I am having new 600 CI motors built. They are all Aluminum Merlin blocks and Brodix Alum heads. My question is about stud girdles. My builder has them on the quote and I'm wondering if they will help anything or are they not needed? I have never seen them on marine Engines before. They will cause me to use tall valve covers and I may need to use spacers on my exhaust. This is not a big deal if there is some benefit. Thanks

I am not the expert, but if you are going to that expence why would you not use shaft mounts?

IMO, it's either stud girdles or shaft mount, going without is not an option.

If you are buying everthing new go with the shaft mount rockers in stead of the girdle's. The price of stud's , rocker's and the girdle's add's up to just short of what shaft mounts will cost you . just my .02

Jesel or T&D shaft the only way to go
Yes the lift and spring pressure might not be there but the constant rpm load is.
Jim

Has anyone tried the Crower stainless shaft rockers, they're cheaper and stronger than aluminum.

What type of cam? If your going to run a hydraulic roller they are not needed. Solid roller use shaft mount rockers. They will fit under the KE low profile two piece valve cover. I would not use a stud girdle on any engine they make it impossible get valve lash set and stabilized on mechanical cam and little or no benefit with hydraulic cam. The pedestal Jesel rockers would be a good second choice for either and will also fit under the low profile valve cover.

If you are not planning on spinning the motor real fast, you prob dont need either girdles or shaft mount. I do agree, if starting from scratch, might as well go with the shaft mount setup. The cost as stated wont be that much difference once you figure in the cost of new roller rockers, studs, girdles, and poly locks. Probably a difference of about 400 bucks a motor. But you will have a sweet valvetrain setup. jesel shaft system, and jesel belt drive for the cam=nice

what would be the advantage of a belt drive?

Belt will not stretch as bad as a chain keeping the cam in time better and no harmonics transferred from the crank to the cam.