Depending on the miles, now would be the time to do valves and valve guides...........and possibly prechambers.

I did this on the SD.......to the tune of about $900.........and I'm very satisfied with the results. The SD had 180K on the clock and it was definitely in need of new exhaust valves and guides and seals.

Naturally, if money is a factor, you can run it as original for 300K, but the improved starting performance is significant.

If the engine was maintained to any degree, I'd advise against going into the lower end.........very costly and not at all necessary.