Vanguard twin crankshaft interchangeability

[RMR]

Happy New year everyone. I'm hoping someone with some knowledge or available parts on the shelf to compare can help me determine some interchangeability of crankshafts. I am working on my personal JD Gator with a 16hp Vanguard. (Of course JD won't give you a Briggs model number to offer up) I also have a 21hp Vanguard sitting on the shelf that I'd like to swap in (Model 381447 0xx3-E1 [middle two numbers illegible] 00071011). The first obvious set back is the crankshafts. The Gator shaft is tapered where the 21hp is a standard straight keyed shaft.
This is where I need help. anyone know if the internal specs are the same? ie: stroke, journal diameter and width, etc... I can and plan to open them up to compare before I swap the 16hp into the 21, but was hoping I could get a little light shed before I take it that far.

Thanks
Chad

[SUKI]

What is the model and serial number of the Gator?

[RMR]

mod. 550 S4 XUV ser. 1M0550FBKEM030925

[KE4AVB]

That Gator has either the 355447-0118-01 or 355447-0121-01( 16 HP). And according to Briggs Power Portal there are two crankshafts in those engine and none of the 381447-0??3 crankshaft PNs match either one.

[RMR]

Thanks KE4AVB. I knew the P/N's would not match since the Gator has a tapered shaft. I'll use those model numbers you supplied and see if the rod's use the same part number. If they do, there is a good chance the internal dimensions are the same.

Chad

[KE4AVB]

Here is some of the crankshaft specs. It seems the crankshaft will same within the same date code range internal to engine.

Crankshaft
Crankpin 1.4567 – 1.458 (37.00 – 37.03) Reject 1.455 (36.95)
Magneto Journal
Before 9705010 1.180 – 1.181 (29.98 – 30.00) Reject 1.179 (29.94)
After 97043000 1.376 – 1.378 (34.95 – 35.00) Reject 1.376 (34.95)
PTO Journal 1.3 76 – 1.377 (34.95 – 34.98) Reject 1.375 (34.92)
Throw 1.376 - 1.380 in. (34.96 - 35.04 mm)

[RMR]

And thank you again for those specs. Are those for the JD engine or the 21hp donor?

[KE4AVB]

That was for both engine series from the Vanguard Twin service manual.