tyler72

Actually, yes the stock size heds do have 5/16 threads, but the earlier heads had 5/16 studs with nots instead of bolts. Im not sure about the 78 heads, they may be bolt or stud. Anyway, for the GT-40 heads, I KNOW they are 5/16 bolts, but if you want put in screw in studs for use with Roller Rockers, check online. Its either ARP, or Comp cams that makes screw in studs with a 5/16 thread on the bottom side (side that screws into the head) and a 3/8 on the top side (where the rocker goes). This prevents you from having to get machine work done to install the better rockers.

projectresto83

Cool. I will have to look into those.

tyler72

Yeah, they cost the same as any other screw in stud, but save time and money by eliminating the usually required machine work.

projectresto83

Yup I found them. I guess then with those I don't have to use the guide plates that are stock correct. Since there is no plave for them to sit anyway.

tyler72

Well, with roller rokers you will need to run some type of guideplate, otherwise, there will be nothing to keep the rockers in line with the valve. With the guidplates you will also need to be sure to use hardened pushrods. Do the heads have guideplates on them now???

projectresto83

Yea, they have the stock style channel iron shaped plates. (The ones that look like u's squared off) Where would that plate go then?
From this pic it doesn't look like that would work
http://store.summitracing.com/largei...ca-4504-16.jpg