Heat Shield holes in 4x4 cab??? - The 1947 - Present Chevrolet & GMC Truck Message Board Network

**DANTIP** · 11-10-2011, 12:16 PM

Shown below is a stripped cab from a frame-up restoration of a '72 4x4. The SPID didn't have A/C listed and I was questioning the originality of the cab. The owner sent me a few pictures and it certainly looks like an original A/C cab. Upon closer inspection, I noticed holes in the cab floor on the passenger side that would have been used for a heat shield on a Big Block truck. The VIN tag is riveted to the cab with the rosette rivets and looks "original".

Assumptions:
1) The heat shield was a big-block only item.
2) High-hump trucks without the heat shield did not have the holes in the floor for the heat shield.
3) There is no other reasonable explanation for the heat shield holes other than the cab was originally on a Big Block 2WD truck.

This may not be important to too many people, but this is an expensive truck and I am willing to pay more for an original truck than one that has been put together from multiple donors.

Lastly, is there any other differences I can look for in these photos?

Thanks for your feedback!!

**D.PASSMORE** · 11-10-2011, 03:16 PM

Thoughts:

1. Maybe a PO/dealer add-on?

2. Cab availability during production at plant?

Also, I have a 72 Chev BB deluxe (rear outer light) cab in my barn, A/C, auto, high hump. I'll check it - where are the holes located?. UPDATE - if intrested: I checked the 72 Chev BB cab - holes and checked my original 72 - 4x4 cab - no holes.

BTW, I have a few sets of GM rose-bud rivits. Going to use a set for my cab conversion - from ^^ to a 72 3/4T 4x4. You can still find them. So...

Of course 72 cabs had the cab vent on driver side lower rear door pillar and no top WS Frame hump for rear view mirror install like a 71. I believe the 69-70 cabs had a different style vent on door pillar and pre-drilled holes above WS frame for mounting rear view mirror. 67-68 cabs had no vent in the door pillar and RV mirror mounted above WS upper frame too - different mounting bracket. Some one can add or correct me if I'm wrong.

If its claimed to be a high end resto - look for aftermarket hardware. That is always a tell sign...

**RenoKeene** · 11-10-2011, 04:05 PM

Thats an AC cab alright. My 70 GMC is a factory Big Block 1/2 ton AC truck an doesn't have the holes for the heat shield.

**DANTIP** · 11-10-2011, 04:38 PM

Quote:

Originally Posted by RenoKeene

Thats an AC cab alright. My 70 GMC is a factory Big Block 1/2 ton AC truck an doesn't have the holes for the heat shield.

Next question is when did the heat shield become standard equipment on the Big-Block trucks?

My original question really is "Do the heat shield holes cast much doubt on the originality of the cab?" Remember, A/C does not appear on the SPID but the owner is convinced and is claiming it is original. I personally strongly suspect the cab was changed and the VIN tag was moved to the new cab.

**leddzepp** · 11-10-2011, 04:47 PM

Dan- Are you sure those are heat shield holes? They look a little too close to the center....I am thinking the heat shield is further to the side. I do not know for sure, but I will look at my truck later tonight when I get home and see.

I believe the heat shield started in 70 or 71, but not 100% sure.

**special-K** · 11-10-2011, 04:48 PM

I'm thinking it must be a BBC cab. I don't have heat shield holes in my '72 K2500 A/C cab. I've never noticed them on any 4wds. The air conditioning would most certainly be on the SPID and if not,the truck didn't come from the factory with A/C.

**LockDoc** · 11-10-2011, 04:56 PM

-
Here is a picture from a 72 Big Block truck I am dismantling over at the salvage yard right now. It has factory air and a high hump. It is a 2WD Cheyenne/10

LockDoc

**leddzepp** · 11-10-2011, 04:57 PM

Nevermind....Leon's pic saves me from having to look.

Probably a cab swap. It is easy to get rosette rivets off of ebay to reattach a vin plate.

