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post #1 of (permalink) Old 07-24-2000, 05:36 PM Thread Starter
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Casting numbers...???

I have a 454 and the casting number on the heads is: 336781 , I'd like to hear every last little bit of info about them you guys have... [img]/wwwthreads_images/icons/cool.gif[/img] Thanks

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post #2 of (permalink) Old 07-24-2000, 06:18 PM
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Re: Casting numbers...???

Mortec has info on BB heads too, unfortunatley they carry even less info on BBīs than on SBīs. Other than oval port, made from 73 to 85 and sitting on 454īs exclusively, I have no "real" info for you. Whereīs Dave when you need him[img]/wwwthreads_images/icons/wink.gif[/img]


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post #3 of (permalink) Old 07-24-2000, 08:49 PM
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Re: Casting numbers...???

Check with for some information. I've not built enough big blocks to be very helpful. The oval port heads do work well for a mild performance (about 1 horse power per cubic inch). Just be careful with the springs in the heads of a big block. The stock springs are only able to handle about .487" of lift! I've seen several cam lobes worn down just after a performance camshaft was installed because the valve springs would bind. I would guess that the heads you have are 119cc. Watch the compression ratio on a big block, seems there very sensitive to compression ratios above 9:1.

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post #4 of (permalink) Old 07-25-2000, 12:41 AM
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Re: Casting numbers...???

Thats a good set of heads you got. My Chevy Big Block Performance book reccomends them. They currenly have 2.06 intake, 1.72 exhaust valves. You could easlily fit 2.19 and 1.88 valves and get some great performance. It goes on to say that they can make power up to 6500rpm's and still make great low end torque. They dyno tested a oval port 468ci with 10:1 and cam duration of 255 which resulted in 575hp and 520lbs of torque. I know that compression is a little high for a truck but not bad for a streetable 454. When they bumped up the compression to 12:1 with a larger cam, they got 615hp and 540lbs! I just had my 049 heads fitted with the 2.19 valves and will soon be installing Holley MPFI. Can't wait.

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