351 4v heads

[Keith Williams]

hello anyone know why this was done , lead to reduce chamber size thank you pros and cons

 

[turtle5353]

Possibly port match the intake they were using. We did that to my old heads.

 

[Spike Morelli]

The reason for the filling of the floor is to increase port velocity. Ford had been in the habit of making their cylinder head ports too small, or too large, from the factory, for performance street use. The factory port was designed for high RPM use, although a bit on the overkill side of things. Many cylinder head shops have for years, been modifying Ford's 4V heads like that. If you take a look at many of the aftermarket cylinder heads for Fords you will see that the intake ports are smaller than the factory ports. Back when guys like Bob Glidden was using the Cleveland engine, the entire exhaust port was machined away back to the valve cover surface, and "port-plates" were attached to the Cleveland heads to raise the suffering cleveland exhaust ports, and most had flat floors, or, "D-Ports". The "Port-Plate" modification on the exhaust side is outlined in many Ford performance information booklets. But, today, new aluminum heads are designed to flow better out of the box on both sides, Int and Exh.

 

[Keith Williams]

The reason for the filling of the floor is to increase port velocity. Ford had been in the habit of making their cylinder head ports too small, or too large, from the factory, for performance street use. The factory port was designed for high RPM use, although a bit on the overkill side of things. Many cylinder head shops have for years, been modifying Ford's 4V heads like that. If you take a look at many of the aftermarket cylinder heads for Fords you will see that the intake ports are smaller than the factory ports. Back when guys like Bob Glidden was using the Cleveland engine, the entire exhaust port was machined away back to the valve cover surface, and "port-plates" were attached to the Cleveland heads to raise the suffering cleveland exhaust ports, and most had flat floors, or, "D-Ports". The "Port-Plate" modification on the exhaust side is outlined in many Ford performance information booklets. But, today, new aluminum heads are designed to flow better out of the box on both sides, Int and Exh.

thank you for the info spike

 

[TommyK]

Not sure I would run those as is. It would be a bad day if a piece of that old epoxy breaks off and gets sucked into a cylinder.

 

[Keith Williams]

Possibly port match the intake they were using. We did that to my old heads.

thank you

Not sure I would run those as is. It would be a bad day if a piece of that old epoxy breaks off and gets sucked into a cylinder.

its lead has a screw i put back to the factory way