Question about RPO Code on Spid - The 1947 - Present Chevrolet & GMC Truck Message Board Network

**Already Gone** · 05-20-2010, 11:17 AM

I have no Spid in my truck so I contacted GM and received the package with the codes and info from when it was built. I understand all the codes except one and it shows "Z32 Rear Wheel Equip". Does anone know what that code means?

I thought it might have something to do with the spare tire and wheel but they are coded seperate as "Z33 Spare Wheel Equip" and "Z34 Spare Tire Equip"

Another question I have is that the original engine code for my truck is LS9 the 350 engine and M38 3 speed auto trans and no posi. With that combo it shows I should have the 3:73 as the standard ratio rear end with the 3:07 and 4:11 being optional. I have the 12 bolt in my truck so I am assuming I have the standard 3:73 because they'd put a 10 bolt with the 3:07 wouldn't they?

**Already Gone** · 05-20-2010, 06:26 PM

ttt

71 super · 05-20-2010, 07:25 PM

m49 was the option code for automatic, 350 or 400- if the code had a * following the m49 (m49*) I beleve it designated the 400, but both transmissions carried the same option number. m38 is the code for a standard shift three speed

**68350** · 05-20-2010, 07:29 PM

3.08(3.07) gears are standard with the TH350.

LONGHAIR · 05-20-2010, 08:23 PM

I don't know for sure on these older trucks, but in the '73-'87 generation you could actually get the "spare wheel" w/o a tire mounted. I have seen lots of them in the dealerships with a bare wheel in the undermount carrier.
I don't really know what the point of that was?

Longhorn Man · 05-20-2010, 09:58 PM

some trucks actually did get the car deignation of M38 for the TH350, either way, the 3.07 gear was standard with the TH 350 or TH 400 in a 1/2 ton 2 wheel drive.
Also, in 1/2 tons, there were no 10 bolt rears.

**Already Gone** · 05-23-2010, 12:07 PM

Quote:

Originally Posted by LONGHAIR

I don't know for sure on these older trucks, but in the '73-'87 generation you could actually get the "spare wheel" w/o a tire mounted. I have seen lots of them in the dealerships with a bare wheel in the undermount carrier.
I don't really know what the point of that was?

Yes I agree with you. I would think that is the case except I also have Z33 Spare wheel Code and Z34 Spare tire Code.

**Already Gone** · 05-23-2010, 12:13 PM

Quote:

Originally Posted by Longhorn Man

some trucks actually did get the car deignation of M38 for the TH350, either way, the 3.07 gear was standard with the TH 350 or TH 400 in a 1/2 ton 2 wheel drive.
Also, in 1/2 tons, there were no 10 bolt rears.

My truck was redone by someone long before I got it in 2001. I didnt know all the trucks came with 12 bolts and that is good to know. I think I have 3:73 gears because of the RPMS ( from a factory added tach ) at highwat speeds and the terible gas mileage. One of these days I guess I should pull the cover off the rearend and find out for sure. The truck also has a TH400 now instead of the original 350trans.

Longhorn Man · 05-23-2010, 01:01 PM

on the MPG... it's tough to get good numbers. on a poll I did on here, the majority of us are getting 10 - 12 MPG.
What kind of RPMs you turning @ 60 MPH? 2300 - 2500 (the variables are converter slippage and tire size) would indicate a 3.07 gear.

**Already Gone** · 05-23-2010, 01:50 PM

Quote:

Originally Posted by Longhorn Man

on the MPG... it's tough to get good numbers. on a poll I did on here, the majority of us are getting 10 - 12 MPG.
What kind of RPMs you turning @ 60 MPH? 2300 - 2500 (the variables are converter slippage and tire size) would indicate a 3.07 gear.

I'm running 235/70R15's on the truck and it is doing 3000/3100 RPM's at 65 MPH and yes I get 12 mpg on the highway and 10 in the city.

48richard · 05-23-2010, 03:03 PM

I also have no SPID - who did you contact to get your truck information?

Richard

**Already Gone** · 05-23-2010, 03:41 PM

Quote:

Originally Posted by 48richard

I also have no SPID - who did you contact to get your truck information?

Richard

I contacted GM in Canada. I do not know if you guys in the USA can get the same info. Below is the email address of the guy I contacted to get the info,he may be able to steer you to the right person for the USA info.

george.zapora@cc.gmccanada.com

Longhorn Man · 05-23-2010, 08:09 PM

GM didn't keep that info on US trucks, only GM of canada did

48richard · 05-24-2010, 11:13 AM

Too bad, but thanks anyway.

Richard

05-20-2010, 11:17 AM	#1
Already Gone 70+ ( Old Skool Club ) Join Date: Nov 2003 Location: Saskatoon, Saskatchewan ,Canada Posts: 9,108	Question about RPO Code on Spid I have no Spid in my truck so I contacted GM and received the package with the codes and info from when it was built. I understand all the codes except one and it shows "Z32 Rear Wheel Equip". Does anone know what that code means? I thought it might have something to do with the spare tire and wheel but they are coded seperate as "Z33 Spare Wheel Equip" and "Z34 Spare Tire Equip" Another question I have is that the original engine code for my truck is LS9 the 350 engine and M38 3 speed auto trans and no posi. With that combo it shows I should have the 3:73 as the standard ratio rear end with the 3:07 and 4:11 being optional. I have the 12 bolt in my truck so I am assuming I have the standard 3:73 because they'd put a 10 bolt with the 3:07 wouldn't they? __________________ 1972 C10 Custom/Deluxe 613 Highlander 406/700R4 1999 White Tahoe LS 4x2 with Z56 Police Package 1992 K1500 GMC Suburban Members I have personally met: MusicMan70 - HeavyD - ChewyChevy67 - StingRay -71SWB4x4 - 67 Burb - DeadheadNM - too much stuff - bc65 - das601 " Circumsatances Do Not Change Responsibility " " The Sky is not the Limit, Your Mind is." Marilyn Monroe .. RIP Charlie Watts 1941 - 2021

