Need Help Decoding some BBC Chevy Heads and Block - Chevelle Tech
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post #1 of 5 (permalink) Old Jun 20th, 10, 9:03 PM Thread Starter
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Steve
 
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Need Help Decoding some BBC Chevy Heads and Block

All,
I need some help in decoding some BBC Heads and Block I got for free.........

Here we go....................

The first set of heads (oval port)
-Pass 3931068 C18 9 GM3T
-Pass 2964290 D27 70 GM9T

What are they???

The next set of heads came with the block also (oval port)
-Pass 336781 J11 73 GM 11T
-Pass 336781 J10 73 GM 12T

The Block (454 2 bolt main)
casting # on rear of block - 3999289 GM T12 Pass HI PERF
number on deck T1012CWX 46448613

I think that the heads and block may be from a 1973 or 74 Chevelle / Monte Carlo 245 HP via the chevelle books I have. The HI PERF casting in the rear of the block is throwing me for a loop. The CWX code can also be for a 1972 454 270HP for a Corvette. I need some assistance in figuring out what I have here.
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post #2 of 5 (permalink) Old Jun 20th, 10, 10:48 PM
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Frank Riley
 
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Re: Need Help Decoding some BBC Chevy Heads and Block

HEADS:

I think your first head is actually 3931063:

3931063 68-69 oval CLOSED 396, 402, 427, 101cc chamber Cast 3/18/69

3964290 69-70 oval CLOSED 396, 402, 427, 454, 101cc chamber, Large or small hex spark plugs* Cast 4/27/70

336781 73-85 Oval OPEN 454, 118cc chamber, 256/114cc ports Cast 10/10 & 11/73


BLOCK: (Same block I have)

3999289 454 71-79 2 or 4-bolt mains (Some "CE" replacement blocks had four bolt main caps) Cast in Tonawanda 10/12 (of the casting date year, which you didn't include, its on the opposite side of the rear of the block as the casting number where the trans/bell housing bolts) Need to to know the casting date to translate the CWX make/model indcator.

All Big Block passenger (including lt Trucks thru 1 ton) blocks got the "Hi Perf PASS" designation to my knowledge.

Hope this helps....

70-454 LS5
Mid America Chevelle Club #293
Greater Kansas City
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post #3 of 5 (permalink) Old Jun 21st, 10, 5:17 AM
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Chris
 
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Re: Need Help Decoding some BBC Chevy Heads and Block

One of the Village People must have been working at the foundry when my block was cast because it reads "Hi Perf Ass".
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post #4 of 5 (permalink) Old Jun 21st, 10, 5:34 AM
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Jim
 
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Re: Need Help Decoding some BBC Chevy Heads and Block

Quote:
Originally Posted by chrisstandring View Post
One of the Village People must have been working at the foundry when my block was cast because it reads "Hi Perf Ass".
That's gold Jerry
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post #5 of 5 (permalink) Old Jun 21st, 10, 9:00 AM Thread Starter
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Steve
 
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Re: Need Help Decoding some BBC Chevy Heads and Block

Frank....thanks alot!!!

BTW, the casting date was pretty hard to read. I will need to look at it again tonight or tomorrow night to get it.
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