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

Actually, I think I see what you are talking about, between the bolts is roughly 3 1/4 inches.

I am looking at a site called "CaryCompany".  What do you think of two of these (totaling 400 Watts).  Do you think they would be two short?

0.37" x 1.75" Swaged Cartridge Heater, 120V, 200W

Be sure the cartridges are buffered with extra metal to act as heat sinks

I don't think I follow this suggestion at all.