on a 69 mustang, 351. the rusted headers were taken off for replacement. what was found was exhaust port blocker gaskets. they blocked about 1/3 of the port. i have never heard of these. whats the point ?
It must have a '70 or later Cleveland engine instead of the 351W that came in '69. I've never seen them on a set of Windsor heads., they usually are too restricted already. BUT.. it was and still is a common practice on Cleveland heads to help speed up flow because the lower part of the port slows the flow and creates a deficiency. The "power plates" were not around originally.. they used to mill the edge of the head/exhaust port off and put machined aluminum plates on it that were held by the outer head bolts and then port them together. It was always a port about half the size of the factory port and higher, increasing flow enormously and was standard fare in Pro Stock for many years. It was an expensive procedure for the average guy and stainless exhaust "power plates" were developed with a tongue that goes into the port effectively changing the size and giving some of the benefits of more expensive aluminum port plates with no machining. I think there are more than one made now and not all are stainless.
Is your motor a windsor or a cleveland? If it is a cleveland, which heads, 2V or 4V?
I never heard of anything like that for a windsor. (I do know of the port plates for the Cleveland, I never heard of them being used in a car with shock towers because of the severe bends required in the headers to exit down.)
If it is a 351Cleveland,(which like woods said, were not installed in any 69s that I know of),could those exhaust gaskets be 2V gaskets on a 4V head?
There is a definate difference in the size and shape of the 2v to the 4V exhaust ports. I know that they usually leak like crazy if you put a set of 2V headers on a 4V head. Or use the wrong gaskets. I know this from personal experience.
A picture of what you have and a positive motor ID would be helpful.
Kultulz to the rescue :thumbup:
Those plates look kind of neat, I wonder if they work.
I was thinking about some of the Parker intake port stuffers for the Cleveland I'm building right now, but they are a pain because you need to fill the floor of the intake runners with epoxy to match. ( it probably wouldn't be a bad idea to do the same for those plates though)
I never knew they made anything out of sheet metal for the exhaust side. ( I remember the ones that were about 1' thick and the head was machined with a ledge for them to sit on)
I wonder if there is any real gain from the exhaust restrictor plates?
i'm not a ford guy. so i couldn't tell ya. i can get pics though, if there is room to get the camera in there. its not my car, its a friend of a friend thing. i guess he just bought the car. how do i tell if its a C or a W ? will the pics tell ? if so, what do you want pics of ? i can get the pics on monday.
They worked Mike as they were actually dyno-tested back when they were popular. They actually snap in as to raise the port floors. On the exhaust side, they were more of use raising the floor due to FORD exhaust runners being squeezed by need of them fitting into the uniboby chassis and fitting exhaust manifolds to them (same on 385 Series).
I had a 73 RANCHERO with the 351CJ and that thing ran like a scalded ape (it was bone stock).