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- Butler/Edelbrock Ported Top End Power Packages 575-700+ HP Pump Gas
Butler/Edelbrock Ported Top End Power Packages 575-700+ HP Pump Gas
Pontiac V8 Butler/Edelbrock Ported Top End Power Packages 575-700+ HP Pump Gas
Ported Heads, Pump Gas — Butler/Edelbrock Ported Top End Power Packages 575-700+ HP Pump Gas for Pontiac V8s
The 575-700+ HP pump gas packages are built on Butler CNC ported round port heads instead of out-of-the-box castings. Every kit here uses 2.19"/1.77" valves, a hydraulic or solid roller cam, and an intake port matched to the specific flow level of the heads — which is why the flow number is in the product name.
Three levels: round port ported to 325 CFM, round port ported to 340 CFM, and the CNC wide port head at 370+ CFM in hydraulic and solid roller versions. Chamber choice is 72cc or 87cc across all of them.
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1. The Three Flow Levels and What They Make
Output here is tied to cubic inches as much as to the head, and Butler publishes the pairings.
| 325 CFM round port | 550-600 HP on pump gas. Pump gas on a 400 or 428; a 455 and up will want high octane. |
| 340 CFM round port | 590-700 HP on pump gas, broken down by displacement — 580-620 HP on a 461-474, 625-650+ on a 505, and 675-700 on a 535. |
| 370+ CFM wide port | The top of the program, offered in hydraulic roller and solid roller versions in 72cc and 87cc. |
| Cams to match | Butler/Comp street performance billet roller grinds at 110 and 112 lobe separation, with lift figures listed both at 1.5 and at 1.65 rocker ratio. |
2. The Intake Is Matched to the Flow Number
You cannot move an intake between these tiers and expect the port match to survive.
| 325 CFM kits | Edelbrock 7156-325 Performer RPM, 5056-325 Torker II, or the Butler Northwind 4150-325, each port matched to the 325 cfm heads. |
| 340 CFM kits | The Butler Northwind 4150-340, a low-rise 356-T6 aircraft aluminum 5-axis CNC machined manifold with a 4150 flange, port matched to the 340 cfm heads. |
| Wide port kits | Require an intake with enough port height to be port matched — Edelbrock 2957 or 29575, NW4150, NW4500 or sheet metal. |
| Hood clearance | The Performer RPM is 7/8" taller than stock and will not fit under a Trans Am Shaker hood without modification. Sort that out before ordering. |
3. What Comes With the Wide Port Package
The wide port kits carry more hardware than the round port ones, because the head demands it.
| Valvetrain | T&D shaft mount rockers at 1.65 ratio, plus Comp Evolution hydraulic roller lifters on the hydraulic version or Crower offset solid roller lifters on the solid roller version. |
| Sealing | Cometic .040" head gaskets, matched intake gaskets, ARP head studs and stainless intake fasteners. |
| Also in the box | A port matched intake and a pushrod length checking tool. |
| One caution | These heads can be used with hydraulic roller cams, but doing so requires solid roller lifters. |
This tier assumes a short block that can take it and a fuel system and converter to match. If any of the octane notes above are a problem for the engine you have, the 450-550 HP packages on unported heads are the sensible stop instead.
Not sure what your Pontiac needs?
Call our tech team at 866-762-7527. Tell us your engine, heads, car, and power goal, and we will put the parts together as one combination that works.