block id help - The 1947 - Present Chevrolet & GMC Truck Message Board Network

**michael bustamante** · 03-06-2011, 07:50 PM

Posted via Mobile Device
long time no hear guyss! Need halls help decoding a block. My computer use is bill for a while. Cast # 3959512. Back of block. On the front is CE3P21032 and next to that is S0521XCB. thanks guys
mike
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**too much stuff** · 03-06-2011, 07:59 PM

The casting number isn't showing for me. What is it? Big, small, 6 cyl?

**DANTIP** · 03-06-2011, 08:02 PM

Looks like a 327 replacement engine, see below.

The 512 block was a service replacement block.Some had date codes as late as 69 or70. Some,I've been told were large journal,so be careful there. We've used them in our 327 stockers, and they do show up from time to time,so they aren't that rare if your search is diligent enough.The oil filter area is machined for a screw on filter(68 on), and some of the features on the block resemble early large journal 350 blocks. Chevrolet used to offer three stages of replacement engine- a fitted block,which came with the block,main bearings,pistons,pins,and rings with cam bearings already installed. A partial engine was a short block,sometimes with a camshaft and timing gears and cover installed,and a complete engine came with the short block,oil pump,pan,heads,valve train and covers installed.It's possible that 512 blocks came in all three configurations. The 512 is a good part if you can find it,other than the small journal crank diameter, there is probably not much advantage to scouring the earth to find one. A large journal 327 can use the stronger 350 rod forgings and 350 010/020 blocks are still much more common.

**michael bustamante** · 03-06-2011, 10:35 PM

Dantip. Man that's some good info! I was told its a small journal 327 out of a 63 vette. I got just as the block only. How can I tell a large journal from a small?
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**DANTIP** · 03-06-2011, 10:54 PM

I think the block will be large journal if the oil-filter is a spin-on (both happened in '68 if my memory serves me right).

Livrat · 03-06-2011, 10:57 PM

My sources say

#3959512 = 1962-63 327cu 250hp (which would be a small journal)

CE3P21032.. The "CE" normally denotes a service replacement engine..

The dealer/installer must of stamped "S0521XCB" as service blocks are not stamped with the date and vehicle installed info ...

The "CB" = 1963 283 m/t, police, h/p - - - impala

**DANTIP** · 03-06-2011, 11:09 PM

Quote:

Originally Posted by Livrat

My sources say

#3959512 = 1962-63 327cu 250hp (which would be a small journal)

CE3P21032.. The "CE" normally denotes a service replacement engine..

The dealer/installer must of stamped "S0521XCB" as service blocks are not stamped with the date and vehicle installed info ...

The "CB" = 1963 283 m/t, police, h/p - - - impala

I saw the 62-63 327/250 hp reference but when I the CE, I recalled the 3959512 was the casting of choice for thousands replacement 327 engines. I have owned several CE 3959512 blocks.

Livrat · 03-06-2011, 11:21 PM

DANTIP,
I did a bit more research and found out you are correct!!
Plus you are also correct on 68 being the first of the large journal 327's and a spin on oil filter..

#3959512, 1962-67 327. Was also used for some replacement blocks up to 1969."
I guess the only way we will know for sure about journal size on the engine in question is the date code.

Just curious do you know if the later 3959512 service blocks lost the oil draft tube hole/casting at the back of the block in the valley?

This is one of the reasons I like this site... I learn something new all the time!!

**too much stuff** · 03-06-2011, 11:32 PM

Heck i am just soaking it all in here. At least i know why i can't find the casting number. Good job mark and dan!

**michael bustamante** · 03-07-2011, 01:52 AM

Yeah thanks guys. You were a great help. Since its a replacement block. Do you guys think its worth rebuilding? New pistons crank heads etc? I wanted the 327 for my 67. Or would I be better off rebuilding a 350? Will this 327 be just as good as an original 327?
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ETsC10 · 03-07-2011, 02:25 AM

Quote:

Originally Posted by michael bustamante

Yeah thanks guys. You were a great help. Since its a replacement block. Do you guys think its worth rebuilding? New pistons crank heads etc? I wanted the 327 for my 67. Or would I be better off rebuilding a 350? Will this 327 be just as good as an original 327? Posted via Mobile Device

What year of truck? Are you sure it was a transplant?

(I have a bit of a prejudiced view on all 327's though. I own one (1968 LJ)
so I tend to always say keep it!)

BTW- My 1968 327 came stock with a canister filter.
I had to buy the spin-on adapter.

**michael bustamante** · 03-07-2011, 02:58 AM

Ill have to look at the block in the morning to see about the oil filter.
Posted via Mobile Device

03-06-2011, 07:50 PM	#1
michael bustamante Senior Member Join Date: Sep 2007 Location: Albuquerque NM Posts: 7,832	block id help Posted via Mobile Device long time no hear guyss! Need halls help decoding a block. My computer use is bill for a while. Cast # 3959512. Back of block. On the front is CE3P21032 and next to that is S0521XCB. thanks guys mike Posted via Mobile Device __________________ 1967custom

