327 info needed

[STEBS]

ran the suffix code on my 68, everything is numbers matching.

question is, Its a code YL, 240hp 327. I have hunted high and low for information and specs on the the 240hp to turn up nothing.

the only real information I found is that the 240hp is RPO L30, not to be confused with the "real" L30 327.


info?

[Jrainman]

1968 YL coded 327 were used in Chevy K20 and GMC 2500 only .

[Alex V.]

Did this engine use a 4G or Quadrajet? I assume it used the 300HP cam, what about the heads and compression ratio? If I'm correct the 220HP of '67 used 1.72" valve, 68CC chamber heads with 8.5:1 compression.

[STEBS]

I just recently got the truck running and havnt really looked at the truck or (dirt covered) engine very much. I merely got it running long enough to run back and forth for parts when I blew my v6 in the 92 and swapped in a v8. And now just kind of addressing little things at a time like the radio IHOP, no headlights, etc, aswell as just extra research in general to be well knowledged in the "unique" truck I own, etc.

It does have a quadrajet on it...
suffix code V0403YL

I can tell u that the heads are not tapped for upper assessories and I recall seeing the hump markings on the side but I would have to go look again as to what formation they were.

[Jrainman]

Originally Posted by Alex V.

Did this engine use a 4G or Quadrajet? I assume it used the 300HP cam, what about the heads and compression ratio? If I'm correct the 220HP of '67 used 1.72" valve, 68CC chamber heads with 8.5:1 compression.

My 1967 327 220 hp has 3814480 heads 1.72/1.50 60cc this is SJ crank being a 67 , I am not suprised that your 68 heads are not tapped this would be the norm on a big change over year , I know the Nova had a 327 L30 option and I believe it was rated at 300 HP .My neighbor had one back in the day.

[Alex V.]

My understanding is that the L30 RPO in passenger cars was rated at 275HP - 1.94" valve, 64CC double hump heads with 10- or 10.25:1 compression, 300HP cam, and a Quadrajet. The '67-8 Corvette base 327 was essentially the same engine with only a different carburetor (Holley?) advertised as 300HP. Is it possible the 240HP truck 327 was only a 220HP with the Quadrajet upgrade? '68 Brochure lists it as 240 horse, 330 torque (up 10 from the '67 220 horse) and 8.5:1 compression, so by conjecture it seems logical the innards are closer to an up-rated 220 HP than a de-rated 275 HP.

Also, the 480 heads (which I have a set of along with a date-matched '67 "YS" suffix 220HP block) list as 70CC chambers.

[STEBS]

To make this truck a little more odd, there is NO build sticker on the glove box. Unless someone knows alternate places they may be, there is no SPID label or any indication that there was ever one. And the previous owner still kept the the "hub lock" diagram/stick er on the front of the box aswell as the 4wd shift pattern sticker/label on the driver-side roof. So I don't see him removing the SPID label

[STEBS]

[Alex V.]

If you're interesed enough to buy a set of valve cover gaskets (cork) popping one of the valve covers off will reveal the head date and casting, confirming what the heads are and if they've been changed.

[STEBS]

Originally Posted by Alex V.

If you're interesed enough to buy a set of valve cover gaskets (cork)

Why cork? After many years messing with cork, I finally switched over to the rubber permatex gaskets

[Alex V.]

Just my preference, as well as, I think, a lot of others here. At any rate, it isn't that bad to pull the VC's off to check the numbers and maybe adjust your valves while you're there, if necessary.

[STEBS]

Originally Posted by Alex V.

it isn't that bad to pull the VC's off ... and maybe adjust your valves while you're there, if necessary.

I second that notion now that u bring the matter up

[STEBS]

Havnt had more time to piddle with the 68 that much, BUT... I did clean out the glovebox hoping to maybe find an SPID sticker that just never got applied and maybe stuck in with the factory paper work. And I came across these...



I thought yall might appreciate these numbers...

[STEBS]

Another interesting thing I found was what I believe to be the "custom build plate" for the truck. I know that it was a 1 owner, and that him and his wife custom ordered this truck.

I gather this confirms that?




I can make out,

327, RXSTD. TRSM465, 0000, 4.56, KE, IDI185310, GMC4, 2OD-PB60405

[Jrainman]

Its nice to have the protecto plate and all warranty and protection Plan ..That plate is used to tranfer the truck info on to the work order when the truck was taken in for service and are warranty work.... this is my 1969 warranty

[BILT4ME]

I have read here on the forum that the 67 & 68 GMC's did NOT have a SPID. (Chevy did, GMC did not.)