View Full Version : 396 heads (closed chamber, oval port)


kz1000ltd
Feb 17th, 00, 05:17 PM
Somebody tell me about these heads, cast#
3964290......All I know is that they are closed chamber, oval port......What would be a good intake,cam,carb combination for these heads? I don't know anything about the internals of the motor, although the owner
said it had flat tops? The motor is a 396, block #3916323.....Currently has an Edelbrock Performer 2.0 and a Holley 600, it runs fine, but seems to me I can get alot more out of it. I know I need a bigger carb, it's the combination I'm interested in.
What would be good? I'm hoping for around 400 horse.......Thanks.....KZ

[This message has been edited by kz1000ltd (edited 02-17-2000).]

[This message has been edited by kz1000ltd (edited 02-18-2000).]

mike brown
Feb 17th, 00, 06:08 PM
3916323....396.......'68
3964280 ? couldn't find it, how about 3964290....'69-70...oval port...CLOSED CHAMBER...396, 402, 427, 454 Large or small hex spark plugs used.
would guess you need about a 750 cfm carb (probably came stock with a 750 quadrajet)
the performer is pretty much a stock replacement which should be fine if no mods to the motor. might look at the performer rpm if you have a hotter cam, etc. sorry i'm not much help, but maybe someone will be able to tell you more.

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To see a pic of my car, click here... pages.prodigy.net/mtbmtb/rf396ss.jpg (http://pages.prodigy.net/mtbmtb/rf396ss.jpg)

big gear head
Feb 18th, 00, 01:09 PM
The 290 head is popular with stock eliminator racers. It's a very good head, especialy when ported by someone who realy knows what they're doing. Call your fevorite cam maker for a good cam choice. 750 holley and performer rpm sound good to me. The pistons should have about a .100" dome for a good street engine.

69Man
Mar 19th, 00, 05:14 PM
My Big Block Chevy book says these are 65-76 345,360,390 HP 396,454. As far as I'm aware, the 396 never had flat tops. My 396 has .182"domes and they are 10.25 to 1 comp. They actually say that open chamber heads increase your horsepower. The pistons do not shroud the valves like closed chamber. Allowing more air intake increases hp. I would suggest a Comp hydraulic cam such as the 268 to 274 Extreme Energy, depending on what gear ratio you have, and trans, stall converter, comp., etc... These cams give you more vacuum than others on the market, and they will give you a rumbly idle, but can still use your stock torque converter. Use a good dual plane intake manifold, aluminum preferably. I would recommend a 750 cfm carb. I would stay vacuum secondary though, more streetable/ecomical. These engines like their fuel!

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Jeremy Mc.