That's correct. The 54 and 60cc Poulans have a big crankcase that includes the tanks. There's a lot of cutting. The case is held together with screws that are fore - aft oriented. So, a mounting plate has to be made. They make a nice engine but it's a lot of work. If you have the work done, there's a guy on here that does a nice job for around $250+ range. It's not cheap but this includes the electronic battery ignition conversion.

The 60cc was discontinued in the previous century. I don't know if the 54 is still around? It was last year. They pretty much had the same case. There were many different models of these. My 60cc is a 3750 type II but later types were 54's.

Enjoy,

Jim