Why a steel crank? - The 1947 - Present Chevrolet & GMC Truck Message Board Network

NewKid · 05-22-2006, 11:44 AM

I have been to Pauls Gmc RPO indicator page as well as Mortec and have been in contact with ED at Mortec And have been reading other stuff about how steel forged crankshafts were not used in 240 - 250 H.P. engines. The # on the block is V0703YV For a "68" 327 and is a 3914678 block. According to the above it is supposed to be a 250 H.P. motor, so why is there a steel forged crankshaft 4672X in this motor? Everything that I have read

points to cranks of this type were supposed to be used in no less than 300 or more H.P. Does Anyone have a clue about this? Thanks

jhow66 · 05-22-2006, 12:05 PM

Probably had the crank replaced.

NewKid · 05-22-2006, 01:10 PM

Thanks for the thought. I don't know about that. This engine hasn't been taken apart before. It had been sitting out of the truck for a long time. It appeared that the distributor busted the gear. I know that it sounds hard to beleive but this still has the original intake manifold gasket on it. And the pan gaskit looked to be an original as well. The heads are what I expected with the valve covers off, pretty much choked with black burnt crud. I guess what you thought might be a good guess but I don't think so. Thanks again for the thought. Oh it does rotate.

junkyardjohn · 05-22-2006, 01:20 PM

ALOT COULD HAVE HAPPENED IN 38 YEARS

JOHN

**PICKMUP** · 05-22-2006, 01:54 PM

GM also put them in truck motors...more abuse, harder pulling, etc. They are usually found in 67-8 GM trucks.

NewKid · 05-22-2006, 02:16 PM

Thanks \Pickmup. Not trying to start anything with anyone. Just curios because it also came with the 307 327 heads. 3911032 with a right angle casting identifier on top of the head. 70 cc chamber instead of the usual 64 or 74cc. Also canister style oil filter mount not spin on. Was this normal? Date code F268Thanks John

bucket · 05-22-2006, 06:06 PM

my 67 327 has the original forged crank in it. As pickmup said, I believe it has to do with the "heavy duty" factor.

**clay68c10** · 05-22-2006, 06:26 PM

The couple of small journal small blocks I've ran into had forged cranks. One was a low-power 283. I heard somewhere all the small journal stuff had forged cranks.....

bucket · 05-22-2006, 06:29 PM

interesting. i think the 68 327 is a large journal?

jacobs · 05-22-2006, 07:53 PM

I purchased a new 1969 c20 in 1969 with the optional HD350 engine. It had a factory installed forged steel crankshaft AND heardened valve seats. This option cost about $50 over the price of the standard 350.

GM also had a option for propane. These engines had hardened valve seats but the purchaser had to purchase and install the propane system after delivery.

taylorde · 05-22-2006, 08:12 PM

I have a 69 c-10 with a 307 that has the forged crank. also with the 327 heads factory. (3rd owner)

67_C-30 · 05-22-2006, 11:56 PM

What you have is probably a leftover/changeover motor. I lot of early '68 327's were still small journal engines. The cannister style filter is a dead giveaway. I had '68 Camaro with a factory numbers matching 210 HP 327 and it was a small journal 327. All of the small journal motors had steel cranks. The SJ motors are good motors, just make sure you have the rods fitted with ARP bolts if you build it because they are 11/32" instead of the 3/8" ones used in LJ motors.

67_C-30 · 05-23-2006, 12:05 AM

No, correction! I'm wrong. Your crank is in fact listed as large journal. I'm not surprised though, I've seen all kinds of crazy stuff from GM over the years. I worked on my uncle's '76 Pontiac Grand Prix one time, and it had the head casting numbers on one head ground off and stamped on. He bought the brand new, and have never any major engine work.

3914672....327.......forged..medium journal...3.25" stroke

NewKid · 05-23-2006, 09:44 AM

Thanks All for the input. Very Nice. I guess maybe I should be called misfit instead of newkid. Thanks again John

70rs/ss · 05-23-2006, 11:30 AM

I sold one to qksilver and it was dead original with the date coded GM bearings in it and it was a 68 327, low output with a forged crank. I really wanted to make a 302 out of it, but sold the whole thing to qksilver

64fleetside · 05-23-2006, 11:56 AM

I had a 75 y/o engine builder tell me he had never seen a cast 327 crank-he knew they were listed in the catalog, but that's it. brian

67_C-30 · 05-23-2006, 10:03 PM

I have 2 of them. Both are '69 model engines.

