Looks like a 1720 to me also, but not the chrome emblem you describe.
it is worth maybe $20 if you need a few parts, if it has a magnum twin and a deck.
The deck spindles are the tapered bearing type and are replacements for the "water pump type"
the starter and magneto coil are worth a few dollars also.
Cylinder heads worth a few bucks.
it is a vertical engine so not interchangeable with a horizontal for practical reasons.
And yes it is a MTD lawnmower not a garden tractor and a poor transaxle.
The gas you burn to get it is worth more than it is.
Sorry to piss in yer porridge but we all have done something similar
