rcdynamic88

I was looking at replacing the original rocker arms with a set of the Comp Cams part number 1242-16. The description reads as follows:

"These COMP Cams® High Energy™ Steel Rocker Arms with a pedestal mount and 1.6 ratio are designed for 1967-79 Oldsmobile 260-455 applications. Engineered to help eliminate the noise and slop associated with older worn and high mileage stock rocker arms, High Energy™ Rockers feature a long slot for higher than stock lift camshafts, these rocker arms are an excellent replacement choice for engine rebuilds using either stock or High Energy Camshafts™."

OK, so won't these also fit a 1965 or 1966 330? Would the only exception be the 1964 330 with the shaft type rocker arm arrangement? Its not only the Comp Cam versions that don't include the 65-66 versions. I have looked at this same fitment description for some "stock replacement" rocker arms listed on eBay, and they also only include the 67-79 260-455 engines.

What part number do you guys buy when you just want some new "stock" type rockers and bridges? Sealed Power?

oldcutlass

The part numbers for the Melling kits and others are the same for 65 and 67.

These are the over the counter kits available through OReilly:

http://www.oreillyauto.com/site/c/se...Redirect=02264

I see no reason for you not to use the comp cams kit, plus the price is less expensive:

http://www.summitracing.com/parts/cca-1242-16/overview/

rcdynamic88

These Comp Cam Rocker Arms don't fit! The rocker arm studs on my heads are a 3/8 and the rocker arm "pivots" only have a 5/16 clearance hole. What size are these rocker studs supposed to be? Maybe this is why they weren't listed? I even contacted Comp Cams and they said they would be fine. Perhaps I can get the correct size studs and still use the Comp Cam rockers. My stock rockers show wear on the part that contacts the valve stem, and the spot where the push rod sits is also worn. Do later model small block Olds heads have a different size stud than whats on these no. 2 heads?

olds 307 and 403

Yes. The 66 and later use 5/16" bolts to hold down the rockers and therefore use different rockers. Olds did funny things with their valve train, this one of them.

rcdynamic88

Do you think I can install the later model studs and make these work?

rcdynamic88

So I have found out through a couple of sources that the 1965 #2 heads have a different rocker arm set up that uses 3/8" studs instead of 5/16" bolts. The rocker arms themselves look the same, but the way the pivot part of the rocker is "located" on the pedestal/stud is not the same.
I also found that Rocket Racing offers a complete adjustable rocker arm kit for the #2 SBO(and A casting BBO) heads. It comes with studs, guideplates, roller tip rockers, and pushrods. No machining is needed, it uses the fact that the heads have a 3/8-16 threaded hole for a stud already. They have the quideplates and studs to fit in the existing holes. Its probably a case of overkill since I'm using the original cam, but "new" stock type replacement parts for this single year application are hard to find. It will be a "piece of mind" addition to this rebuild to have an updated adjustable valvetrain with new parts.

olds 307 and 403

You can get 3/8 to 5/16 studs.