NewKid · 05-24-2006, 12:27 PM

just a note though about this is that this crank does not have the 391 prefix as noted by 67-c-30. The number is 4672 with an X stamped into the crank right after the number. Thanks to all for the comments. John

NewKid · 05-24-2006, 12:27 PM

just a note though about this is that this crank does not have the 391 prefix as noted by 67-c-30. The number is 4672 with an X stamped into the crank right after the number. Thanks to all for the comments. John

PanelDeland · 05-24-2006, 05:02 PM

Maybe it's a factory replacement crank,installed when the truck was fairly new.Just a thought.The X in the # would seem to support that.I beleive GM used that to denote replacement parts in some instances.

7387chevys · 10-31-2006, 08:42 PM

I thought (heard somewhere ) that the X were pre production test pieces
Shane

05-22-2006, 11:44 AM	#1
NewKid Registered User Join Date: Aug 2005 Location: OCEAN SHORES WASHINGOTN Posts: 57	Why a steel crank? I have been to Pauls Gmc RPO indicator page as well as Mortec and have been in contact with ED at Mortec And have been reading other stuff about how steel forged crankshafts were not used in 240 - 250 H.P. engines. The # on the block is V0703YV For a "68" 327 and is a 3914678 block. According to the above it is supposed to be a 250 H.P. motor, so why is there a steel forged crankshaft 4672X in this motor? Everything that I have read points to cranks of this type were supposed to be used in no less than 300 or more H.P. Does Anyone have a clue about this? Thanks

05-22-2006, 12:05 PM	#2
jhow66 Registered User Join Date: Jun 2002 Location: Knoxville Tenn. Posts: 3,058	Re: Why a steel crank? Probably had the crank replaced. __________________ 56 Chevy Bel-Air 2dr. HT (purchased new) 71 Chevy Cheyenne SWB PU (502HO) 65 GMC short bed step--work in progress and my gofer

05-22-2006, 01:10 PM	#3
NewKid Registered User Join Date: Aug 2005 Location: OCEAN SHORES WASHINGOTN Posts: 57	Re: Why a steel crank? Thanks for the thought. I don't know about that. This engine hasn't been taken apart before. It had been sitting out of the truck for a long time. It appeared that the distributor busted the gear. I know that it sounds hard to beleive but this still has the original intake manifold gasket on it. And the pan gaskit looked to be an original as well. The heads are what I expected with the valve covers off, pretty much choked with black burnt crud. I guess what you thought might be a good guess but I don't think so. Thanks again for the thought. Oh it does rotate. Last edited by NewKid; 05-22-2006 at 01:11 PM.

05-22-2006, 01:20 PM	#4
junkyardjohn Registered User Join Date: Aug 2001 Location: SOMERSET KY. Posts: 6,425	Re: Why a steel crank? ALOT COULD HAVE HAPPENED IN 38 YEARS JOHN __________________ junkyardjohn 69 1 TON TOW TRUCK // 84 4WD CUCV BLAZER// 85 1 TON 4WD STAKE TRUCK// 86 M1031 5/4 TON 4WD CUCV// ALOT OF OLD TRUCKS FOR ONE OLD MAN TO DRIVE. THERES ROOM FOR ALL OF GODS CREATURES RIGHT NEXT TO MY MASHED POTATOES// LIFE MEMBER OF P.E.T.A (PEOPLE EATING TASTY ANIMALS) DON'T RENT U-HAUL ALWAYS TELL THE TRUTH IT WILL AMAZE PART OF THE PEOPLE & ASTONISH THE REST

05-22-2006, 01:54 PM	#5
PICKMUP "Trucks with Class" Join Date: Jul 2000 Location: OLYMPIA, WA, USA Posts: 8,158	Re: Why a steel crank? GM also put them in truck motors...more abuse, harder pulling, etc. They are usually found in 67-8 GM trucks.

