I would also install forged rods, dished KB pistons, and the stock top end (#64 heads, '70 intake, Q-jet, and so on). The dished KB pistons (now Icon pistons) will allow pump gas with the high-compression heads. For this combination, I usually recommend a Comp Cam XE hydraulic-roller 236/242 cam, but the Q-jet needs to be modified for the duration used. Keep in mind this is for the dished pistons and lower compression, and is borderline pump gas for certain areas (quality and octane of pump gas).
For the budget-minded and definitely pump gas, the typical RA IV type cam would work well. That also needs the Q-jet modified for the larger duration. I've also used both the 4.250 and 4.500 stroke (both cast and forged for the 4.250-4.500 is forged) with dished pistons (if you use the 64 heads) to make your 455 a 461 to a 495-CID engine, depending on final bore and stroke. More stroke is more torque for your heavy (over 4,000 pounds) GTO. So as you see, you have many, many choices.
Shaker For A 403 Olds
My '79 runs a 403 Olds, and I have some shaker ideas for this Olds motor. I prefer an Edelbrock 7111 over a 3711, and I have an earlier shaker scoop, a Barnum 491982 that lines up on the stock 403 air cleaner. I may need a shorter filter element, however. Has anyone used a similar setup with a shaker before?
Chris Hohenfels
Poughkeepsie, NY
Rocky Rotella responds:
Welcome to the wonderful world of Pontiacs! The Edlebrock Performer intake manifold for small-block Olds (PN 3711) is generally considered a stock replacement unit, allowing the use of the factory Shaker assembly and positioning it in the correct location. According to Edelbrock's website (www.edelbrock.com), it's most effective when used up to 5,500 rpm. The Performer RPM for small-block Olds (PN 7111) is roughly 2-inches taller than either the stock unit or the Performer, and it's designed for operation as high as 6,500 rpm. As you've found, it does not allow the use of the stock Shaker assembly without modification.
There are a few drop-base kits on the market specifically designed to retain the Second-Gen Trans Am's Shaker in the stock location. To the best of my knowledge, however, both are designed for use with the Pontiac V-8 but can be altered to fit the Olds V-8. You can learn more about them by contacting Blocker's Performance at www.blockersperformance.com or WFO Performance Works at WFOTECH@comcast.net. If you believe you've already purchased everything you need to replicate such a kit, then you might use either as an example to gather ideas on how to fashion yours.
In stock form, the 403 Olds isn't generally thought of as a high-winder. I don't know what modifications you've made to the engine, but if it's close to stock, there might not be much gained when using the Performer RPM over the basic Performer. If your combination is such that the engine will continue making power above about 6,000 rpm, then a Performer RPM might be for you. If your engine will be run at a maximum of 5,500 or less, then the effort installing a Performer RPM and modifying an air cleaner to fit may not be worthwhile.