VA72C10 · 11-10-2011, 05:07 PM

So looks to have been put together. What an awesome cab though!!!

**RenoKeene** · 11-10-2011, 05:23 PM

I have a heat shield for mine that I got from a board member but it is straight, not bent. Is there a difference from 70 to 72? Don't mean to hi-jack but want to put the correct one on my truck.
Thanks

**Joesjunk** · 11-10-2011, 10:31 PM

Those holes should not have been there on a 4x4 cab. But then again, I have seen some odd things happen

msgross · 11-10-2011, 11:36 PM

My 68 4x4 cab had a factory bench seat and a bucket seat support brace on the bottom.

Always a chance that the factory did "whatever it takes" to build some of our trucks.

VA72C10 · 11-11-2011, 12:22 AM

Quote:

Originally Posted by msgross

My 68 4x4 cab had a factory bench seat and a bucket seat support brace on the bottom.

Always a chance that the factory did "whatever it takes" to build some of our trucks.

good point....we might not ever know for sure since the cab was blasted....

HOTFUN · 11-11-2011, 02:02 AM

Dan. Looks pretty convincing to me that this replacement cab started life as a 71-72 big block factory ac Cheyenne cab. It either has a factory tach or the turbo 400 grommet hole knocked out looking just to the right side of the brake cylinder too. I know the tach wire grommet is the top knockout for sure but without looking I believe the turbo 400 electric kickdown wire harness also passes back out from the gas pedal mounted bracket through this or one of those dimpled knockout holes for additional options. I too have also never seen a heat shield on anything but the big block 71 and 72's. Production limitations or mistakes would better be documented with tear down pictures and also is a crucial point when redoing a rare equipped, totally original frame up restoration in my experiences. Super nice cab and nothing that couldn't be corrected to make a "perfect" 100 point restored truck. Mark

HOTFUN · 11-11-2011, 11:14 PM

Well I need to back track on what that top hole is just to the right of the speedo hole. I looked at 8 different cabs on my place today and there is no rhyme or reason to what was in that top hole if it was drilled. Two trucks had a factory camper harness that a 10 guage red wire came out of that grommet. Another big block had what appeared to be two wires probably emmision relay related. Another 350 cab had nothing, and two had the emmisions full harness coming out and going to the gutter across the engine compartment. But two trucks also had factory installed tachs and one came out second hole and the other the third hole as the brake booster brace about covers the second dimple down. Just some observations. But those two holes in the lower firewall are definitely the big block only heat shield mounts.

11-10-2011, 12:16 PM	#1
DANTIP Registered User Join Date: Sep 2001 Location: Fort Wayne, Indiana, USA Posts: 1,882	Heat Shield holes in 4x4 cab??? Shown below is a stripped cab from a frame-up restoration of a '72 4x4. The SPID didn't have A/C listed and I was questioning the originality of the cab. The owner sent me a few pictures and it certainly looks like an original A/C cab. Upon closer inspection, I noticed holes in the cab floor on the passenger side that would have been used for a heat shield on a Big Block truck. The VIN tag is riveted to the cab with the rosette rivets and looks "original". Assumptions: 1) The heat shield was a big-block only item. 2) High-hump trucks without the heat shield did not have the holes in the floor for the heat shield. 3) There is no other reasonable explanation for the heat shield holes other than the cab was originally on a Big Block 2WD truck. This may not be important to too many people, but this is an expensive truck and I am willing to pay more for an original truck than one that has been put together from multiple donors. Lastly, is there any other differences I can look for in these photos? Thanks for your feedback!! Attached Images

