Magnum Headaches with Prototype Stuff

[340king]

Hi Y'all,

I just wanted to let you know what I've been up to for the past month or so. First, I went to Guard Camp and lost two weeks of connectivity. Then upon returning, some new software was installed in my computer causing a conflict with my browser for another week. Then there is this thing called work.

The reason for the post is to let everyone that wants to follow in my footsteps with Magnum heads on an LA block know what I have found.

The first question in this buildup was what head to run. The rules call for flat top pistons that cannot come out of the deck. We decided to try the magnum heads for the closed chamber and the nearly identical flow to the 360 high-swirl heads. Then the decision on what valve train to run. The class calls for any flat tappet cam and stock valve gear. That left us with the choice of using Chevy or Ford parts for valvetrain and the associated problems with pushing push rods through the rockers and stud flex. The stud bosses on the magnum heads would have been real thin after drilling them out for 7/16" studs.

We decided to adapt shaft rockers to the thing. This seems like an easy engineering exercise. Just make a shaft adaptor and bolt them on. As it turns out it is quite a bit more complicated than that. The length or height of the roller lifters allowed Mopar to cast the intake rails of the heads thicker. Fine if you are using a roller cam, but the rules dont allow this. The pushrods had a nasty interference. I think we have sorted out this and a few other things. The hope is to have a kit available to swap shaft rockers onto the Magnum heads for better valvetrain reliability.

Sorry for my absence, I will post when we get things worked out.

[LA360Dart]

Hi 340king;

I'm in the process of putting Magnum heads on a LA short block. The block is together and I'm looking at Oldsmobile and Chebie stuff to make it work. Studs, guide plates from CompCams(Olds). Rockers 1.6 with rollers(Shivy). Then make a stud girdle to tie it all together. Will let you know how it all works. Hopefull will be stable using a small cam at first to get it set up.

Denny

[340king]

You probably shouldn't have a problem, unless you are going to run a flat tappet cam shaft. Then the problem with the pushrod interference will/should occur. We are restricted like I said to stock type stuff. I would have liked to have tried the MP roller stuff.

If you are going to run the Chevy studs, then the heads will have to be drilled out to 7/16". I was a little leary about the stud bosses cast into the heads. They appear to be a little on the wimpy side for a 7/16" thread bore.