Rocker arm question.

I thought they also sold aluminum rollers for the SB Fords as well?

A quick look through their website...

SUM-G6940B Summit 1.6 aluminum full roller rocker arm for small block Ford.

3/8" stud, roller tips, set of 16, with lock nuts and allen wrench.

I think they were $195 (just closed the page)

JS

My mistake. I was searching with the online catalog. Summit has much more stuff that isn't in the cat. I still like the price of the chevy rockers better. 159.00 compared to the fords @ 195.00. I think there the exact same thing. Does anyone know if they're the same?

They are not the same, and won't interchange.

As I'm sure you know, Ford rockers can be had as either stud mount, or pedestal mount.

What's the difference, may I ask?

The stock design on many Ford engines is a pedestal. The raised flat top pedestal has a bolt hole in it, and the rocker arm fulcrum has a matching flat spot. To install, you simply tighten the bolt through the fulcrum into the pedestal. This makes the manufacturing process very simple. There's no adjusting, and any idiot with a wrench can install them. However, if anything has been modified, or changed, rebuilt, decked, etc, this no longer works. The distance from the tip of the valve stem to the centerline of the camshaft is now different. And if you're using performance parts (heads, cams, valves), the stock relationships no longer apply.

Way back in the 60's, converting to an adjustable valve train was an important upgrade. With more modern engines, you mill off the pedestal and drill and tap for a stud. Then you can use a quality roller rocker. If you go to this site, you can read a copy of the instructions for the FMS parts, which are essentially the same as all the others.

Also, the stock Ford design is a called a "rail" type. That means that the tip of the rocker is shaped in an inverted U, so that two side rails extend down below the valve tip. That keeps the center of the rocker arm located on the valve tip, and prevents the rocker arm from rotating on it's pivot. Interestingly enough, Coast High Performance makes an excellent alum full roller rocker with a rail tip; even in a 1.7 ratio (Crane used to, but I haven't seen them in a while). But you still have to get rid of the pedestal. If you don't use the rail type rocker, then you must use hardened push rods, and guide plates.

Let me append this a tad. According to Coast's web site, you can use their rail rockers on some unmodified heads. That's a big deal.

Bob, These rocker arms would be used on ford heads with 3/8 screw in studs and guide plates. Back in the day I've read about chevy people using ford

1:6 rocker arms to get more lift on their cams. Nowdays they offer increased ratio rockers. Again, what's the differenc between a ford 1:6 ratio roller rocker for 3/8 screw in studs vs. a chevy 1:6 ratio roller for 3/8 screw in studs?

It's a close fit, but not quite there. The critical measurement is from the valve stem to the rocker arm stud. If that's off by 1/16", you'll never get the correct geometry. If the parts were exactly the same, they would carry the same part numbers, and cost the same. 1-2 manufacturers would try and keep it a secret to hose you, but you can't keep a secret like for long. 1.6:1 is a ratio, not a measurement. To take this to the extreme, imagine a rocker arm that's 26 feet long. You can still have a ratio of 1.6:1, but it won't fit anything I've ever worked on.

I know it's a ratio. :)