Chevrolet small block V8 cylinder heads guideplates
Chevrolet small block V8 cylinder heads were not always equipped with pushrod guideplates and screw-in rocker arm studs. This can be a bit of a surprise to some of the younger performance enthusiasts out there. For about the first 15 years, the rocker studs were press-fit into the stud bosses, and oval-shaped holes in the head casting itself guided the standard diameter 5/16″ pushrods. Yes, the studs would pull out when high valve spring pressures and high RPMs were used, so a more reliable method was needed. Staking the studs with either tapered or straight pins was tried, but screw-in studs provided the best answer, and there was a mass conversion of the older heads in the late 60’s.
To properly perform this update, the press-in studs are removed from the cylinder heads, and the top of the stud bosses must be machined down .380″ to accommodate the hex portion of the screw-in stud. The 3/8″ stud hole in the casting must now be drilled and tapped to a 7/16″x14 thread. (The 3/8″ studs and the 7/16″ studs both have a 7/16-14 bottom thread.) The studs can now be properly torqued into place. If you also want to incorporate pushrod guideplates at this time (particularly if you want to use 3/8″ diameter pushrods), the holes in the head that previously guided the pushrods must be drilled out for clearance. If you don’t do this, the pushrod guideplate slots and the holes in the head castings will have a conflict, putting the pushrods in a bind. This will cause premature pushrod wear and possible failure. The pushrods will now have to be heat treated for use with guideplates, since the original pushrods did not require additional hardness when being guided by the cast iron head.
Since there are restorations that require the earlier heads, and some sanctioning bodies and classes that mandate these, there is still the need to update them to a modern, reliable valve train configuration.
Source- Crane Cams E-News Issue 216
The Hays Clutch Cable Kit is a must when installing a high-performance clutch in 1981-2004 Ford 5.0L Mustangs. This kit features a billet aluminum quadrant for strength that replaces the weak factory O.E. plastic unit which is fast-wearing and prone to failure. The quadrant is designed to increase leverage, therefore decreasing required pedal effort. The heavy-duty low friction cable is made of stranded steel and has durable metal fittings with the added feature of an adjustable fork end for exact adjustment of clutch release and pedal freeplay. Comes complete with all hardware and detailed instructions for ease of installation.
You don’t always need big cfms to get great performance. Holley’s 470 Off-Road Truck Avenger is the first carburetor designed from the “flange-up” as a hard core off-road carburetor specially designed to work on small cubic inch motors such as V-6’s, Inline 6 cylinders and small V-8’s. No other carburetor comes close to the Truck Avenger’s ability to offer peak performance at extreme vehicle attitudes over rough terrain. Holley begins construction of this carburetor with the exclusive “No Trouble” metering block eliminates fuel spillover through the boosters at extreme angles. Flood-free operation up to 40 degrees while climbing and 30 degrees during side hill maneuvers and “nose down” descents. This allows you to off-road with confidence without the annoying hesitations, stalling and flooding typically associated with carbs in an off-road environment.Other features include;New Annular Boosters provide incredible low and mid-range throttle response and torque.
The Vortec L31 version of are available now.These kits provide everything needed to convert from a single carburetor intake to a dual-quad intake for small-block Chevys. Kits include the new RPM Air-Gap Dual-Quad intake, two 500 cfm carburetors that are not your typical out-of-the-box carbs but Thunder Series AVS carburetors calibrated specifically for dual-quad applications (one manual choke, one electric), our high-tech progressive throttle linkage, fuel line and intake gaskets.The manifold and carbs are available with a standard finish or with the new EnduraShine™ chrome-like finish for show quality looks that last.