05-22-2006, 02:16 PM	#6
NewKid Registered User Join Date: Aug 2005 Location: OCEAN SHORES WASHINGOTN Posts: 57	Re: Why a steel crank? Thanks \Pickmup. Not trying to start anything with anyone. Just curios because it also came with the 307 327 heads. 3911032 with a right angle casting identifier on top of the head. 70 cc chamber instead of the usual 64 or 74cc. Also canister style oil filter mount not spin on. Was this normal? Date code F268Thanks John Last edited by NewKid; 05-22-2006 at 02:18 PM.

05-22-2006, 06:06 PM	#7
bucket Registered User Join Date: Aug 2001 Location: Shawnee, KS Posts: 923	Re: Why a steel crank? my 67 327 has the original forged crank in it. As pickmup said, I believe it has to do with the "heavy duty" factor.

05-22-2006, 06:26 PM	#8
clay68c10 Senior Member Join Date: Aug 2004 Location: Centennial, CO Posts: 2,990	Re: Why a steel crank? The couple of small journal small blocks I've ran into had forged cranks. One was a low-power 283. I heard somewhere all the small journal stuff had forged cranks..... __________________ ClusterTruck: 68 C10 Bought in 89, wrecked in 03. Slow low $ rebuild started '17. 6.0 & TKO http://67-72chevytrucks.com/vboard/s...d.php?t=788602 93 K1500 Short Step, 350, NV4500, EBL flash ECU. Vortec heads & roller cam someday... 05 Jeep Wrangler Unlimited. 3” lift & 6-speed 02 E320 the insurance total “free car” 13 Tahoe LTZ

05-22-2006, 06:29 PM	#9
bucket Registered User Join Date: Aug 2001 Location: Shawnee, KS Posts: 923	Re: Why a steel crank? interesting. i think the 68 327 is a large journal?

05-22-2006, 07:53 PM	#10
jacobs Registered User Join Date: Sep 2005 Location: 9000' Mountain Man Posts: 326	Re: Why a steel crank? I purchased a new 1969 c20 in 1969 with the optional HD350 engine. It had a factory installed forged steel crankshaft AND heardened valve seats. This option cost about $50 over the price of the standard 350. GM also had a option for propane. These engines had hardened valve seats but the purchaser had to purchase and install the propane system after delivery.

05-22-2006, 08:12 PM	#11
taylorde Just A Tool Hand Join Date: Jan 2006 Location: Lovington,New Mexico Posts: 70	Re: Why a steel crank? I have a 69 c-10 with a 307 that has the forged crank. also with the 327 heads factory. (3rd owner) __________________ :hit:

05-22-2006, 11:56 PM	#12
67_C-30 I have a radical idea! Join Date: Jan 2005 Location: Sweet Home Alabama! Posts: 6,513	Re: Why a steel crank? What you have is probably a leftover/changeover motor. I lot of early '68 327's were still small journal engines. The cannister style filter is a dead giveaway. I had '68 Camaro with a factory numbers matching 210 HP 327 and it was a small journal 327. All of the small journal motors had steel cranks. The SJ motors are good motors, just make sure you have the rods fitted with ARP bolts if you build it because they are 11/32" instead of the 3/8" ones used in LJ motors. __________________ '67 C-30 Dually Pickup 6.2 Turbo Diesel, NP435 ‘72 C-10 SWB , 350 4bbl, TH350 '69 C-10 SWB , 250 L6, 3 OTT '69 GMC C3500, dump truck, 351 V6, NP435 '84 M1009 CUCV Military Blazer 67 C-30 Turbodiesel build thread http://67-72chevytrucks.com/vboard/s...d.php?t=254096 My trucks http://s226.photobucket.com/albums/d...ediafilter=all Member of the 1-Ton Club! Last edited by 67_C-30; 05-22-2006 at 11:58 PM.

