finding engine size - The 1947 - Present Chevrolet & GMC Truck Message Board Network

kelvin8417 · 09-23-2002, 09:25 PM

I'm new on here, iv'e been looking around serveral weeks.
My question is: how do I tell what displacement inline-six engine we have. it's a '68 GMC 3/4 ton (C20 equivilent in a chevy) I don't have the options plate on it.
any input would be appreciated

minibike · 09-23-2002, 11:03 PM

I'm not positive, but I believe mine had the displacement cast into the side of the block...

**'68OrangeSunshine** · 09-25-2002, 05:21 AM

230s were rarely if ever optioned in pick-ups. Most got 250s or 292s. A C/2500 (GMC eq for Chevy's C/20) would most likely be produced with a 292 if it was an L- six. GMC also had some big V-6s.
292s are 1.75" taller than 250s in block deck height. A 292s side lifter panels are about 4 1/2" tall and a 250s are about 3". 292s have an asymetrical mount system. The pass side engine mount is forward of the fuel pump, and the driver's side mount is in mid block. On the 250 the mounts are even with each other in the middle and the fuel pump is forward.
Your VIN # will start out CS___ if it was originally an L-6, but it won't tell your displacement.

kelvin8417 · 09-28-2002, 03:00 PM

do you know where it would be stamped on the block? Also, it is not modified in any way, it has a 4 speed manual tranny; what kind of gas mileage can I expect?
Thanks!

09-23-2002, 09:25 PM	#1
kelvin8417 Registered User Join Date: Sep 2002 Location: South Georgia farm Posts: 3	finding engine size I'm new on here, iv'e been looking around serveral weeks. My question is: how do I tell what displacement inline-six engine we have. it's a '68 GMC 3/4 ton (C20 equivilent in a chevy) I don't have the options plate on it. any input would be appreciated

09-23-2002, 11:03 PM	#2
minibike Registered User Join Date: Jun 2002 Location: Lafayette, LA Posts: 500	I'm not positive, but I believe mine had the displacement cast into the side of the block... __________________ 69 SWB LT1/4L60E www.classicplace.com

09-25-2002, 05:21 AM	#3
'68OrangeSunshine Senior Member Join Date: Feb 2002 Location: Tucson, AZ USA Posts: 7,513	230s were rarely if ever optioned in pick-ups. Most got 250s or 292s. A C/2500 (GMC eq for Chevy's C/20) would most likely be produced with a 292 if it was an L- six. GMC also had some big V-6s. 292s are 1.75" taller than 250s in block deck height. A 292s side lifter panels are about 4 1/2" tall and a 250s are about 3". 292s have an asymetrical mount system. The pass side engine mount is forward of the fuel pump, and the driver's side mount is in mid block. On the 250 the mounts are even with each other in the middle and the fuel pump is forward. Your VIN # will start out CS___ if it was originally an L-6, but it won't tell your displacement. __________________ Every 25 years I like to rebuild that 292, whether it needs it or not. Last edited by '68OrangeSunshine; 09-25-2002 at 05:25 AM.

09-28-2002, 03:00 PM	#4
kelvin8417 Registered User Join Date: Sep 2002 Location: South Georgia farm Posts: 3	do you know where it would be stamped on the block? Also, it is not modified in any way, it has a 4 speed manual tranny; what kind of gas mileage can I expect? Thanks!



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