11-10-2011, 03:16 PM	#2
D.PASSMORE One of the First Join Date: Jan 2000 Location: St. Augustine,FL. Posts: 4,055	Re: Heat Shield holes in 4x4 cab??? Thoughts: 1. Maybe a PO/dealer add-on? 2. Cab availability during production at plant? Also, I have a 72 Chev BB deluxe (rear outer light) cab in my barn, A/C, auto, high hump. I'll check it - where are the holes located?. UPDATE - if intrested: I checked the 72 Chev BB cab - holes and checked my original 72 - 4x4 cab - no holes. BTW, I have a few sets of GM rose-bud rivits. Going to use a set for my cab conversion - from ^^ to a 72 3/4T 4x4. You can still find them. So... Of course 72 cabs had the cab vent on driver side lower rear door pillar and no top WS Frame hump for rear view mirror install like a 71. I believe the 69-70 cabs had a different style vent on door pillar and pre-drilled holes above WS frame for mounting rear view mirror. 67-68 cabs had no vent in the door pillar and RV mirror mounted above WS upper frame too - different mounting bracket. Some one can add or correct me if I'm wrong. If its claimed to be a high end resto - look for aftermarket hardware. That is always a tell sign... Last edited by D.PASSMORE; 11-11-2011 at 11:38 PM.

11-10-2011, 04:05 PM	#3
RenoKeene Florida Edition Join Date: Oct 2010 Location: Fruitland Park, FL Posts: 4,021	Re: Heat Shield holes in 4x4 cab??? Thats an AC cab alright. My 70 GMC is a factory Big Block 1/2 ton AC truck an doesn't have the holes for the heat shield. Attached Images __________________ 70 GMC Short Stepside "Rose"-An American Beauty: Factory 402/TH400, AM/FM, AC, Tilt, Tach, Buckets, Posi, PS, PB, 3-5 Drop, Complete Resto-Rod 67 C-20 Slant Back Wrecker "Mad Max" 67 C-10 Ratrod "Step-N-Wolf" 71 Serro Scotty Sportsman camper "Scotty" 97 LT1 Z28 "The Hornet" Link to more pics of "Rose" http://67-72chevytrucks.com/vboard/a...p?albumid=1684 Check out my "Cheap Tricks" thread and add to it if you can, lots of good info there. http://67-72chevytrucks.com/vboard/s...d.php?t=489394

11-10-2011, 04:47 PM	#5
leddzepp Moderator Join Date: May 2007 Location: Southern Cal Posts: 19,995	Re: Heat Shield holes in 4x4 cab??? Dan- Are you sure those are heat shield holes? They look a little too close to the center....I am thinking the heat shield is further to the side. I do not know for sure, but I will look at my truck later tonight when I get home and see. I believe the heat shield started in 70 or 71, but not 100% sure. __________________ 1972 C/10 Cheyenne Super SWB. Restored, loaded, slammed. 1968 C/10 50th Anniversary LWB. Unrestored, stock, daily driver/work truck. RIP ElJay RIP 67ChevyRedneck RIP Grumpy Old Man

11-10-2011, 04:48 PM	#6
special-K Special Order Join Date: Nov 2004 Location: Mt Airy, MD Posts: 85,862	Re: Heat Shield holes in 4x4 cab??? I'm thinking it must be a BBC cab. I don't have heat shield holes in my '72 K2500 A/C cab. I've never noticed them on any 4wds. The air conditioning would most certainly be on the SPID and if not,the truck didn't come from the factory with A/C. __________________ "BUILDING A BETTER WAY TO SERVE THE USA"......67/72......"The New Breed" GMC '67 C1500 Wideside Super Custom SWB: 327/M22/3.42 posi.........."The '67" (project) GMC '72 K2500 Wideside Sierra Custom Camper: 350/TH350/4.10 Power-Lok..."The '72" (rolling) Tim "Don't call me a redneck. I'm a rough cut country gentleman" R.I.P. ~ East Side Low Life ~ El Jay ~ 72BLUZ ~ Fasteddie69 ~ Ron586 ~ 67ChevyRedneck ~ Grumpy Old Man ~

11-10-2011, 04:56 PM	#7
LockDoc The Older Generation Join Date: Aug 2006 Location: Montezuma, Iowa Posts: 25,393	Re: Heat Shield holes in 4x4 cab??? - Here is a picture from a 72 Big Block truck I am dismantling over at the salvage yard right now. It has factory air and a high hump. It is a 2WD Cheyenne/10 LockDoc Attached Images __________________ Leon Locksmith, Specializing In Antique Trucks, Automobiles, & Motorcycles (My Dually Pickup Project Thread) http://67-72chevytrucks.com/vboard/s...d.php?t=829820 - Last edited by LockDoc; 11-10-2011 at 05:03 PM.