05-23-2006, 12:05 AM	#13
67_C-30 I have a radical idea! Join Date: Jan 2005 Location: Sweet Home Alabama! Posts: 6,513	Re: Why a steel crank? No, correction! I'm wrong. Your crank is in fact listed as large journal. I'm not surprised though, I've seen all kinds of crazy stuff from GM over the years. I worked on my uncle's '76 Pontiac Grand Prix one time, and it had the head casting numbers on one head ground off and stamped on. He bought the brand new, and have never any major engine work. 3914672....327.......forged..medium journal...3.25" stroke __________________ '67 C-30 Dually Pickup 6.2 Turbo Diesel, NP435 ‘72 C-10 SWB , 350 4bbl, TH350 '69 C-10 SWB , 250 L6, 3 OTT '69 GMC C3500, dump truck, 351 V6, NP435 '84 M1009 CUCV Military Blazer 67 C-30 Turbodiesel build thread http://67-72chevytrucks.com/vboard/s...d.php?t=254096 My trucks http://s226.photobucket.com/albums/d...ediafilter=all Member of the 1-Ton Club! Last edited by 67_C-30; 05-23-2006 at 12:06 AM.

05-23-2006, 09:44 AM	#14
NewKid Registered User Join Date: Aug 2005 Location: OCEAN SHORES WASHINGOTN Posts: 57	Re: Why a steel crank? Thanks All for the input. Very Nice. I guess maybe I should be called misfit instead of newkid. Thanks again John __________________ 83 GMC Vandura 1 Ton 84 Chevy S-10 4x4 Durango 84 Ford 1 ton Cargo van

05-23-2006, 11:30 AM	#15
70rs/ss Registered User Join Date: Dec 2004 Location: Northern AZ Posts: 7,270	Re: Why a steel crank? I sold one to qksilver and it was dead original with the date coded GM bearings in it and it was a 68 327, low output with a forged crank. I really wanted to make a 302 out of it, but sold the whole thing to qksilver



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05-23-2006, 11:56 AM	#16
64fleetside Registered User Join Date: Apr 2004 Location: arkieland Posts: 1,070	Re: Why a steel crank? I had a 75 y/o engine builder tell me he had never seen a cast 327 crank-he knew they were listed in the catalog, but that's it. brian

05-23-2006, 10:03 PM	#17
67_C-30 I have a radical idea! Join Date: Jan 2005 Location: Sweet Home Alabama! Posts: 6,513	Re: Why a steel crank? I have 2 of them. Both are '69 model engines. __________________ '67 C-30 Dually Pickup 6.2 Turbo Diesel, NP435 ‘72 C-10 SWB , 350 4bbl, TH350 '69 C-10 SWB , 250 L6, 3 OTT '69 GMC C3500, dump truck, 351 V6, NP435 '84 M1009 CUCV Military Blazer 67 C-30 Turbodiesel build thread http://67-72chevytrucks.com/vboard/s...d.php?t=254096 My trucks http://s226.photobucket.com/albums/d...ediafilter=all Member of the 1-Ton Club!

05-24-2006, 12:27 PM	#18
NewKid Registered User Join Date: Aug 2005 Location: OCEAN SHORES WASHINGOTN Posts: 57	Re: Why a steel crank? just a note though about this is that this crank does not have the 391 prefix as noted by 67-c-30. The number is 4672 with an X stamped into the crank right after the number. Thanks to all for the comments. John __________________ 83 GMC Vandura 1 Ton 84 Chevy S-10 4x4 Durango 84 Ford 1 ton Cargo van

05-24-2006, 05:02 PM	#20
PanelDeland I am a Referee of life. Join Date: Jun 2000 Location: Greensboro N.C. Posts: 13,992	Re: Why a steel crank? Maybe it's a factory replacement crank,installed when the truck was fairly new.Just a thought.The X in the # would seem to support that.I beleive GM used that to denote replacement parts in some instances. __________________ The 47-present Chevrolet and GMC Truck Message Board Network,it's owners,moderators,members,and associates of any type should not be held responsible for my opinion. You can't fix stupid,not even with duct tape. "My appearance is due to the fact that "GOD" does punish you for having too much fun!" Barrett-Jackson has perfected alchemy,they make rust into gold! "You can lead a horse to water but you can't saddle a duck" "Cleverly disguised as a 'Responsible Adult' "Sometimes your Knight in shining armor is just a retard in tinfoil" Last edited by PanelDeland; 05-24-2006 at 05:03 PM.

10-31-2006, 08:42 PM	#21
7387chevys Registered User Join Date: Jun 2006 Location: WVa Posts: 758	Re: Why a steel crank? I thought (heard somewhere ) that the X were pre production test pieces Shane

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