Why a steel crank?

[NewKid]

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]

Probably had the crank replaced.

[NewKid]

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]

ALOT COULD HAVE HAPPENED IN 38 YEARS JOHN

[PICKMUP]

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

[NewKid]

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]

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]

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]

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

[jacobs]

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]

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]

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]

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]

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

[70rs/ss]

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]

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]

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

[NewKid]

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]

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]

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]

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