Roller tip rocker arms for AMC?

Go here http://store.summitracing.com/part.asp?ssid=U8BQ7O5DMJMQKDL47EYWL3HQTH&part=2D25B8CB-3630-11D3-949D-080009FC5B5F
These require the guide plates and screw in studs .....which add some costs to the job..
Good luck/wwwthreads_images/icons/smile.gif

GeeAea

Figures don't lie ....... but liars sure do figure.

I don't know about the later model heads, but the 72 to 83 heads are a pain in the ass to do anything with.
The rockers set flat in the tops of the rocker towers, so the only way to adjust stock rocker arms is to shim them up off of the tower, and that creates a new set of problems.
(Comp Cams makes a 1.6:1 ratio roller tipped rocker arm with the correct spacing in the GM style that will work...BUT....)


1. The stock rocker towers are threaded 5/16" coarse for the stock rocker bolts.
Solution;
All aftermarket rocker arms I know of use 3/8" studs or bigger.
Most decent aftermarket studs have a 7/16" X 14 bottom, and 3/8" fine top end.
ALL good studs have a 'Nut' in the middle of the stud, between the 7/16" and 3/8" parts.
for a chevy style rocker arm to clear this 'Nut', and the radius just above it, you will need to have a machine shop cut the rocker arm tower down about 3/4".
Then the tower will have drilled out and threaded 7/16" X 14 to accept the stud.
(Chevys have pressed in rocker studs, so this machine work is a common practice in small block chevys)

2. The stock rockers were self aligning.
When you go to roller tip rockers, you are going to have to find a way to keep the rocker arms aligned with the push rod and valve stem
Solution;
Guide plates to hold the push rods in place. Isky makes a set of 2 piece adjustable guide plates that will work, but it takes MAJOR machine work on the heads to fit them.
BE EXTRA CAREFUL machining around the tow center exhaust towers, and removing meat from the area just above the exhaust crossover area. All of the EGR equipped heads we machined on were really thin around this area, and there is a water jacket you really don't expect there.
Once you get the spacing and alignment done, just weld the two halves of the guide plates together. Remember to number them for what cylinder they came off of...

3. Push rods.
Solution:
I found no push rod the correct length that was hardened for the guide plate in the correct position, so we once again had to custom make push rods.
We used one of the adjustable push rod kits, and welded them up when we were done.

Needless to say, it was a pain in the butt getting roller rockers on this engine. We have Comp Cams Magnums on it now, and they work fine, but after all of the machine work, I'm not sure I trust the heads...


--If someone knows of anyone that makes an easier set up, especially guide plates, let me know please.--

Thanks, Aaron.

So many cats.... So few recipes...