The hydraulics used will work with both hydraulic and solid style camshafts. An excellent replacement hydraulic tappet for stock and high performance applications. Made to replace, and surpass 17920-53A (hydraulic unit) and 18522-53A (tappet). Note: Upgrading 66-84 Shovels to JIMS pushrods? Use the MCS 978053 JIMS Powerglide upgrade kit. JIMS Note: some 78-84 H-D® tappet blocks have oil drain hole location problems with some high lift cams.