05-20-2010, 06:26 PM	#2
Already Gone 70+ ( Old Skool Club ) Join Date: Nov 2003 Location: Saskatoon, Saskatchewan ,Canada Posts: 9,108	Re: Question about RPO Code on Spid ttt __________________ 1972 C10 Custom/Deluxe 613 Highlander 406/700R4 1999 White Tahoe LS 4x2 with Z56 Police Package 1992 K1500 GMC Suburban Members I have personally met: MusicMan70 - HeavyD - ChewyChevy67 - StingRay -71SWB4x4 - 67 Burb - DeadheadNM - too much stuff - bc65 - das601 " Circumsatances Do Not Change Responsibility " " The Sky is not the Limit, Your Mind is." Marilyn Monroe .. RIP Charlie Watts 1941 - 2021

05-20-2010, 07:25 PM	#3
71 super Registered User Join Date: Sep 2005 Location: Canton North carolina Posts: 3,079	Re: Question about RPO Code on Spid m49 was the option code for automatic, 350 or 400- if the code had a * following the m49 (m49*) I beleve it designated the 400, but both transmissions carried the same option number. m38 is the code for a standard shift three speed __________________ 67 blue step side- bb 68 gold and white swb cst anniversary 68 custom swb hot rod Ls swap 69 swb cst 6 cylinder/ overdrive 69 black/black cst bb swb 70 orange and white cst Canada built truck swb bb 71 black and white super swb bb 71 red and white super swb 72 green and white super swb 4x4 62 nova wagon 400 series Ls swapped 68 Camaro 327/4 speed- 1 owner, original paint 66 Volkswagen bettle 69 auto stick Volkswagen Beetle

05-20-2010, 07:29 PM	#4
68350 Senior Member Join Date: Jan 2002 Location: Williston, ND Posts: 2,999	Re: Question about RPO Code on Spid 3.08(3.07) gears are standard with the TH350. __________________ 68 Chevy CST/10, 50th Anniversary, 327/th400, 373 posi, buckets 68 GMC Shortbox Stepside, 402/th400, Tilt, Tach, Bucket Seats, 3.08 Positraction 69 Chevy Camaro SS, 383, 4 speed, positraction 70 Chevy El Camino SS396, Triple Black, 454/th400, Tach 70 Chevy Shortbox Stepside 4x4, 350/th350, Tilt, Tach, Cab Lights, Bumper Guards, Tow Hooks 70 Chevy 3/4 Longbox, 350/auto, 70k, SURVIVOR 71 Chevy Blazer, CST, 350/auto 71 GMC Sierra K2500, 454, 4 speed, 4.10 posi, 37s 71 Custom/30, Open Road, 350/th400, tilt 72 Chevy Shortbox Fleetside, 496 Stroker/th400, Tilt, Tach, Bucket Seats, 3.42 Posi 72 GMC Sierra Grande 2500. 427/th400, tilt, a/c, tool and stowage, buckets/console, 3.54 posi

05-20-2010, 09:58 PM	#6
Longhorn Man its all about the +6 inches Join Date: Jan 2001 Location: Hilliard Ohio Posts: 2,693	Re: Question about RPO Code on Spid some trucks actually did get the car deignation of M38 for the TH350, either way, the 3.07 gear was standard with the TH 350 or TH 400 in a 1/2 ton 2 wheel drive. Also, in 1/2 tons, there were no 10 bolt rears.

05-23-2010, 01:01 PM	#9
Longhorn Man its all about the +6 inches Join Date: Jan 2001 Location: Hilliard Ohio Posts: 2,693	Re: Question about RPO Code on Spid on the MPG... it's tough to get good numbers. on a poll I did on here, the majority of us are getting 10 - 12 MPG. What kind of RPMs you turning @ 60 MPH? 2300 - 2500 (the variables are converter slippage and tire size) would indicate a 3.07 gear.

05-23-2010, 03:03 PM	#11
48richard Registered User Join Date: Oct 2009 Location: Phoenix, AZ Posts: 475	Re: Question about RPO Code on Spid I also have no SPID - who did you contact to get your truck information? Richard __________________ 1971 C10 Longbed, 350/TH350

05-23-2010, 08:09 PM	#13
Longhorn Man its all about the +6 inches Join Date: Jan 2001 Location: Hilliard Ohio Posts: 2,693	Re: Question about RPO Code on Spid GM didn't keep that info on US trucks, only GM of canada did

05-24-2010, 11:13 AM	#14
48richard Registered User Join Date: Oct 2009 Location: Phoenix, AZ Posts: 475	Re: Question about RPO Code on Spid Too bad, but thanks anyway. Richard __________________ 1971 C10 Longbed, 350/TH350



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