to prevent the plug from freezing in place and breaking on removal.

applik wrote:
I've heard of 26' units, but just haven't seen any we could gut the back and put in a BIG bed.

My 28" Winnie (labeled 29 because they count the bumpers apparently)
has a "short" queen in the back but it looks like a bigger bed could go in sideways if the little closet was removed.

Of course, that would mean that one person would have to crawl OVER the other occupant if both sides were occupied.....or both would have to take a bathroom brake at about the same time.

The above is very accurate. The 1997-99 CHASSIS YEARS, with 275-HP are the ones with poor design, too few plug threads. CHASSIS YEAR 2000 and later are the "PI" heads (305-HP) with a plug hole design having adequate threads. Unfortunately, some heads, and that of course means thousands, of heads were made on a machining line that didn't get the holes quite lined up with the seats. It took a few years of production to sort that out. It has to do with which plant did the machining. I believe it's possible to tell from the VIN where the engine and apparently the heads came from. When we bought ours nearly 10 years ago, I found somebody who asked for the VIN. I think he checked with an engine remanufacturer, came back and said I should be OK. We went ahead with the deal. With 30,000 original miles, prev owner hadn't changed plugs. At 40,000 now, I don't plan to do it any time soon. But I can say there've been no issues.
From 1997 to the early 2000's, the transmission was called 4R100, gearshift button marked "OD Off". It was replaced somewhere around 2004 with 5R110, gearshift button marked "Tow/Haul". 4R100 is a good unit, no problem there, but the 5R110 has some new tricks. I mention this because if the Class C has "Tow/Haul" it is also new enough to be past the years with some problems in some of the PI heads.

An "01" should be OK, it might be an 01 or 00 chassis though.

Easiest way to tell for sure is to look for the "PI" stamp (with a mirror) on the passenger cylinder head above the front exhaust port:

Above the right-hand port in this pic you see the "PI":


Here is where it is in the engine bay of an F150 (similar, but V8):


After that, 2000+ (PI heads as noted in picture) still have a decent chance of being all right, but can still have problems due to improper machining of the spark plug threads (they increased the number of threads on PI heads, but they can still have problems). 03 or 04+ will be fine. 97-99 would be the ones to avoid, but fixing them can usually be done without tearing the engine down.