...because they know more about the Cleveland family of engine. Having said that: The hose coming from the duct valve motor connects to one of the two ports on a bi-metal switch connected to the underside of the air cleaner near the carb.

Shoe.

Jim,

I like the C6AE-R because it can be used with stock exhaust manifolds in a unit body car. In a Galaxie or earlier full size Ford or Mercury I can install four header bolts per port, making leaks nearly impossible.

Royce Peterson

Since Ford apparently used the same patterns for the outside of the block from 1966-on, and stuffed the molds with mission-specific cores, the actual block can only be identified with dimension checks and a search for other markings.

You've most likely got a 390/410 car block, but it might be a 352, 428, 330FT, or 361/391FT. Checking the water gap between cylinders (or looking for a displacement number cast inside the water jacket) is a good way to narrow-down the intended application. Also, if the cranksaddle webs are the reinforced style, you can increase the probability of guessing the correct application. Markings on the flywheel surface (if any exist) can sometimes identify an engine block to a high-degree of probability, though don't be surprised to find a 427 sideoiler fanny misplaced onto an otherwise non-performance FE block casting - Ford apparently did this a lot.

Rumors also claim that an "X" in the lifter galley means the block might have about 1.75% nickel and maybe a half percent of chrome added (probably with a slight reduction of silicon) to make it a little more impact resistant, though possibly at the cost of some tensile strength. If someone in the foundry converted the "X" in the galley into a snowflake, it's just another reuse of a performance marking in a non-performance situation.

What markings are on the rear of the block? Can any numbers be seen inside the water jacket area?

Shoe.

Put simply, an engine is only an air pump. The more air that can go into the cylinder will make that much more power. Every little bit helps.

However, port shape has as much to do with it as size. Air doesn't like to turn corners, so big ports with a dog leg are virually useless (look at a 429CJ or 351C-4V exhaust port for extreme examples).

Ford's intake ports are historically very good. The weakness is on the exhaust side. It's not that the engineers didn't know what they were doing. The problem was the chassis configuration. The use of a spring on top of the control arm lead to narrow engine compartments. This lead to limitations for the exit angle of the exhaust port. In turn, this lead to the unbalanced heads we have to deal with -- much more intake flow than exhaust. FYI, unbalanced means that the exhaust flow is less than ~85% of the intake flow.

I'll stop now as I could go on for about an hour, but that would bore everybody.

Cheers,
Dan

prolly 10 .5 to one

If the lifters are new or oil free it's fairly easy to set the clearance with a channel locks, if there loaded with oil find or make a tool . This is a very important operatioms of the build, this will correction some maching height problems that you might incur. I have found that some of the new replacement lifters are also a problem, they don't have enough built in clearance or plunger travel. If you think you have a 0.100" of room you don't. Keep the clearance to work with at 0.030 on the low side and no more than 0.100 of clearance on the high side, which means you only have .070 to work with your push rods. Ray

You have to make sure your at the back side of the of the cam not on the lobe!. Rotate the engine untill the rocker comes off the lobe, and then give it another half a turn more, and then check your clearance.

list the tag and well help you decode it...
Henry Edsel Ford

I had virtually the same problem. I milled my rocker stands .050" and used the stock length pushrods to correct it. This also moved the rocker tips closer to the middle at mid travel and centered the pushrods in the manifold holes. Look at where the rocker tip is and decide if this will work for you. If the geometry is correct the rocker sweeps across the center of the valve at mid lift. This will also avoid any problem with pushrods rubbing the intake.

Royce Peterson

Made only a couple of years for NASCAR. It was the last head design for the 427 until the BOSS 429 was ready.

The push rod goes right through the intake port, strickly high RPM ( about 7000 for NASCAR).

Ford made a 302 version in 68, but the power band was too high for Trans-Am racing and were replaced by the BOSS 302 in 69.

The exhaust port mods greatly reduces their value.