11-10-2011, 04:57 PM	#8
leddzepp Moderator Join Date: May 2007 Location: Southern Cal Posts: 19,995	Re: Heat Shield holes in 4x4 cab??? Nevermind....Leon's pic saves me from having to look. Probably a cab swap. It is easy to get rosette rivets off of ebay to reattach a vin plate. __________________ 1972 C/10 Cheyenne Super SWB. Restored, loaded, slammed. 1968 C/10 50th Anniversary LWB. Unrestored, stock, daily driver/work truck. RIP ElJay RIP 67ChevyRedneck RIP Grumpy Old Man

11-10-2011, 05:07 PM	#9
VA72C10 VA72C10 Join Date: Mar 2008 Location: Midlothian, VA Posts: 25,269	Re: Heat Shield holes in 4x4 cab??? So looks to have been put together. What an awesome cab though!!! __________________ Looking for a 67-72 swb or blazer project in or around VA.

11-10-2011, 05:23 PM	#10
RenoKeene Florida Edition Join Date: Oct 2010 Location: Fruitland Park, FL Posts: 4,021	Re: Heat Shield holes in 4x4 cab??? I have a heat shield for mine that I got from a board member but it is straight, not bent. Is there a difference from 70 to 72? Don't mean to hi-jack but want to put the correct one on my truck. Thanks __________________ 70 GMC Short Stepside "Rose"-An American Beauty: Factory 402/TH400, AM/FM, AC, Tilt, Tach, Buckets, Posi, PS, PB, 3-5 Drop, Complete Resto-Rod 67 C-20 Slant Back Wrecker "Mad Max" 67 C-10 Ratrod "Step-N-Wolf" 71 Serro Scotty Sportsman camper "Scotty" 97 LT1 Z28 "The Hornet" Link to more pics of "Rose" http://67-72chevytrucks.com/vboard/a...p?albumid=1684 Check out my "Cheap Tricks" thread and add to it if you can, lots of good info there. http://67-72chevytrucks.com/vboard/s...d.php?t=489394

11-10-2011, 10:31 PM	#11
Joesjunk Senior Member Join Date: May 2001 Location: Independence MO. Posts: 7,689	Re: Heat Shield holes in 4x4 cab??? Those holes should not have been there on a 4x4 cab. But then again, I have seen some odd things happen __________________ 72 3/4t Custom Deluxe 402/auto 66k Original paint 71 3/4t 4x4 Custom Deluxe 10k original miles Original paint 71 3/4t Cheyenne 402 70k original paint 72 3/4t 4x4 Custom deluxe 72 3/4t 4x4 Custom deluxe 91k original paint 72 Cheyenne/30 Dually 69 Camaro SS396 4-speed 13 GMC 2500HD Duramax I bought new 05 Jeep Wrangler "Willys Edition" 12k miles (I bought new) 85 3/4 ton 4x4 Scottsdale 33k miles original paint 86 1 ton 4x4 SRW Silverado 454 restored 80 1 ton 4x4 SRW Silverado 9,434 original miles!! original paint 95 GMC 1 ton dually 4x4 my dad bought new 95 GMC 3/4 ton 4x4, regular cab 454, 31k original miles 2002 2500HD 4x4 regular cab 6.0L 67k miles 2002 2500HD 4x4 regular cab 8.1L 28k miles 2003 GMC 2500HD 4x4 regular cab Diesel 93k miles 67-72 Parts for sale

