455 Engine Build - New-Age Super Duty

Spiral locks are used to hold the wristpin into the piston-pin bore. If you've never done this before, prepare for some cut fingers and foul language. SRP pistons and locks are one of the nicest designs to work with but can sometimes be uncooperative. The piston-to-pin clearance is 0.0007 inch.

Since the factory crank was ruined when the engine failed on the dyno, an Eagle cast-steel crankshaft of stock 4.21-inch stroke and standard 3.25-inch main and 2.250-inch rod bearing journal sizes was chosen for this project. Here it's installed into the waiting cylinder block. Note the chamfered oil holes for better flow. The crankshaft thrust was set for 0.004 inch. Here you can see the thicker-than-stock 455 bulkheads of the SD block and that the block is not painted. Upon completion, Melvin will professionally paint it with a spray gun, not a can of spray paint. Melvin requested that RaceKrafters not even apply a light coat of primer before our photo shoot, so our engine is not as pretty as normal.

Craig employed a modern, rubber, rear main seal instead of the traditional, trouble-prone rope seal. It is nice that a company such as Fel-Pro, and a few others such as B.O.P. and Nunzi's Automotive, has made the investment to apply modern sealing science to a vintage Pontiac engine.

The main caps were torqued to 100 ft-lb (rear cap, 120 ft-lb) in two increments, and our SD started to look like an engine!

RaceKrafters prefers to use a very lightweight 5W-30 engine oil during assembly instead of an assembly lube, especially if the engine is going to be run shortly after it's completed. Craig also likes to apply the same oil to the piston skirt and sprays the installed rings with WD-40 before they enter the bore.

A tapered piston-ring compressor is a nicer and gentler way of installing a piston instead of a spring-style tool. The tapered compressor is bore-specific though, so one size does not fit all. Since RaceKrafters builds so many Pontiac engines, they have a ring compressor for all of the popular bore sizes. The piston-to-bore clearance was set at 0.004 inch.

The rod caps with bearings were installed and the ARP rod bolts were torqued to 63 ft-lb in two increments. Rod side clearance is 0.025 inch.

The Comp Cams roller hydraulic camshaft was lubricated with engine oil before installation. The cam (PN 51-423-9; grind number XR276HR-10) features a lift of 0.552/0.561 with 1.65:1 rockers. The duration at 0.050-inch lift is 224/230 degrees. Lobe separation angle is 110 degrees.

Since a Pontiac engine employs a thrust plate, there is no adjustment on the camshaft freeplay. The small hole in the plate needs to line up with the slot in the block. This passage is used to feed oil to the timing chain and gear set.

The Cloyes double-roller timing chain and gear set were installed on the engine in preparation to degree the camshaft.

Comp Cams recommended installing the cam at an intake centerline of between 105- and 106-degrees.

Craig was able to split the desired specification right in the middle, and the cam is at 105.5 degrees. He then used a paint pen to write the installed position on the timing gear for future reference.