Not sure if this is in the correct category so please move it if so. I purchased a complete motor today, carb to pan knowing the casting and heads were somewhat rare.

The block has a casting of 3999289 4 bolt main with the pad stamped
T0417CRR G E1189

The date code on the block is B 3 72

Here's my question...in all the books and data I have read through the CRR suffix is specific to a 70 LS6 454 SHP turbo 400 car, but obviously the date codes are not correct. Is this a replacement block for a 70 car? Or am I missing something? Any help would be appreciated.

Engine
Transmission
Notes
Code
Size-Carb
HP-RPO
CAH250-1110Manual-3Low Compression EngineCBA250-1 Manual-3/4A.I.R./Smog CAM (Calif), NB2CBD250-1 Manual-3A.I.R./Smog CAM (Calif), taxi NB2CBG250-1110Manual-3 CBJ250-1110Powerglide CBK250-1110PowerglideTaxiCDL250-1110PowerglideA.I.R.CDM250-1110StandardA.I.R.CSD250-1 PowerglideA.I.R./Smog CAM (Calif), NB2CAY307-2 Manual-3/4A.I.R./Smog CAM (Calif), NB2CAZ307-2 PowerglideA.I.R./Smog CAM (Calif), NB2CKG307-2130Standard CKH307-2130Powerglide CMA307-2 TH-350A.I.R./Smog CAM (Calif), NB2CTK307-2130TH-350 CAR350-2165-L65TH-350A.I.R./Smog CAM (Calif), Police NB2CDA *350-2165-L65Manual-3/4A.I.R./Smog CAM (Calif), NB2CDB **350-2165-L65PowerglideNB2CDD *350-4175-L48TH-350A.I.R./Smog CAM (Calif), NB2CDG350-4175-L48Manual-3/4A.I.R./Smog CAM (Calif), NB2CKA *350-2165-L65Manual-3/4 CKB *350-2165-L65TH-350 CKD *350-4175-L48TH-350 CKK350-4175-L48Manual-4 CMD *350-2165-L65TH-350A.I.R./Smog CAM (Calif), NB2CSH350-2165-L65TH-350PoliceCTL *350-2165-L65TH-350 CLA402-4240-LS3Manual-4 CLB *402-4240-LS3TH-400 CLS402-4240-LS3Manual-3 CTA402-4240-LS3Manual-3/4A.I.R./Police - TaxiCTB *402-4240-LS3TH-400A.I.R.CTJ402-4240-LS3TH-400A.I.R./Police - TaxiCPA454-4270-LS5Manual-3/4 CPD *454-4270-LS5TH-400 CRW *454-4270-LS5TH-400A.I.R.CRX454-4270-LS5Manual-3/4A.I.R.
Engine production totals are listed for U.S. production only.

* Includes Monte Carlo
** Monte Carlo exclusive

A total of 21,779 6-cyl engines were reported installed in Chevelles.
A total of 562,604 8-cyl engines were installed in Chevelles and Monte Carlos; 165,706 307cid, 373,268 350cid, and 23,630 402/454cid engines. However, this does not match the total of 8-cyl cars reportedly built in the U.S. of 578,052. This is a difference of 15,488 8-cyl units with no engines.
Engines reported for the (U.S.-built) Monte Carlo (163,087) does not match the production figure of 163,085 cars. Those break down to 151,859 350cid, 9,960 402cid and 1,268 454cid engines. Seems to be 2 extra engines reported.
Chevrolet reports 584,532 transmissions on the Accumulative Production Report of July 31, 1972. This number is only for U.S.-built Chevelles. This figure does not match the total reported U.S.-built Chevelles of 584,530. This is a difference of 2 transmissions (all types) without cars to put them in. The listed transmissions for the (U.S.-built) Monte Carlo does match the 163,087 engine production but not reported model production number of 163,085.
There is no breakdown of engines or transmissions imported from Canada or installed in imported Chevelles or Monte Carlos.

