Double Rectangle(?) head casting marks - The 1947 - Present Chevrolet & GMC Truck Message Board Network

1969 GMC · 03-19-2003, 11:30 PM

my GMC's engine has the double rectangle casting marks on the heads. my dad said this shouldn't be the one on my engine. I found a pic that describes all casting marks and gives numbers, mine is given as 3986388. I searched this # a few times and always the results give me contradictory info as to what they came on. Does anyone know?

btw, its supposedly the original 350...according to p/o.

1969 GMC · 03-20-2003, 12:36 AM

no one?

**breeh** · 03-20-2003, 01:01 AM

3986388....68-76...307/350

bigjimzlll · 03-20-2003, 01:22 AM

www.mortec.com

1969 GMC · 03-20-2003, 01:44 AM

thanks guys!

now, are these the original heads? and, how good are they? thanks again!

**too much stuff** · 03-20-2003, 12:45 PM

According to my book, they came off a 69-79 truck, 350 cu in. As far as the year, under the valve cover is another casting # Should be a letter for month, ( A=jan, B=feb etc.) next numbers, day of month, last digit is year. If the last digit is a 9, you will have to determine if it is 69 or 79. Hope this helps.

03-19-2003, 11:30 PM	#1
1969 GMC Registered User Join Date: Feb 2003 Location: The Rubber City Posts: 5,498	Double Rectangle(?) head casting marks my GMC's engine has the double rectangle casting marks on the heads. my dad said this shouldn't be the one on my engine. I found a pic that describes all casting marks and gives numbers, mine is given as 3986388. I searched this # a few times and always the results give me contradictory info as to what they came on. Does anyone know? btw, its supposedly the original 350...according to p/o. Attached Images __________________ 1969 GMC K2500 1996 Honda Accord 2007 Kawasaki KLR 650

03-20-2003, 12:36 AM	#2
1969 GMC Registered User Join Date: Feb 2003 Location: The Rubber City Posts: 5,498	no one? __________________ 1969 GMC K2500 1996 Honda Accord 2007 Kawasaki KLR 650

03-20-2003, 01:01 AM	#3
breeh Recovering 67-72 Addict Join Date: Oct 2000 Location: North Bend, WA Posts: 1,788	3986388....68-76...307/350 __________________ 68 Short Fleet 4x4; 427; BTO Level 3 700R4; NP205; Dana 60 front and rear; 4" lift with 35's; Disc brakes; AGR variable ratio steering; factory bucket seats; factory tach and tilt. "Friends call me cruzer cuz I like fast cars and fast women"

03-20-2003, 01:22 AM	#4
bigjimzlll Senior Member Join Date: Dec 2001 Location: Redding,CA...USA Posts: 4,736	www.mortec.com __________________ It's called "drag racing" if they called it "tic..tic..WHAM!..BANG! F*&K!!!", they'd have to keep the magazines under the counter with the other men's publications click the clicky to join the site.... http://67-72chevytrucks.com/vboard/payments.php 67 lwb..first hotrod in 25 years..540 best ET is 9.45 @ 141.44 Anderson,CA

03-20-2003, 01:44 AM	#5
1969 GMC Registered User Join Date: Feb 2003 Location: The Rubber City Posts: 5,498	thanks guys! now, are these the original heads? and, how good are they? thanks again! __________________ 1969 GMC K2500 1996 Honda Accord 2007 Kawasaki KLR 650

03-20-2003, 12:45 PM	#6
too much stuff Roadtrip! Join Date: Feb 2003 Location: Grand Rapids MN Posts: 13,712	heads According to my book, they came off a 69-79 truck, 350 cu in. As far as the year, under the valve cover is another casting # Should be a letter for month, ( A=jan, B=feb etc.) next numbers, day of month, last digit is year. If the last digit is a 9, you will have to determine if it is 69 or 79. Hope this helps.



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