YS4500 engine swap 21hp Intek OHV to 24hp V-Twin B&S

Hey everyone, I am pretty new to the forums and was looking for some guidance on the engine swap I will be doing. Last summer my dad gave me his Craftsman YS4500 with the 21HP Intek Plus OHV motor. At the end of the summer while dumping my last bag of grass I shut it off and when I came back to it about 15minutes later it started and then I heard a pop and the mower shut off. I recently had the time to take the motor apart hoping it was just the rod that broke. No such luck, the Rod, camshaft and crankshaft are all shot. Replacement parts would be roughly $350 which I might as well buy a used mower for that price.

While searching for a used mower I found a B&S 24HP Intek V-Twin a guy was selling for $50. He stated it stopped running because he took it to a mechanic for a valve adjustment and the mechanic messed it up. Well I go look at the motor, check the spacing on the valves and all seems good. I keep looking over the engine and notice the guy has the throttle cable and the choke cable switched... I gave him the $50 he let me start taking the motor off the mower and before I started I switched the cables and it started right up.

So, I now have a 24HP Intek V-twin that I want to install on my YS4500 mower... does anyone have experience doing this? If so any tips or recommendations? The shaft size is the same and the muffler should fit as well. Any help on this would be greatly appreciated

Brigs to brigs everything should fit just fine.

Even though I'm going from a single cylinder to a V-twin?

Throttle n choke cables may be different. But the wiring should plug n play

The throttle and choke on my single cylinder motor was the same lever. All the way up was choke, all the way down was turtle speed. Will it still work if the choke was separate on the previous motor or will I have to add in a choke cable?

You will have to get a cable.
Nothing fancy, an old throttle cable will work just fine or a choke cable.
It will most likely be a lot cheaper to buy a universal cable & fit it.
You cut the outer to length then slip the inner back in. hooked up at the operator end then cut the inner & make a Z bend in it