I have a bad valve guide on one of my head. My machinist is going to see if he can replace the guide and go through the heads.

He is recommending that I change all the valves. I have Incinal (sp?) exhaust and severe duty intake . they have about 130 hours on them.

The motor is a 454 with a 177 blower on it with an inter-cooler. I run it mostly at 4100 rpm . I never keep above 5000 rpm for more than a minute.

Is it time to change the valves or not ????

I thought I should get about 300 hours out of a set. Am I Wong????

I'm in process of building a spare motor for my boat and just went thru this exact same scenario. My old heads were merlins,they had 260 hours on them with manley inconel exhaust and there super duty intake valves. 4 seasons total on them between my 502 then my 540 with a light valve job done when switching the heads 2 years ago. I had 3 guides that were wasted,we replaced those 3 valves,the rest looked like new stem wise and cleaned up with very little grinding. I ran 5400 rpm's with them at wot and 8-10 lbs of boost but like anybody they seen more time at 3000-4000 rpm's. Unless they look bad I would only replace any that were wore and run them another 150 hours,300 hours under light to moderate conditions isn't that severe. You didn't have any signs ofwater reversion did you(rust in exhaust ports or cylinders),if you did that would be the only way I would change them at 130 hours,the cold water quenching them kills them,Smitty

If you do decide to change them, Ill buy the old ones as long as there straight. Thats all I use. Take outs.

Paul, the engine is out !! Replace anything you can. If he suggests it.. Do it !!