Office of Steam Forum for Model & Toy Steam Gas & Hot Air Engines

Why not just aim for a used for your "Big Block" conversion?

Would save you quite a few bucks for parts 

I just stubled on this, which doesn´t look bad to me:
https://www.ebay.com/itm/WILESCO-STEAM-TRACTOR-APPEARS-NEW-AND-UNUSED-MADE-IN-W-GERMANY-VINTAGE-TOY/133698304020
Furthermore has the advantage of being old enough, to have a "real" steamvalve on there.

Wow, that is about 1/2 the cost of a kit...I will put it in my watch list and see what happens near the end of auction. Thank You!