Marx3

Hi, I notice a difference in the design of the rockers and brackets between older heads and "newer" 4A heads.
Is it possible to take the whole rocker setup from an 4A head and bolt it on a #7 head or a B head?

Octania

#7 yes
A and #2 heads are 1965 issue, and they use a single year only different rocker setup with studs that have I believe 3/8" thread into the heads. All other heads 1966+ [B-Ka and #3-on] should be able to use the same rockers.

Marx3

so even though the setup looks different between #7 and 4A, they should interchange?
I am not sure what they are called, girdles maybe? the bracket-thing that holds both rockers down with two bolts are different on the 4A head than on the #7 head.

olds 307 and 403

Keep in mind if you mill the heads a lot, your lifter preload will be too tight with factory length pushrods. Just mentioning it, goes with your other thread.

joe_padavano

It's called a bridge and there are two designs, the three-piece design (two die cast trunnions with a stamped sheet metal bridge) and the one-piece design (trunnions and bridge in one die-cast piece). As Chris noted, other than the 1965-unique parts that fit the 3/8" studs, all are interchangeable.

Marx3

ahh a bridge, thanks :-)
Okay, which is the 4A design then?

joe_padavano

Should be the one-piece die cast design.

Marx3

ok. Thanks!