Just got a Winfield head, questions

Vanspeed

Vanspeed

Well-known member
Just picked up a new 6:1 winfield head from reds headers, I have heard that they bolt on but some said I have to check if the pistons don't hit. Is this true? Why would somebody sell a head that they say is a bolt on if it might not be?
 
I think it just depends on how much your pistons pop-up or not over the top of the block. If the block had been decked over the years then you would need to have what they call a "fly-cut" cut into the head to keep the pistons from hitting the head as they come up. If the block hasn't been decked then you might be able to get by with out having that done since the head gasket will provide some space.
 
If your pistons pop up above the block, you do not need to flycut the head. Much easier and cheaper is to have a machinist cut the amount of the pop up off the top of the pistons. They are plenty thick enough to handle it. I cut .025 off mine (7:1) and no problem. The Best gasket torques down to about .050 thickness which is fine. If it is a true Winfield, you do not want to mess up the crows foot design of the chamber.
 
I believe that the pistons originally popped up just a bit over .030. I believe that the copper clad Fel Pro torques down to about .060. and the composition B style gasket is MUCH LESS That would give less than .030 clearance if the block has never been decked. When the engine warms up this figure will decrease. when the rpms increase the bearing clearance can also effect the equasion. It is my belief that you actually need around .060 clearance between the top of the piston and the head, when the head is torqued down. With normal original pop up I would be afraid to run with less than .030 counterbore in the head. It may run ok with less clearance until it warms up but when rpm increases it could be hammering the hell out of the head.

If you have the head flycut the c.r. will decrease considerably. What PC/SR says about milling the pistons will be your best bet but will be a major operation. I have often wondered WHY anybody makes a head without a counterbore. Lots of people do run them, maybe sombody that is running one will chime in and tell what they did and how much their pistons popped up. Good luck.
 
Yeah I am looking for someone that is running one and what they did. My engine is atill all together and running so I do not know if it has been rebuilt/decked/whatever. I do not know what pistons are in it, originals or aftermarket so I guess I won't know until I open it up. I also do not want to take all the pistons out of the engine.
 
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