Engine decoding - The 1947 - Present Chevrolet & GMC Truck Message Board Network

Solver · 06-03-2006, 04:55 PM

Just picked up an engine for one of my trucks today. 350 engine and 350 tranny included.
Guy told me it was an 82 chevy van engine that had 82,000 miles. Told me he drove the van home an hour and it ran great. Got it off the trailer this afternoon and sprayed her down with oven cleaner and high pressure water. Got to checking the front engine pad and came up with a CMJ suffix code. Ran that and came up with this
:1974 CMJ 350 t4OO police - 4 full size
SO much for the 82 theory! really didn't care about year anyway
Any idea whether this is just a regular engine or is it something special for police cars.
Any way the process begins.
Should I put an older style intake on it without all the extra tubes and such , or just plug all the holes up.
Should I convert it over to drivers side alt?
Would you put on a standard thermostat houseing ?
Engine doesn't have to look 1972 stock just wondering what to keep and what to swap out!
any how here is the pics we all seem to crave

Sweet72 · 06-03-2006, 05:26 PM

http://www.nastyz28.com/sbchevy/spcode2.html
Did you go to this site? CMJ was also used on the 1980 305, full size/camaro. I'm wondering what the 1974 t400 police engine was too. What's the block casting number?

Sweet72 · 06-03-2006, 07:22 PM

I also found this information here http://www.chevy-camaro.com/chevy-ca...es.asp?group=2
on that suffix code CMJ

Suffix YR CI HP Main Transmission
CMJ 1975 350 145 4 THM 350/400, federal

Solver · 06-04-2006, 12:36 AM

I am sure it's a 350 not a 305 as the block is the good old 39710 Block

Gray Ghost · 06-04-2006, 01:23 AM

The 1974 police motor was an 397014 block number and the other good one is the 397010 350. I had the '74 block in the Buffalo when I had it.

Check the number behind the driver's side valve cover, If it's neither of the above, check the nastyz28 site for the code.

The front pad numbers can tell you what it originally came out of.

06-03-2006, 04:55 PM	#1
Solver Registered User Join Date: May 2000 Location: Storm Lake, Ia Posts: 1,449	Engine decoding Just picked up an engine for one of my trucks today. 350 engine and 350 tranny included. Guy told me it was an 82 chevy van engine that had 82,000 miles. Told me he drove the van home an hour and it ran great. Got it off the trailer this afternoon and sprayed her down with oven cleaner and high pressure water. Got to checking the front engine pad and came up with a CMJ suffix code. Ran that and came up with this :1974 CMJ 350 t4OO police - 4 full size SO much for the 82 theory! really didn't care about year anyway Any idea whether this is just a regular engine or is it something special for police cars. Any way the process begins. Should I put an older style intake on it without all the extra tubes and such , or just plug all the holes up. Should I convert it over to drivers side alt? Would you put on a standard thermostat houseing ? Engine doesn't have to look 1972 stock just wondering what to keep and what to swap out! any how here is the pics we all seem to crave Attached Images __________________ 1972 Cheyenne Super 20 LWB-Blue 1972 Cheyenne Super 10 LWB-Black 1972 Cheyenne Super 10 LWB-Red 1972 Cheyenne Super 10 LWB-green 1972 GMC 4x4 LWB-White 1971 Cheyenne 10 LWB-Ochre 1971 Cheyenne 20 Longhorn-Copper 1971 Cheyenne 20 Longhorn-Black 1969 Custom 10 LWB-lt blue 1968 GMC 3/4 ton-green 1968 1/2 ton swb stepside-silver 1967 Chevrolet CST 10 LWB-green 1967 Chevrolet custom 20 LWB-Maroon

06-03-2006, 05:26 PM	#2
Sweet72 Registered User Join Date: Nov 2003 Location: Alexandria, VA Posts: 1,534	Re: Engine decoding http://www.nastyz28.com/sbchevy/spcode2.html Did you go to this site? CMJ was also used on the 1980 305, full size/camaro. I'm wondering what the 1974 t400 police engine was too. What's the block casting number? __________________ '72 GMC SWB C1500 Custom, frame-off in progress. 383 SBC, 9:1CR, Comp Cams XE262H, Scat internal balanced crank, Eagle SIR 6" rods, Keith Black dish pistons, Dart Iron Eagle 72/180 heads, Weiand Stealth intake, Stewart stage I water pump, Holley 4bbl vac sec, TH350 with B&M Shift Improver Kit. 12 bolt positraction. Last edited by Sweet72; 06-03-2006 at 05:43 PM.

06-03-2006, 07:22 PM	#3
Sweet72 Registered User Join Date: Nov 2003 Location: Alexandria, VA Posts: 1,534	Re: Engine decoding I also found this information here http://www.chevy-camaro.com/chevy-ca...es.asp?group=2 on that suffix code CMJ Suffix YR CI HP Main Transmission CMJ 1975 350 145 4 THM 350/400, federal __________________ '72 GMC SWB C1500 Custom, frame-off in progress. 383 SBC, 9:1CR, Comp Cams XE262H, Scat internal balanced crank, Eagle SIR 6" rods, Keith Black dish pistons, Dart Iron Eagle 72/180 heads, Weiand Stealth intake, Stewart stage I water pump, Holley 4bbl vac sec, TH350 with B&M Shift Improver Kit. 12 bolt positraction. Last edited by Sweet72; 06-03-2006 at 07:24 PM.

06-04-2006, 12:36 AM	#4
Solver Registered User Join Date: May 2000 Location: Storm Lake, Ia Posts: 1,449	Re: Engine decoding I am sure it's a 350 not a 305 as the block is the good old 39710 Block __________________ 1972 Cheyenne Super 20 LWB-Blue 1972 Cheyenne Super 10 LWB-Black 1972 Cheyenne Super 10 LWB-Red 1972 Cheyenne Super 10 LWB-green 1972 GMC 4x4 LWB-White 1971 Cheyenne 10 LWB-Ochre 1971 Cheyenne 20 Longhorn-Copper 1971 Cheyenne 20 Longhorn-Black 1969 Custom 10 LWB-lt blue 1968 GMC 3/4 ton-green 1968 1/2 ton swb stepside-silver 1967 Chevrolet CST 10 LWB-green 1967 Chevrolet custom 20 LWB-Maroon

06-04-2006, 01:23 AM	#5
Gray Ghost Senior Member Join Date: Sep 2004 Location: Terrell, TX Posts: 1,967	Re: Engine decoding The 1974 police motor was an 397014 block number and the other good one is the 397010 350. I had the '74 block in the Buffalo when I had it. Check the number behind the driver's side valve cover, If it's neither of the above, check the nastyz28 site for the code. The front pad numbers can tell you what it originally came out of. __________________ Kelly '05 GMC Sierra SLE Z71 Bone stock except for new bed rail caps.



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