Big block camshaft question

devo said
Oh yeah, I cant seem to find anything about what the difference is in the solid roller and hydraulic cam shaft themselves..are the lobes ground on different profile on the solid for the solid lifters?is the core material different?All I can find is the solid uses solid lifters and the hydraulic uses hydraulic lifters and is it bad practice to mismatch the two?ie solid roller with hydraulic lifters and vice versa apologise for all the questions but you guys did say fire away lol

The basics:
Hydraulic flat tappet - cast cam core (the blank the cam is ground on), lobes have taper ground in to spin the lifters during the opening and closing ramps. Uses any oil pump drive. Rate of lift (and thereby duration) are limited due to lifter diameter and the hydraulic system within the lifter that dampens the initial lift and takes up any freeplay (or "lash) within the valvetrain. Depending on pushrod you can use non-adjustable or adjustable rockers.

Solid flat tappet - same cast cam core as hydraulic. Same oil pump drive. Same taper on lobe to spin lifter. Rate of lift can be faster - sometimes much faster - depending on lifter diameter. Rate of lift is not dampened as there is no hydraulic function within the lifter. Must run adjustable rockers of some type because the freeplay in the valvetrain is sset by the rocker adjustment.

Hydraulic roller - Billet steel cam core. Needs bronze oil pump drive. Some small block cams can be ordered with cast gear to use any oil pump drive, I do not believe any big blocks cam be ordered that way but not positive. No taper on lobe because roller needs a flat surface to ride on. Rate of lift is milder than solid flat tappet, similar to hydraulic flat tappet due to the hydraulic system within the lifter that dampens the initial lift and takes up any freeplay (or "lash) within the valvetrain. Solid rollers can be used on lobes designed for hydraulics. End play setting of camshaft is necessary. Requires comparatively heavier valve spring pressure to maintain stability with much heavier lifter. Depending on pushrod you can use non-adjustable or adjustable rockers but adjustables and custom pushrods are recommended. In my opinion - block needs to have lifter bores bushed to run soller lifters. Some debate that but it's important enough for me to mention.

Solid roller - Same billet core. Same oil pump drive requirements. Same lack of taper. Fastest rate of lift possible depending on roller diameter and spring pressures. Lifters can be heavy or much lighter depending on design and block prep. Hydraulic roller lifters should not be used on solid flat tappet lobe designs. Same setting of endplay. Needs adjustable rockers. Same opinion on bushing the block.