what is the hours that you should freshn up the 500 hp carb year 2000, ive done the valve springe at 250 hours change the oil every 20 hours w/ royal purple race 51 and they still run great im aproaching 300 hours.

thanks 32 thunder rick

How is your performance? Still up there as when you got the motors? Oil consumption? Do any of the plugs look terrible compared to the others?

every thing still is perfect, just wondering if at a certain hour you should rebuild.

My guess is that you're going to get a range of responses to your question. It also depends on what one means by a rebuild. Some folks will refreshen a motor by changing valve springs, lifters,etc. and later do a complete rebuild. Sounds like you've taken excellent care of your motors and they are running well. Have you checked compression and leakdown? They will tell you a lot about the overall condition of your motors. You changed valve springs which was wise. You might take a look at the wear on the rocker arms this winter and maybe change the lifters. Just an opinion, but those motors could probably go 500 hours before a total rebuild. As I said, you'll get a variety of opinions. I posed the same question as yours to one of the technicians at Sterling a few years ago and he chuckled and said that some guys are back at 50 hours screaming for a rebuild and others with the same motor will say they've seen no falloff at 200 hours. Obviously all engine builders have a recommended schedule for the upkeep of their motors. You're not running a blower so fatigue cracks with the pistons shouldn't be a concern right now nor are you running a long stroke where you'd want to keep an eye on the crank. Just my $.02--Lou