If that's the Richard Daoust VJ Monitor then it was 1/3rd Scale. I don't think the company you mention has actually cast any sets from the patterns they got from Daoust but they did purchase a few remaining sets of castings as part of the inventory. I got one of the Bronze sets at that time but won't be parting with it. Not sure if they are even advertising the engine at the moment as website has been unobtainable for a while, they do have an e-bay store but not much in it.
Minicastings is an eBay dealer that made the Monitor PJ, scale of the 1 1\4 hp pump jack. I think they were brass. He also had a 3/8 scale of a 2 hp. And he is in Ohio.
Then there was Pacific Model Design who had a 1/3 scale of a 4 hp. He had some really nice kits of several engines. Unfortunately he has a situation and is not selling kits any more.
I also have a pattern set that is 1/3 scale of the 6-7 hp. But it needs lots of work yet. Maybe next year. I doubt you seen it, but it has been seen a bit.