Join the relevant club and get the factory workshop manual. Like most pushrod engines it's pretty simple, all you need do is follow the set procedures to torque the head and return everything you remove to the right place. In fact engines don't get any simpler except for the complications due to steel bolts into aluminium. The skill comes in inspection and determining why the head gasket has failed. Tin gaskets are really robust and don't often simply just give up. You'll likely want to get the heads tested for cracks and for warping as well as a thorough visual inspection. Do your best also to check the linearity of the block too as well as cracks around waterways and pistons. Cleanliness and flatness is super essential with aluminium and the faxt tin gaskets have less "give" than other materials. If you are running 10.5:1, you could use a composite gasket which'll drop the CR to 9.9 or so - might help you if you want to run 95 unleaded. Best to sort the root problem though as tin should be fine.
One thing you might want to do if any work has been done before is check the lifter preload has been done correctly on reassembly. That procedure has been covered on this forum before. Depending on the mileage since last overhaul, while you have it apart you might want to replace the timing gear and even the cam, these are super, super cheap but removing the timing case can be a PITA (while this is off swap the rope seal for the modern, nitrile type!). It's a false economy not to do this unless you are 100% sure it was done very recently. Standard Rover timing gear starts to wear very quickly. Certainly it's best performance is finished within 50k. I didn't trust refitting the head bolts either and fitted new, not sure what others feel about this. I'm not that experienced, I erred on super cautious. I also had a friend who knows US engines very well. A case of beer might be a good investment...