Outdoor Power Equipment and Small Engines - Diffrence In Briggs Twin HP

I have two opposed Briggs Twin Engines. One is 16HP 401707 and the other is a Briggs made for Craftsman 14HP 400707.

Both engines have the same displacement (40ci) so, whats the diffrence in these engines HP ratings of 14 and 16HP??

Is my guess of valve size in the right direction?

Thanks in advance for you guy's insight.

God Bless,
Dave237

I'm thinking most of the differance is in the carb sizes & jetting. I don't think they changed cams or anything. Could be wrong, tho;)

The first 2 numbers on the code number gives you the year the engine was manufactured. Does either one have a red blower housing with the decal I/C on it? If their both alike than the difference is only the "Basic Series" (third #)
4010707 vs 4000707.
I/C stands for "Industial/Commercial". I/C engines have a steel cylinder sleeve,crankshaft bearings, and depending on the year, some have an oil pressure sensor, oil filter and the newer ones have a governer override system. Non I/C engines only have aluminum cylinders and plain bearings.
The 2 model numbers you gave indicate non I/C. So Basically they are the same electric start, vertical engines.:coffee:

It may also depend on when the rating was applied to the engine. Before or after it was installed in the application. Many are rated as manufactured, thereby producing a higher (sometimes much higher) 'rated' horsepower than they actually produce once applied. Push mowers are especially notorious for rating engines before installed.

Thanks guy's for your input. It's greatly appreciated!!

God Bless,
Dave237