Hey guys I'm trying to figure out what you guys think I should do here. I have been F/I for a while my block got screwed i think bad berring or something, I am getting a f22 block with 15k miles on it to replace it. I still have the same head and I dont think there is anything wrong with the head but I haven't taken it apart yet. I'm trying to figure out if i need to do anything to the head and what exactly I need to to when putting a f20 head on a f22 block. I am going to be shooting for about 400-450 hp when I get everything done.

 

new valves, guides, seats, ap2 retainers, get it checked for straightness...

some have had bad expereience with stock valves breaking. search for the valves, i think supertech, theres a thread with the valves and the source to get a deal on them.

 

with that mileage you will probably need new guides, but at the least inconel valves exh side, ap2 retainers, and a decking.

 

So new guides, valves and retainers should do? Will the Brian crower retainers work fine? And is it something that anyone can put in or does a shop have to do it?

 

Its best to have a reputable machine shop do the work. There is a lot involved with setting up new valves and things.

 

you said a bearing problem? make sure the head was not starved of oil from low oil pressure...check the cams and cam caps for scoring.

other than that i wouldn't bother rebuilding the head for a stock bottom end, but thats just me.

 

If You're going to have the head off anyway, You might as well have it gone through now, as opposed to having to remove it later if something comes up.

 

With the mileage the head has, I would take it to a machine shop and have them resurface the deck, check the valve seats, hot tank it and look for any other problems.

Next I would replace the guides, valves and retainers at minimum. If you are going that far I would also want look at replacing the springs.

The reason we are recommending valves is that you will have a good chance of warping the exhaust valves and possible the intake though that is more rare. I would be very surprised if you do not have a bent intake valve with that many miles anyway. Oh, and if you are buying new valves Inconel is the only ones that are fool proof, it's a crap shoot with standard Stainless valves.


Good luck, once you go boost you never go back.

 

It's in the wrong order.
To check the seats before changing the guides doesn't make sense.
If the guides are changed the valve seats must be reworked! The guides and the seats must fit the angle within a very close tolerance.

And valves and guides should be from the same manufacturer because the material pairing is tricky.

Supertech is a good recommendation!

 

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listen to this man.............very good advice