I saw a pic of a BBC setup and it had billit pieces of alum that fit together and bolted above the rockers. It totally covered the rockers and looked to be 1\2 inch thick . i was wondering if anyone could explain what these are and any further info about them.

Thanks

Its a stud girdle and it helps to stabilze the valve train.

So is that an example of what you need for a gen 4 to run roller drive train?

No such thing as Gen 4. There's Mk IV, then Gen 5 and Gen 6.
Most Gen 5 and all Gen 6 blocks are machined for the dogbone style retainer needed to run OEM style hydraulic roller lifters. If a Gen 5 block is not machined for them, it can be done easily enough.

Mk IV blocks are not machined for the dogbones, and they require a "retrofit style" hydraulic roller lifter with tie bars. They are more expensive than the OEM style dogbone lifters and also require different pushrods.

All you need to convert a Mk IV to a hydraulic roller setup, though, is a bronze distributor gear, a set of retrofit hydraulic roller lifters, matching pushrods, a hydraulic roller cam, and a cam button to keep it from walking back and forth in the block.

Stud girdles are not necessary. Roller rocker arms are not even necessary.
Usually, though, if you are converting to a hydraulic roller from hydraulic flat tappet, you want to upgrade the springs and add roller rocker arms too.

MC

Also, some hydraulic roller cams do not come with a fuel pump lobe. Be sure you choose accordingly.

Thanks Griff and Mc.

You guys are always ready with great help for us learning. It means a lot and not often enough said.

THANK YOU for your time and effort here.

Richard.

At what point is a stud girdle recommended? I'm running a .623 lift hydraulic roller cam with ISKY tool steel endurance springs, I think about 150lbs closed pressure, Pro Magnum roller rockers, with a 6000rpm redline.

I have .663 lift with Isky springs @150* on the seat and run a stud girdel. I think my next step will be shaft rockers.