If the "461" is similar in design to the "462" camel hump heads, they are among the best-flowing stock SBC heads from the late '60s. They have relatively small chambers, and decent port volumes. Check the numbers at http://www.mortec.com
for details and specs.
If you don't already have 2.02/1.60 or larger valves, the heads will work really well with those changes. Pocket porting the valve bowls and reducing the short radius on both intake and exhaust runners will open port volumes a bit and increase higher RPM power.
For an early factory head, they are actually very well designed. There is usually plenty of material to perform the necessary port matching and radius blending, unless your individual castings had an unusually high degree of core-shift. Even at that, the older stable cast iron can be easily nickel welded and machined to create some really impressive port openings on both sides of the head. Don't forget to trim the extra casting around the valve stem bosses. If you can find a service that will induction harden the valve seats before final grinding, it may be worth the few bucks you'd spend. If you're still planning on using the ZZ3 cam and necesarily larger springs, don't forget to install screwed rocker studs.
Another little trick to increase intake flow with the larger valves is to roll the valve margin into the valve face a little bit on a polishing wheel. Just removing the sharp corner on face-to-margin break can help get air into the chamber around the tightly shrouded chamber walls (P.S. - don't tell the Ford guys about that one since it works well on 302s, too.) The exhaust valves don't really seem to benefit from this, probably since they are smaller and less crowded against the chamber walls. Some of the builders I talk with claim another 5-8 HP on this alone. Then again, talk doesn't win races.
At a minimum, check the castings for straightness and cracks. Perform all the machining you want, then clean them thoroughly. Old heads and cases can really get some scale buildup in the coolant passages, and the last thing you want on your fresh build is a hot spot or impeded coolant flow.
"Make Me Bad
" Adobe Acrobat Reader 4.0