SBC Cylinder Head Markings - The 1947 - Present Chevrolet & GMC Truck Message Board Network

**Ironhorse** · 06-19-2024, 04:02 PM

A friend of mine just recently purchased a '72 Chevy K10 long bed 4x4. Rough in many ways but seems pretty complete. SBC which is said to be a 350 (?) but not sure on that, has 350TH trans. I haven't seen the truck yet but he sent me this pick of the head markings. Not familiar at all with this set of markings, said the dip stick is on the D/S which makes it pre-'79 if I'm remembering correct on that? Any one who can help ID this cylinder head marking for us?

**CAMAROBOY68SS** · 06-20-2024, 12:24 AM

does the head have the accessory holes or a thermostat hole in the head? that would help with narrowing down the head as it kind of looks like a 3973487 head, but it also looks like its a pre 67 head as I don't see the machined off area for accessory holes, but it could be due to all the crud on the head.

RustyPile · 06-20-2024, 07:00 PM

Remove the valve cover(s) and note the casting number(s).. Go to the website in my link and look up the number(s)....

https://outintheshop.com/faq/casting/heads.html

**Ironhorse** · 06-20-2024, 08:58 PM

Suggested that same thing to my friend and also to clean the crud off the engine markings on the right hand pad near the valve cover side. Between the markings on the cylinder head and the engine pad should tell the story. The truck is at his Father-in-Laws house, not his house. Plans to go look a bit closer at it this weekend. Will post more info as I can.

**MJN** · 06-21-2024, 08:41 AM

Here is what my book shows for those casting marks;
3998991: 307 (69-73) and 350 (73-76) Truck light duty 1.71 intake valve, 1.50 exhaust valve

468642: 350 truck (71-85), Corvette (80-85), 400 truck (75-80) 1.71 intake valve, 1.50 exhaust valve

06-19-2024, 04:02 PM	#1
Ironhorse Senior Member Join Date: Jul 2001 Location: Wellington, Ks Posts: 10,130	SBC Cylinder Head Markings A friend of mine just recently purchased a '72 Chevy K10 long bed 4x4. Rough in many ways but seems pretty complete. SBC which is said to be a 350 (?) but not sure on that, has 350TH trans. I haven't seen the truck yet but he sent me this pick of the head markings. Not familiar at all with this set of markings, said the dip stick is on the D/S which makes it pre-'79 if I'm remembering correct on that? Any one who can help ID this cylinder head marking for us? Attached Images __________________ 1971 Chevy 1/2T 4x4 LWB 350 V-8 Was sm465-now 350TH/np205 Tilt, Tach, Towhooks Original Truck AM/FM Wellington, Ks

06-20-2024, 12:24 AM	#2
CAMAROBOY68SS Senior Member Join Date: Apr 2022 Location: Hillsboro, Oregon Posts: 433	Re: SBC Cylinder Head Markings does the head have the accessory holes or a thermostat hole in the head? that would help with narrowing down the head as it kind of looks like a 3973487 head, but it also looks like its a pre 67 head as I don't see the machined off area for accessory holes, but it could be due to all the crud on the head. __________________ The Twins: 1968 C10 SWB - Blue 327/5 Speed 1968 Camaro SS/RS - Blue 327/4speed C10 Build Thread: http://67-72chevytrucks.com/vboard/s...d.php?t=833278 The "Others" 1933 Ford Pickup (Camaro in disguise) 2017 Camaro SS Life long Chevy guy

06-20-2024, 07:00 PM	#3
RustyPile Registered User Join Date: Dec 2017 Location: Elkhart, Texas Posts: 1,606	Re: SBC Cylinder Head Markings Remove the valve cover(s) and note the casting number(s).. Go to the website in my link and look up the number(s).... https://outintheshop.com/faq/casting/heads.html

06-20-2024, 08:58 PM	#4
Ironhorse Senior Member Join Date: Jul 2001 Location: Wellington, Ks Posts: 10,130	Re: SBC Cylinder Head Markings Suggested that same thing to my friend and also to clean the crud off the engine markings on the right hand pad near the valve cover side. Between the markings on the cylinder head and the engine pad should tell the story. The truck is at his Father-in-Laws house, not his house. Plans to go look a bit closer at it this weekend. Will post more info as I can. __________________ 1971 Chevy 1/2T 4x4 LWB 350 V-8 Was sm465-now 350TH/np205 Tilt, Tach, Towhooks Original Truck AM/FM Wellington, Ks

06-21-2024, 08:41 AM	#5
MJN Registered User Join Date: Feb 2000 Location: Maquoketa, Ia/ Orr, Mn Posts: 2,983	Re: SBC Cylinder Head Markings Here is what my book shows for those casting marks; 3998991: 307 (69-73) and 350 (73-76) Truck light duty 1.71 intake valve, 1.50 exhaust valve 468642: 350 truck (71-85), Corvette (80-85), 400 truck (75-80) 1.71 intake valve, 1.50 exhaust valve Attached Images __________________ '51 South Bend Model "9A" '56 Chevy 3600 NAPCO '74 Chevy Cheyenne Super K20-restored on 37's '72 GMC Sierra Custom K2500- in progress '08 GMC Envoy Denali '12 GMC Sierra 2500HD Denali '17 GMC Yukon XL VCCA member #58596 http://www.nohrco.com



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