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Old 10-23-2000, 10:24 PM   #1
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flow numbers for heads

I have been searching the net and have come up short.

I need some flow numbers for my heads

casting number
3782461

Vader if you are listerning how about a little more help here!

I like to know all I can about what I got

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Old 10-23-2000, 11:12 PM   #2
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85,

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.

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Old 10-23-2000, 11:21 PM   #3
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You've got a pair of the original camel hump heads found on 1961 -1966 iron (most noted for being on the 1962 "Fuelie" Vette). They were produced in both the small and large valve versions. The intake runner is 155 - 158cc and if stock does not move a lot of air. The old 461 heads have the "low" spark plug location and therefor do not make them a good candidate for "pop up" or domed pistons,,, especially if the heads have been milled.

The following link gives some flow data for a set of "462" heads,,, which were patterned after the 461 heads,, except GM raised the spark plug location slightly and relieved the quench area behind the plug a little. I would expect the 461s to have similar flow numbers though.
http://everythingnova.homestead.com/headflow1.html

Good luck!!!!!

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Old 10-23-2000, 11:45 PM   #4
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461 castings typically have 165cc intake ports. These were used mostly by SuperStock class because of the small compustion chamber and the large ports and a unported head rule.

Even open chamber heavy casting smog heads such as 997's flow through 160cc ports.

Dart heads are better right out of the box. S/R Torquers are 171 and Sportsman's are 200cc

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Old 10-25-2000, 01:21 AM   #5
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Well the link I posted above got 156cc out of the 462's they tested and I've only seen one totally stock set of 461s and we got 155 cc for them,, so I sure can not agrue the point on one or two sets of heads. However, I did check and see that David Vizard qoutes 158 - 160 cc for the standard 461 runner size and mentions the 461-X,, that I had forgot about - They have 175cc runners - nice!!

For sure the SR will flow better than the 461s and so will a set of Vortecs. Both of which could cost less than refurbishing the old 461s - In an apples to apples comparison.
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Old 10-25-2000, 01:21 AM
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