So I have a 500efi with 330 hrs, oil changed every 25hrs, runs great, still has great power do the springs need replacing or is that just the 500hp

I don't know what the manual indicates....but you've got some time on it....its not that expensive and it would be good for a mechanic to inspect the rest of the valve train....maybe catch something that is wearing.....maybe ya get another 330hrs out of it.

Agreed better to spend a bit now checking than risk a larger failure 250 hours seems to be the median check point.

UD

Should I do the springs or pull the head and do a valve job too. 330 hrs seem low to me, I am going to do a leak down test on it first. I just hate to open something that runs so good

I would start with springs and see what the inspection shows.... a "qualified" engine builder can give you a better idea then this forum. Its a great motor....

Id do a leak down and see whats up, it will tell you if the valves and rings are sealing, if that good then Id leave em on and change the springs

I would also do lifters at the same time we have had a couple of failures at 300 to 350 on the 525s

And boy do I understand that feeling sir. Makes me cringe every time.

if you have a good guy - if the mill really is all good it wont cost much - and if it really isn't then you'll be better off.

UD

Well heads are done at machine shop, no valves or seats bad, all guides are good, old springs were all in spec, installed new anyway, old head gaskets looked good, guess I would have been ok