Block Casting Numbers
 

I am looking for info on a block i have had under my work bench for 25 yrs. It is a 427 4 bolt main with the tall distributor boss. The casting as i can make it out is 3903854. The 3 may be a 5? No pad cods now as it was a race block. Has a K14 cast below # 7 cyl. HP cast every where. Thanks.

Re: Block Casting Numbers
 

Sherm,

I can't find this block number anywhere. Can you tell me a
little more about it?

Does it have the two dowel pins on the timing cover?
Does it have provisions for the screw on type oil filter,
or the older cannister type?
Where is the casting date located? Is it on the right side
of the block just above the center freeze plug? Or, is it
on the upper rear flange behind the right cylinder head?

In most cases, a tall distributor tower indicates an early
style casting. Late in the 69 model year, the short tower
was phased into production. Although, I have heard that the
'512 block used the tall tower design through the end of
1969 production. Possibly others here can verify that.

Steve

Re: Block Casting Numbers
 

BTW, the only '854 block I can find is the 3969854, which was
the first 402 block used in late '69 production. However,
that block was reported to incorporate the "new" short
distributor tower design. https://www.yenko.net/ubbthreads/imag...mlins/hmmm.gif

For reference, the '854 block I have here uses the short tower design.

Steve

Re: Block Casting Numbers
 

New info on block! Talked to someone who refreshed my memory on this block.
In the late 60s and early 70s the NHRA required you to run the same year block as the car in SS and stock. When these camaros were new the blocks were not that easy to find. This blocks numbers were changed to fit the class they were running at the time. The numbers on the block now are 3969854. I know the 9 and the 6 has been changed. The three i an not sure about. The casting num on the side of the block below the freeze plug is J 10 8 It has a screw on oil filter. Also has the extra plug at the oil filter for external oiling. I still would like to know what this block was born in. Thanks for your input.

Re: Block Casting Numbers
 

There was a 454 block 3969854 2 or 4 bolt in addition to the 3969854 402. I may be off on the years but I think 70-91. https://www.yenko.net/ubbthreads/imag...lins/dunno.gif

Re: Block Casting Numbers
 

Tall Distributor boss, 396?85? 4 bolt main, casting # J 10 8

Re: Block Casting Numbers
 

No I don't think that 454 would have a tall boss. It is not a tall truck block by any chance. Not all of them had truck stamped. They were 3969852 for the 366 and 3969858 for the 427 from 68-85. cannot see it if you raced it but just to eliminate another possibility. Easiest way to tell is how much material is there between the top of the water pump bolt hole and the top of the deck. Truck block cannot be missed when you look there.

Re: Block Casting Numbers
 

The 3969854 block was a 402. GM would not use the same
casting number on different c.i. displacements.

The J-10-8 however is way too early for an '854 block
as they came into production late in summer of 1969.

Check that casting date again.

Steve

Re: Block Casting Numbers
 

Chevelle boys and other lists state differently Steve. 854 was also a 454.
https://www.yenko.net/ubbthreads/imag...mlins/hmmm.gif
http://www.chevellepages.com/numbers...ng_Numbers.htm
http://nastyz28.com/sbchevy/bbparts1.html

Re: Block Casting Numbers
 

Joe,

I followed the link - but I don't believe it. I've never
seen an '854 used in a 454 application. Colvins books don't
even mention the '854 as a 454 and most consider these the bible.

I'll look into it some more and get back to you. Got my
curiousity peaked https://www.yenko.net/ubbthreads/imag...mlins/hmmm.gif

Steve