bgsengine wrote:pretty much would start with bore measurement to determine the base model series , then follow the model number reference guide to get a rough idea.. then you might be able to measure crank and compare to crankshaft drawings to come up with a crank part number,and a fitment search to narrow it down to model-type, from there, you can probably use that for parts lookups until you hit on a part that fits only one type number, that is used on your engine, and voila..
Other than that no way I know of to positively identify from anything on the block.. except you can know it is somewhere between 400000 to 440000 model series probably
I suspected what you indicate, was hoping might be some type of ID numbers on the block or ??.
A was given a opposed twin engine with no air cowling and no carb.
When I started testing the engine the #1 cylinder has 90-100#'s and number #2 35 lbs and leak down test indicated valves ok but leakage past piston/rings.
I removed the 42-2 head and the cylinder bore indicated a slight rust but nothing major so I suspect rings may be stuck from some water getting into the cylinder. I'll check the bore size and try to get a match up for rings, head gasket and sump gasket if bore with-in specs by using a spec chart you indicated.
I've noticed that several of the Briggs opposed twin engines have
same model numbers but Hp's vary by several HP's going by the Briggs
glued on decals