Roller Rocker ?'s

[bushwackertn]

My son and I have a 360, we are getting ready to install a set of 291 heads on it as soon as we get them worked. These heads have already got 3/8 screw in studs in them. We are going to buy a new set of roller rockers for them, but don't really know what to buy? Should we go ahead and buy 7/16 studs, or are the 3/8 good enough, we will only be turning around 5,500-6,000 rpm's. I have heard that ford small block rockers will work, is this true? I was also wondering about clearing valve covers, I really don't want to change valve covers. We gave allot for the one's we have, but they are factory height.
Also do we need the guide plates with the 291 heads? The push rod holes are pretty small in the heads.

[tufcj]

I have 291C heads on my 69 AMX w/rollers. If you haven't bought the rockers yet, buy ones built specifically for AMC, most manufacturers make them. Mine are Crane gold. Ford will work, but you may have to play with pushrod length to center the roller on the valve. The neck on the factory stud is too tall to allow them to adjust, so you need to swap out the factory valve studs for aftermarket. I used SBC studs from ARP, and left them at 3/8". As long as you aren't going with lifts much over .500", or crazy spring pressures or RPMs, 3/8" wll be fine. You don't need guide plates with the 291 heads (that's why the pushrod holes are oval), but you will need hardened pushrods. Replace them with new, it's cheap insurance. Since I put Gen3 heads (70-up) on a gen2 block (67-69), I had to run +.100" pushrods to get the rocker geometry right. You probably won't have to do that. They do fit under the stock valve covers. Mine are actually under a set of vintage Edelbrock aluminum covers.

Bob
tufcj

[bushwackertn]

If I'm going to have to buy the studs anyway, why not just go ahead and get the 7/16 studs to start with? Or do you have to drill and tap the head for the 7/16 studs? From what I have seen the rockers are the same price for 3/8 or 7/16, I think that I would rather go ahead and get the 7/16, if I don't have to do to much to change them over, we are going to have to take the heads to a machine shop to get them worked anyway. If I do go with the 7/16 studs, will the small block chevy work as well?

What about the COMP CAMS, roller tip rockers that look like a factory rocker arm? Do you still have to change the studs for those as well? Or will these rockers not do as much for more power as the Crane Golds will? Comp Cams advertise a 15-30 hp gain with those rockers. I have also looked at the Scorpians, although they are a little on the pricey side.

I have also found some C.A.T. factory style roller tip rockers for $69.99 for a AMC 360. But I have not heard much about them, said that they are rated for 350 psi springs, and a 15-30 hp gain. We are running a .488 lift cam with 284 dur. we got the springs with the cam, and I'm not for sure about the spring pressure. I don't think that it would be anywhere near 350 psi though. We also installed hardened push rods when we put the cam in about a month ago.

[tufcj]

The heads are already 7/16", so SBC studs will thread right in. The factory studs are non-adjustable, that's why they have the shoulder. The spec is to just torque the nut to 30 or 40 ft/lbs. If you want the adjustability, you need to go with new studs and locking nuts. I've never dealt with just roller tip rockers. In spending the money, I go with the full roller rockers. Just watch the cheapies, and some use a smaller diameter pivot, and that means less roller bearings, and more pressure per roller. Valve train is not a place to scrimp to save a few bucks, it's one of the most abused parts of the motor. Just my thoughts.

Bob
tufcj

[Rogue Racer]

The bulk of the friction in the stock rocker arm is in the ball, not the tip. Comp Cams roller tip, ball-mounted rocker arms do little to improve the stability or strength of the valve train. Go with the 7/16" studs, good quality full roller rocker arms like tufcj says. The money will be well spent.