CRR 1970 454 450 Chevelle LS-6 SHP

http://www.chevy-camaro.com/chevy-camaro-chevy-bb-engine-suffix-codes.asp?group=12

CRR1970Chevelle454450THLS-6 SHP
http://www.nastyz28.com/gm-chevy-codes/chevy-engine-codes-suffix-12.php


All the information I have see is clear, which is the confusing part. I really don't think the block is a restamp and will post pics of the pad once I get if torn down a little later today. It is standard bore and a 4 bolt main block.

I think you have a replacement block, since there was no factory CRR for 1972. No LS6 for 1972, LS5 yes, so there was replacement 289 blocks for that year, but check the letters again, it should say CE, not GE.

It is a LS-6 crate motor. GM made them into the early 70's. 289 block replaced the 512

Also reported to be found in some jet boats of that early-70's era too, probably from crates as Albert has suggested....

Below are the pics of the pad. I will be taking it to the machine shop in the a.m. to mag and clean it up. It is a super nice block and excited about the opportunity to see it back in someones LS-6 car as originally intended. The crank was marked 7416 and the rods were 7/16" dimple.

http://i629.photobucket.com/albums/uu17/bparrishlvx/100_1357.jpg

http://i629.photobucket.com/albums/uu17/bparrishlvx/100_1356.jpg

http://i629.photobucket.com/albums/uu17/bparrishlvx/100_1355.jpg

http://i629.photobucket.com/albums/uu17/bparrishlvx/100_1358.jpg

what year did the LS6 crate motors switch to the XAA suffix?

what year did the LS6 crate motors switch to the XAA suffix?

What an incredible LS6 you have Mr 4 Speed!!! The color is perfect!

Got the block back from the machine shop, No ridge line at the top of the deck, bore is .30 over and will be perfect with a powerhoan, rods cleaned, pistons cleaned, block cleaned and magged, no sleeves no welding no repairs.....

Not sure if I will keep it or sell it as I have another 289 motor already built with forged 496 rotating assembly and worked 990 heads on pallet shrink wrapped for next project.

thanks for the kind words bparrishlvx :)

what year did the LS6 crate motors switch to the XAA suffix?
It should have a XAA code, NOT a CE code. CE coded engines ONLY went through service, as a replacement engine, usually changed under warranty.

When they started offering these crate engines, the first ones were coded as original stampings,
EX: CRR, then they changed over to a new code in the late '70's, XAA for a LS-6, XCH for a LS-7.
Back in the early '90's, when they were tooling the new blocks, they put these engines on sale.

A LS-7 was available for $2200-2400 depending on dealer, while the LS-6 was $2400-2600.
The LS-6 was more, as it was more streetable.
Because the casting date is like 1972, and the LS6 and LS7 crate engines are XAA and XCH respectfully .... :yes: Sooooooo, using theory, which I say is a good thing, when used in moderation, and logic ..... my assumption would be that it's a crate engine.
Plus, production engines through like 1978 only used the C and T based suffixes ....
A lot of the "CRR" crate motors through the 1970's and 80's found their way into jet and drag boats as factory installs. The #512 was used from 69 through 71, the #289 casting was then used through 77 or 78, then the #445 casting was used for quite a while after that. I may be off a little on these dates but I think I'm close ... Chances are if it has a "CRR" stamped on the serial pad, its probably a factory crate replacement motor.
XAA is GM speak for LS6 crate motor. XCH was LS7 .... :DThe engine stamp above the timing cover reads TAO1XAA8 - this XAA block casting is 14015445. It is a High Performance LS6
about 1973 Chevrolet went with the open chamber design on the crate LS6 motors.
First they used 482 open chamber heads and later 990 heads.
... and they all had that XAA suffix
Mine had the 188 heads,and the XAA suffix.
Tom The code stamped on my 1990 LS-6 crate engine is TK04XAA9,
I think the XAA part indicates LS-6 crate engine.