03-06-2011, 07:59 PM	#2
too much stuff Roadtrip! Join Date: Feb 2003 Location: Grand Rapids MN Posts: 13,715	Re: block id help The casting number isn't showing for me. What is it? Big, small, 6 cyl? __________________ 67 gmc custom lwb dakota truck. Sold...And bought back 69 swb 4x4 project (in progress) 70 c-10 lwb texas truck 70 4x4/BB/bkts/posi/tach(retired) 70 swb (wifes) 70 jimmy camper 71 K-5 factory 2wd 71 cheyenne 4x4/tach/posi/ plow rig 71 Cheyenne20 BB, buckets, tach, tilt, 4 speed 72 jimmy CST wyoming rig 72 jimmy Colorado rig 72 lifted texas 4x4 3/4 ton burb 65 fury conv. 383/auto 65 chrysler 300 "L" 413 auto

03-06-2011, 10:35 PM	#4
michael bustamante Senior Member Join Date: Sep 2007 Location: Albuquerque NM Posts: 7,832	Re: block id help Dantip. Man that's some good info! I was told its a small journal 327 out of a 63 vette. I got just as the block only. How can I tell a large journal from a small? Posted via Mobile Device __________________ 1967custom Last edited by michael bustamante; 03-06-2011 at 10:36 PM.

03-06-2011, 10:54 PM	#5
DANTIP Registered User Join Date: Sep 2001 Location: Fort Wayne, Indiana, USA Posts: 1,880	Re: block id help I think the block will be large journal if the oil-filter is a spin-on (both happened in '68 if my memory serves me right).

03-06-2011, 10:57 PM	#6
Livrat Member #1049 Join Date: Jun 2000 Location: Troy Montana Posts: 3,940	Re: block id help My sources say #3959512 = 1962-63 327cu 250hp (which would be a small journal) CE3P21032.. The "CE" normally denotes a service replacement engine.. The dealer/installer must of stamped "S0521XCB" as service blocks are not stamped with the date and vehicle installed info ... The "CB" = 1963 283 m/t, police, h/p - - - impala

03-06-2011, 08:02 PM	#3
DANTIP Registered User Join Date: Sep 2001 Location: Fort Wayne, Indiana, USA Posts: 1,880	Re: block id help Looks like a 327 replacement engine, see below. The 512 block was a service replacement block.Some had date codes as late as 69 or70. Some,I've been told were large journal,so be careful there. We've used them in our 327 stockers, and they do show up from time to time,so they aren't that rare if your search is diligent enough.The oil filter area is machined for a screw on filter(68 on), and some of the features on the block resemble early large journal 350 blocks. Chevrolet used to offer three stages of replacement engine- a fitted block,which came with the block,main bearings,pistons,pins,and rings with cam bearings already installed. A partial engine was a short block,sometimes with a camshaft and timing gears and cover installed,and a complete engine came with the short block,oil pump,pan,heads,valve train and covers installed.It's possible that 512 blocks came in all three configurations. The 512 is a good part if you can find it,other than the small journal crank diameter, there is probably not much advantage to scouring the earth to find one. A large journal 327 can use the stronger 350 rod forgings and 350 010/020 blocks are still much more common. Last edited by DANTIP; 03-06-2011 at 08:09 PM.

03-06-2011, 11:21 PM	#8
Livrat Member #1049 Join Date: Jun 2000 Location: Troy Montana Posts: 3,940	Re: block id help DANTIP, I did a bit more research and found out you are correct!! Plus you are also correct on 68 being the first of the large journal 327's and a spin on oil filter.. #3959512, 1962-67 327. Was also used for some replacement blocks up to 1969." I guess the only way we will know for sure about journal size on the engine in question is the date code. Just curious do you know if the later 3959512 service blocks lost the oil draft tube hole/casting at the back of the block in the valley? This is one of the reasons I like this site... I learn something new all the time!! Last edited by Livrat; 03-06-2011 at 11:21 PM.

03-06-2011, 11:32 PM	#9
too much stuff Roadtrip! Join Date: Feb 2003 Location: Grand Rapids MN Posts: 13,715	Re: block id help Heck i am just soaking it all in here. At least i know why i can't find the casting number. Good job mark and dan! __________________ 67 gmc custom lwb dakota truck. Sold...And bought back 69 swb 4x4 project (in progress) 70 c-10 lwb texas truck 70 4x4/BB/bkts/posi/tach(retired) 70 swb (wifes) 70 jimmy camper 71 K-5 factory 2wd 71 cheyenne 4x4/tach/posi/ plow rig 71 Cheyenne20 BB, buckets, tach, tilt, 4 speed 72 jimmy CST wyoming rig 72 jimmy Colorado rig 72 lifted texas 4x4 3/4 ton burb 65 fury conv. 383/auto 65 chrysler 300 "L" 413 auto

03-07-2011, 01:52 AM	#10
michael bustamante Senior Member Join Date: Sep 2007 Location: Albuquerque NM Posts: 7,832	Re: block id help Yeah thanks guys. You were a great help. Since its a replacement block. Do you guys think its worth rebuilding? New pistons crank heads etc? I wanted the 327 for my 67. Or would I be better off rebuilding a 350? Will this 327 be just as good as an original 327? Posted via Mobile Device __________________ 1967custom

03-07-2011, 02:58 AM	#12
michael bustamante Senior Member Join Date: Sep 2007 Location: Albuquerque NM Posts: 7,832	Re: block id help Ill have to look at the block in the morning to see about the oil filter. Posted via Mobile Device __________________ 1967custom



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