My experience with all the Magnums I’ve bought… the Cam bearings are shot!!!
With a 200k on it… more than likely a cam lobe is worn also!
Crosshatching in the cylinders will more than likely still be visible!
You didn’t say what the plugs look like… so assuming little to no oil on them will be a good sign… if there’s oil on all of them… then more than likely it’s got the notorious plenum gasket fail!
You can hillbilly overhaul it and it will more than likely run fine… you can get kits on eBay for less than $300 for a basic overhaul or you get a master kit like this one throw it together and head on down the road
[URL]https://www.ebay.com/itm/277076654613[/URL]