Reply to "4V CC head porting with pressed bronze valve guides."

I'm talking about the bronze guide picture that George posted. If you look at the bronze guide the porter has tapered it.

I have completely removed all remains of the iron casting in Windsor heads and pressed these guides in. So far so good. Those bowls are so small, you need to do whatever you can to increase volume of the ports on them.

With roller tipped rocker arms the lateral loading on the stems is reduced so I am not seeing oval shaped wear or splitting of the guides...so far.

My A3 heads have NO remains of the "bump" in them and strictly run on the bronze guides.

The aluminum Ford racing heads I am sure differ somewhat from the iron heads but I'm not about to cut one apart to find out.

Just think of it this way, the valve stem needs support. If you keep removing it, at some point it won't have enough. Probably the bronze guide will split.

Why chance weakening the bronze guides. Don't shorten them or reduce their outside diameter.



I would follow the old Ford diagram of unshrouding the valves a little near the seats.

If you want more, then you notch the top of the block like the 427 Ford blocks do.


If you want to seriously unshroud them then you must use smaller valve diameters. Probably 2.08 or 2.09. There you could leave the ring in place.

To do that you probably will need to install valve seats to raise the valve back up to where it should be.


The C302B aluminum heads are running smaller valves both intake and exhaust and make up flow with more velocity.

That setup does change the character of the engine but who can argue with 700hp?