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Need help please / 1956 365 block with two different heads casting #s

Started by Popsashburn, September 12, 2017, 08:47:30 PM

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Popsashburn

I've got a 1956 365 motor.(block number 1463376)  I pulled the valve covers and have two different head casting numbers.
Left - 1465406-7
Right - 1462983-4
I also noticed the push rods and the lifters are different as are the rocker arms
Left head has solid push rods and no oil holes in the rocker arms and are 9 3/4" long
Right head has hollow rods, oil holes in the rockers and are 9 1/2" long.

My question??  Can I run these two sets of rockers together and if so, would they run 9 3/4" rods?
I understand Cadillac made two different motors in 1956 with possibly two different cams??
Are the heads compatible? 
Thank you in advance.  Hugh

Lexi

I am not the best to answer this one, but the following link may provide some assistance for starters-so I pass it on for what its worth. I believe your car has both generations of cylinder heads that were produced that year. In the link provided note that there is also a discussion of push rods for the 365 c.i. engine. Curiously, a friend of mine has a '56 which had a noisy valve train (and damaged hardened valve seats). The engine re-builder said that his push rods were 1/4 inch in length out, (wrong size). This was done by a previous re-builder. Seems to mirror one of your comments, though I don't know what generation of heads were in his car, nor for that matter whether the push rods were even Cadillac. All of this tells me that one has to be extremely careful when conducting cylinder head work with this year of Caddy. While the site Administrator observed that the Master Parts List noted that '56 appeared to be a stand alone year for the rods, mismatching them could be an issue under certain scenarios, (at least with different years). I have a Motors Manual from 1958 which also contains interchange information and it also cites 1956 push rods as stand alone. Anyhow, have a look at this link  for more details and be sure to enlarge and read the bulletin and related information pages that were posted, for additional cautionary advice and clarity. Please let us know what you discover! Clay/Lexi
http://midcenturycadillacs.com/index.php?topic=3339.0

Lexi

Almost forgot, but the MPL only lists one block for 1956, but 2 different camshafts. Clay/Lexi

Popsashburn

Clay/Lexi.   Thank you for that link.  I think I will join over there to continue this search.  I have scoured many bits of info, and made several phone calls, to no end.   This info is getting very close!
I need to make sure I get the proper lifters and push rods, and also make sure my two rocker arm assemblies will both work.    Thank you again.  Hugh

cadman56

When I rebuilt my last 1956 365 V8 I still owned a parts store.  The late 56 engine used a different valve lifter and push rod set up than the earlier engines.  HoLarrywever the rocker arms were the same.  And the parts were less expensive.
I used the later lifter/push rod set up and the engine rand perfectly.
Perhaps your engine may have a head replaced and some time and who ever did the rework could not locate the earlier lifter and push rod set.
The difference is the push rod seat in the later lifter sets higher in the lifter body, thus recquiring a shorter push rod.  But the puds were still solid with no center openings.
Larry
1956 Cadillac Coupe deVille (sold)
1956 Cadillac Convertible (sold)
1956 Cadillac Eldorado Seville (sold)
1967 Cadillac Eldorado (sold)
1968 Cadillac Convertible (Sold)
1991 Cadillac Fleetwood Brougham dElegance
Larry Blanchard CLC #5820

Lexi

Hi Larry. That is what I thought, however why would the Master Parts book only list ONE set of push rods for 1956 Cadillac heads? It does not specify that 2 different length push rods as being available. Clay/Lexi

Popsashburn

I believe the block and driver side head are the later 1956 parts. The passenger side "replacement" head, I believe is the earlier 1956 head/push rods/ lifters.
I think I'll try and purchase a complete set of late 1956 lifters and push rods. I believe they are the 9 3/4" rods. (9.765) . 
I'm still a bit confused about the rocker arms.  Original (driver side) head has solid rods and no oil hole in rockers.  The "replacement" head, had hollow rods and oil holes in the rockers??

Popsashburn

I might be completely backwards on which is early and late 56' heads here too? 

Lexi

My understanding is the casting #1462983 represents the early head. Clay/Lexi