GW, the roof is "done" with the Ram Air IV opening. No place to go "up". For a milder build, I guess they'll do the job. If you want 'more', though, it will call for new heads. Most of our customers want at least 325 from their E-heads for the 461s. We have a solid roller grind that works really well with them. And if one "catches the fever", there's room for a LOT more in the round port OR the KRE D-port.
KRE D-ports, as said earlier, have more potential than the Edelbrock D-port. The KRE Highport, on the other hand, isn't really in the same "class" as the Edelbrock round port. The HP falls in between the E-head and Tiger. An excellent mid-level race head, on a BIG motor, could be good street heads, too. Valve lengths make it a little tough to work with, as only 1 source for "drop-in". We're currently working on a 505 project using them. Wait 'til you see the intake Dave created for it...
Jim
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