Buick, Olds, and Pontiac 455ci Engines - Cylinder Heads

Buick Olds Pontiac 455Ci Enginez Hydraulic Flat Tappet

A modern, aggressive profile, Comp's XE274H Xtreme Energy hydraulic flat-tappet grind runs strong on the street yet still delivers enough vacuum in a big-block to run power accessories.

A modern, aggressive profile, Comp's XE274H Xtreme Energy hydraulic flat-tappet grind runs

Cylinder Heads
Engine technology has come a long way since the '60s. The biggest advances have been in cylinder-head and camshaft design. That's where the power is, and if you're on a budget, that's where you should spend your hard-earned bucks. We went with Edelbrock's Performer RPM Olds heads, which come complete and ready to run with stainless steel 2.072-inch intake/1.680-inch exhaust valves, hardened ductile-iron valve seats, phosphor-bronze guides, valvesprings, guideplates, and rocker-arm studs. Out of the box, they flow about as well as today's modern aluminum 23-degree small-block Chevy heads-which is quite an improvement over production Olds castings.

Buick Olds Pontiac 455Ci Enginez Edelbrock Cylinder Head Flow

Induction, Ignition, Exhaust
The Olds was equipped with an Edelbrock Performer dual-plane intake fed by a Speed Demon 750-cfm carb, ignited by an MSD billet Olds distributor, and exhausted by Hooker Super Comp headers. Note that the port openings on most street-header flanges are actually smaller than the port exit dimensions of many big-block Olds heads. Hooker 171/48- and 2-inch primary-tube header sets are exceptions.

Test Results
Based on prior experience with big-block Olds engines, we expected a torque monster, and we weren't disappointed. With 38 degrees of total lead and No. 80/86 jetting in the Demon carb, the engine put out so much torque at so low an rpm it exceeded the capabilities of Westech's SuperFlow dyno. Westech recorded a peak of 565.3 lb-ft at 3,500 rpm, but that was already on the downside of the slope. We may, in fact, be looking at a 600-lb-ft engine! The engine made more than 500 lb-ft from 3,500 through 4,800 rpm and more than 400 hp from 3,800 through 5,500 rpm, the highest rpm point obtained in the test. A peak 469.6 hp was recorded at 5,200 and 5,300 rpm. While these numbers make for a tire-melting street engine, Westech feels an intake optimized for higher-rpm performance-such as a Performer RPM or even a Victor Jr.-is needed to fully unleash the potential of Edelbrock's Olds heads. An Olds 455 makes so much low-end torque it's almost impossible to hurt the bottom end. Edelbrock, are you listening?

Fel-Pro recently introduced a premium heavy-duty Olds head gasket with preflattened steel wire and a steel-core laminate. Except for the intake gaskets, Fel-Pro also handled the rest of our engine's sealing needs. Premium Edelbrock head bolts ensure positive retention of the aluminum heads.
Fel-Pro recently introduced a premium heavy-duty Olds head gasket with preflattened steel

Edelbrock's heads use the same 1.6:1 rocker arm as a Ford Windsor small-block converted to adjustable stud-mounted rockers and 71/416-inch rocker studs. We chose Comp aluminum roller rockers for durability. Edelbrock supplied the springs and retainers with the assembled heads.
Edelbrock's heads use the same 1.6:1 rocker arm as a Ford Windsor small-block converted to
Edelbrock's aluminum Olds heads feature an improved 77cc chamber that increases the quench area for a more efficient burn. The high-velocity, factory-location ports feature 188cc intake runners and 106cc raised-floor exhaust runners for substantially increased flow and power.
Edelbrock's aluminum Olds heads feature an improved 77cc chamber that increases the quench
Olds engines use a one-piece metal valley pan to seal the intake manifold to the heads; it doesn't work well with aluminum heads and intakes, so Westech used conventional Mr. Gasket side gaskets (PN 404) plus silicone beads in lieu of end seals. Don't forget the stock valley oil baffle (arrow).
Olds engines use a one-piece metal valley pan to seal the intake manifold to the heads; it