A broad, but fairly straightforward question. Theoretically speaking, lets say I have the choice between a run of the mill L/PL Twenty versus a comparable PV Fifteen. Both are in average inoperable unrestored condition with the usual missing parts here and there, manifolds needing attention, undercarriages are mediocre, but engines are free etc.

If I was interested in doing a thorough nut and bolt restoration on one of these tractors myself (well equipped shop), could I expect one to be notably more expensive than the other? Or would they be pretty comparable cost wise all things considered? I'm guessing that used and reproduction parts availability for the engines, undercarriage, and commonly missing components is probably an important factor in this as it drives a lot of the associated cost.

Pictures attached of me dragging home a very tired PV Fifteen.

When I first saw the pics I saw the Rover in the background n thought you were over in OZ Land, lol

I hear what you're saying. I do have a little preference for the Twenty and obviously it also has more historic significance from a model standpoint than the Fifteen. At least nobody has hopped on here to say that one is clearly more difficult/expensive to source parts for than the other.

Part of this equation I'm sure is location as well. I'm in the south central Pennsylvania area. I already have the PV Fifteen in the pictures. In areas of the country where these tractors are more common, it would probably be considered a parts unit due to the number of small parts missing or need to be replaced. But pickings are slim in this area for projects and parts. If I wanted a Twenty it seems like it would require me to drive halfway across the country. Pros and cons I suppose.

Aumann Auctions has a sale ending in Ohio in about a week with several 20's on it it a few configurations.

I understand what You trying to Do, been there doing That .Both are interesting Units Machines ., lets look at it this way, the Twenty is the First Tractor designed and Built the Company that formerly Holt and Best. The twenty is basically a smaller Version of the Thirty that Best produced many parts fit both, [Rollers , tracks less a link front Idlers etc] ,many alterations were made as Time went on ,Particularly Gearbox ,which a cow to work on, , I have had to Get engine Bearing rabbited and crank ground to match and Line Bored [very expensive Operation [, incidentally Engine valves are same as a Twenty Two]. with only 6319 made is Rarer that the PV 15 with about 6500 made. The fifteen is much easier to find parts for as they 'Basically" follow through to the Small Twenty, Twenty two etc. Even though though the Tracks same Measurement right through even to the D2.,and You can still get some l parts from Cat . the worst part of the Fifteen is the Carb, a mongrel to praise it up ! I find it better to work on a couple Units, other wise while waiting for Parts or services to come Good Time is wasted ,Remember that the the Twenty should be Painted Grey and Likewise the Fifteen except for the Last Couple Hundred were Yellow., Good luck with what You decide and Keep us Posted. LJ

I don't know if this will help with your decission but the big twenty uses the same tracks as the cat 30 and the big 15 is the same as the cat 22, not sure if the roller mounting is the same, hope this helps