The engine is a big block with the following numbers TF21XAA7.
I was told by the seller it was a LS6 motor.
I have one of those 454 LS6 crate motors. My code is TD17XAA9 and is located above the timing chain cover.
Can some one tell me what the numbers mean?
I have seen codes where the suffix begins with an X, XAA = LS6; XCH = LS7.
I just think you have a service parts engine that is not documented anywhere, could have been used for non-automotive applications like irrigation pumps, generators, space shuttle.
GM has sold millions of engines to those applications.

from the "How to Hot Rod BB Chevys", HP books. It was first published in the 1970's.
The LS-7 crate motor was listed as follows:
PN 3965774, 454CID, 12.25:1 compression, 4 bolt main block, 5140 forged steel crank, w/cross-drilled mains 3963524, 4340 forged steel connecting rods with 7/16 in. bolts for pressed pins, 3963552, forged high dome pistons, racing mechanical camshaft 3959180 (same as ZL-1), open chamber cast iron heads 6260482, balancer 3963530, standard flywheel 3993827, engine suffix XCH.

Listed as 465BHP, also noted was a chevy open plenum intake. 1/16th inch compression rings. Another description in the book shows 12.5:1 compression and floating wrist pins, not pressed as described in the crate motor. So there are some conflicts in features depending on what you read.
Funny you should say that, as I bought mine about 10 yrs. ago completely disassemble and never fired.
#959 block cast June 6 1976
#990 heads cast May 4/5 1976
timing cover May 27
3530 balancer
#3524 5140 crank
assembly date July 21 1976.

http://www.chevelles.com/showroom/data/500/medium/100_5439.JPG
The LS-7 crate motor definitely was available until its discontinuance(along with the LS-6) sometime around '90-'91. It had 12.25:1 compression and the (solid lifter) cam specs were 262/273 dur. at 0.050, with lift at .580/.620. The block would've been stamped XCH.
It appears, date codeing on the XAA/XCH crate engines, changed sometime during the crate motor era.
T = Towanda
Letter = Month .... possibly.
Numbers = Day .....possibly.
XAA = LS6 crate engine suffix code
Number = Year .....possibly.

Although I don't know, "what year the LS6 crate motors switched to the XAA suffix code" ......

After having the block cleaned up you can see the serial number now...although faint you can see a "M" between the G and E.

I am going to list the block, crank, pistons, rods for sale next week... just to many motors and projects in the garage and need the space.

http://i629.photobucket.com/albums/uu17/bparrishlvx/100_1381.jpg

http://i629.photobucket.com/albums/uu17/bparrishlvx/100_1383.jpg

Interesting....

It appears, date codeing on the XAA/XCH crate engines, changed sometime during the crate motor era.
T = Towanda
Letter = Month .... possibly.
Numbers = Day .....possibly.
XAA = LS6 crate engine suffix code
Number = Year .....possibly.

Although I don't know, "what year the LS6 crate motors switched to the XAA suffix code" ......

Just for clarity of detail. XAA is a code for a 10.2 / 1 compression crate engine. GM substituted 118 CC Open Chamber Rect Port Heads on the XAA crate motors to get compression down to 10.2. Internally the XAA motors are exactly the same as the earlier higher compression LS6 motors. The only exception I can find in my engine is the change to the open chamber heads. Pistons, rods, crank and cam are identical between the XAA crate motors and the earlier LS6 configuration. I bought my engine new so I am sure it is as built by GM without any chance of anyone messing around with head substitutions.

FWIW and to add further confusion if possible. In 1971 the LS6 in the Corvette was spec'd at 9.1 / 1 compression. This was achieved with the combination of the open chamber rectangle port heads and a new smaller dome on the piston.

FWIW and to add further confusion if possible. In 1971 the LS6 in the Corvette was spec'd at 9.1 / 1 compression. This was achieved with the combination of the open chamber rectangle port heads and a new smaller dome on the piston.

:yes:

71 Corvette LS6 had a .095 tall dome
1970 Chevelle LS6 and all XAA crate motors had a .270 tall dome

Pad reads CME1189..could it be a marine app??,,M being boat-marine use?..and the C E chevrolet engine?..lots of motors wind up in boats..just a crazy thought

nice block....seeing the vanilla milkshake in my one year old 496 I may be interested in acquiring that jewel if possible. or even another of your less valuable options if available....from one "sin city" (phenix city, al) to another......