rebuilding a rebuilt slant
Will the hydro. valve train work on a 75 head? I know that the rocker shaft and one bolt in particular I specific to the hydro setup. What provisions would I have to make to the mechanical head to use the hydro valve train?
There is a great discussion on slantsix.org if you search (ca 2003). I read it just a few weeks ago. Charrlie_S who responded already was one of the posters (he is a slant racing guru). As a quick summary:
The different bolt is unrelated to the hydraulic cam and actually pre-dates it. It was so people install the rocker shaft correctly. However, it seems you may need it for the hydraulic rocker shaft, or maybe drill the rear bolt hole bigger in the shaft.
I recall discussion of drilling an oil passage in the block larger to allow more oil flow to the top. At least hydraulic heads had the larger hole. Nobody ascertained it is required, and seems unlikely to me it would be since rocker arm clearances are probably the main determiner of flow rate needed. Run a wire thru each rocker arm to insure the oil hole is clear.
Much discussion has long been made about the rear cam bearing being different in hydraulic engines, i.e. with a center groove, and that being necessary. A study of PN's suggested there was no changed PN for that bearing, but other ones unrelated to a hydraulic cam did change PN (narrower), probably because their webs in the block got thinner. There never was a grooved cam bearing, it was the rear journal that has a groove in a hydraulic camshaft.
In sum, you probably don't need to touch the block or heads, just install all the hydraulic stuff (camshaft, rockers, pushrods, & lifters).
Let us know what worked.