Early prostock iron heads.

[Steve.k]

That could be Stan. I would imagine most the cams ground then were close. I know Paul said they had a terrible time with valves breaking. They were using the factory ford valve to start. Its apparent by repair work on head. He said trw sent him ti valves to try. They switched to those and life was a lot better.

[bob460]

That could be Stan. I would imagine most the cams ground then were close. I know Paul said they had a terrible time with valves breaking. They were using the factory ford valve to start. Its apparent by repair work on head. He said trw sent him ti valves to try. They switched to those and life was a lot better.

I thought you might like this Steve from Australia........click on pic and look at some cool old prostock parts pics that were for sale recently.

[Steve.k]

Wow very cool Bob460 thanks !!

[Walter R. Malik]

The heads I would like to see used or somewhat copied are the "Factory" Clevelands which used the criss-crossed pushrods. Just when they came out, the rules changed so, they never got much fanfare.

[piston guy]

Randy,
I ran a criss cross pushrod engine originally built by Mark DeGroff of Valley Head service. Mark custom made "rocker guides" ( not plates) because of the unique nature of the "pinched" rockers. He also modified the block for the additional head bolts needed ( 9x7/16ths +5 1/2") Crower ground the cam and it wasn't "perfect". I found two other sets over the years and there is a "long block" on display in a museum in one of the Carolinas. The head was a collaberation between Smokey Yunick and Al Buckmaster. According to Smokey it was "the good port" from a BB Chevy fitted into a Cleveland head. The head was good for 2hp/ci in NA dorm. I sold it to a Pantera guy and lost track of it.

[piston guy]

"In the day" GK( General Kinetics) had the field covered on cams with the "321D" profile and it's (IIRC) .472 lobe lift. Glidden didn't get along with Tewles (GK) so he went with Comp Cams to develop his own stuff.

[Steve.k]

I’ve seen the criss cross setup and it looked like severe angles in pics. Did they have trouble staying together?

[piston guy]

I’ve seen the criss cross setup and it looked like severe angles in pics. Did they have trouble staying together?

Steve,
Mark and I both ran the engine over ten with regularity. I never hurt a valvetrain part. "I" think Mark's innovative "rocker guides" were the major reason. Now days we would simply use Jessel or T&D that would locate in the "troughs" Ford cut into them instead of removing them. On a "normal" Cleveland the intake port in "on center" and curves toward the intake valve. This causes the air to have to bend again to go into the cylinder. The criss cross port is offset to be inline with the intake valve location ( like the "good" port on a BBC) resulting in less "turning" of the airflow. With 400+ inches the head would have easily made over 900 , FORTY years ago.

[Steve.k]

Wow that’s impressive numbers to say the least. So ten sets of those were built?

[Steve.k]

I’ve seen the criss cross setup and it looked like severe angles in pics. Did they have trouble staying together?

Steve,
Mark and I both ran the engine over ten with regularity. I never hurt a valvetrain part. "I" think Mark's innovative "rocker guides" were the major reason. Now days we would simply use Jessel or T&D that would locate in the "troughs" Ford cut into them instead of removing them. On a "normal" Cleveland the intake port in "on center" and curves toward the intake valve. This causes the air to have to bend again to go into the cylinder. The criss cross port is offset to be inline with the intake valve location ( like the "good" port on a BBC) resulting in less "turning" of the airflow. With 400+ inches the head would have easily made over 900 , FORTY years ago.

Would you have any old pics of these heads? And or engine? This stuff intrigues me to no end. It amazes me how ahead of the curve this stuff was and how those guys could figure out the architecture then. Very little cad programs then. Very cool in my eyes. I send alot of info to DragBoss Tim for his videos. Thanks

[piston guy]

Buy a Mustang Illustrated magazine , Fall '87 issue. There are some detailed engine photos in the article inside. The text is not correct but the pictures are excellent.

[Steve.k]

Might tough to find. I’ll go through my crates lol.

[piston guy]

Wow that’s impressive numbers to say the least. So ten sets of those were built?

"Possibly"

[piston guy]

Might tough to find. I’ll go through my crates lol.

If you can't find one I have an extra copy or two. My second magazine cover.