haven't messed with smallblock stuff for a long time. what's the stock rocker ratio of the magnum that uses stud mount rockers. also for the factory roller which i "assume" is a steel core? what do they do about the distributor drive? tnx

rocker ratio is 1.6, and I belive it uses a standard dist drive gear

Yup, 1.6 ratio, and stock distributor drive. The biggest difference in the cam is that it has no real provisions on the front for Fuel Pump eccentric. As long as you run an electric pump you'll be fine.

There are some hoaky eccentric conversions for those cams, but I'm not all that fond of them...

sp what's the deal with the cam to drive relationship? afaik you can't run a steel cam core against a cast distributor gear. iirc some manufactures actually put a cast gear on the steel cam core.

The factory cam as well as MOST aftermarket cams are cast cores,work fine with the factory oil pump drive gear. Billet cores will need a bronze drive gear. The 2pc cores that Crane made are hard to find. Last time I had Comp do me a custom they had a few left,I don't know if they still are.

What's your concern? It's not like Magnums don't have a distributor. They use a cast gear just like anyother small block factory cam. Unless it's a billet roller cam, it's no big deal.

The distributor gear was a big problem on those motors originally then the gear material was changed and that seemed to solve the problem. From what I was told, the Mopar Peformance gear that you can buy for the SB uses the updated material and there doesn't seem to be an issue anymore.

Yeah, I know it can be done, but I just don't like the fact that it's only got what... .200" of keyway engagement into the timing gear?

The depth of engagement doesn't matter in this case because the key is in shear across its face (.25" x .25", for example), between 2 components mounted side-by-side.

For 2 items fixed to each other by ID/OD, then the length of the key matters as it is in shear across the whole length (.25" x 1" long, for example).

Might not have used 100% accurate description, but the theory stands.

Consider that the camshaft gear uses only a small rollpin to locate it; the clamp force between bolt/washer/camsnout carries the load there. This fuelpump extender is a similar situation.