11-10-2011, 11:36 PM	#12
msgross Registered User Join Date: Jul 2006 Location: Central PA Posts: 12,201	Re: Heat Shield holes in 4x4 cab??? My 68 4x4 cab had a factory bench seat and a bucket seat support brace on the bottom. Always a chance that the factory did "whatever it takes" to build some of our trucks. __________________ The Garage: 1968 K-10 SWB - "Project Money Pit" 1996 Z-71 - "huntin rig" 1969 C-10 LWB (SOLD) "Project flip that truck or else" 1993 Passport, F@rd 1-ton (SOLD)"Project Cousin Eddie" My Garage Build "The 1,000 footer"

11-11-2011, 02:02 AM	#14
HOTFUN Registered User Join Date: Jan 2001 Location: Lincoln, Nebraska Posts: 2,144	Re: Heat Shield holes in 4x4 cab??? Dan. Looks pretty convincing to me that this replacement cab started life as a 71-72 big block factory ac Cheyenne cab. It either has a factory tach or the turbo 400 grommet hole knocked out looking just to the right side of the brake cylinder too. I know the tach wire grommet is the top knockout for sure but without looking I believe the turbo 400 electric kickdown wire harness also passes back out from the gas pedal mounted bracket through this or one of those dimpled knockout holes for additional options. I too have also never seen a heat shield on anything but the big block 71 and 72's. Production limitations or mistakes would better be documented with tear down pictures and also is a crucial point when redoing a rare equipped, totally original frame up restoration in my experiences. Super nice cab and nothing that couldn't be corrected to make a "perfect" 100 point restored truck. Mark __________________ '66 CST BBW swb fleet 327 fac ac '67 CST 4x4 swb 327 stepside project '72 Cheyenne K20 50k original '72 Cheyenne Super K20 project '73 Sierra swb 4x4 frame off in paint stage '74 Cheyenne Super swb w/16k actual '71 & 72 Cheyenne K10 4x4 swb's '70 426 HEMICUDA conv SHAKER 4 sp Dana 60 '60 Impala conv 327 PG fac ac loaded 3rd owner '72 GMC K2500 4x4 '59 Apache CST BBW fleetside swb 283 '73 ElCamino SS LS1 T56 true SS bucket tach '76 ElCamino SS 52k survivor '87 Grand National 41k True 2nd to last built in 1987. '86 K30 454 SRW fleetside CA since new '88 Trans Am GTA 39k bought new 2018 DEMON plum crazy @ 840HP! "Need for speed"

11-11-2011, 11:14 PM	#15
HOTFUN Registered User Join Date: Jan 2001 Location: Lincoln, Nebraska Posts: 2,144	Re: Heat Shield holes in 4x4 cab??? Well I need to back track on what that top hole is just to the right of the speedo hole. I looked at 8 different cabs on my place today and there is no rhyme or reason to what was in that top hole if it was drilled. Two trucks had a factory camper harness that a 10 guage red wire came out of that grommet. Another big block had what appeared to be two wires probably emmision relay related. Another 350 cab had nothing, and two had the emmisions full harness coming out and going to the gutter across the engine compartment. But two trucks also had factory installed tachs and one came out second hole and the other the third hole as the brake booster brace about covers the second dimple down. Just some observations. But those two holes in the lower firewall are definitely the big block only heat shield mounts. __________________ '66 CST BBW swb fleet 327 fac ac '67 CST 4x4 swb 327 stepside project '72 Cheyenne K20 50k original '72 Cheyenne Super K20 project '73 Sierra swb 4x4 frame off in paint stage '74 Cheyenne Super swb w/16k actual '71 & 72 Cheyenne K10 4x4 swb's '70 426 HEMICUDA conv SHAKER 4 sp Dana 60 '60 Impala conv 327 PG fac ac loaded 3rd owner '72 GMC K2500 4x4 '59 Apache CST BBW fleetside swb 283 '73 ElCamino SS LS1 T56 true SS bucket tach '76 ElCamino SS 52k survivor '87 Grand National 41k True 2nd to last built in 1987. '86 K30 454 SRW fleetside CA since new '88 Trans Am GTA 39k bought new 2018 DEMON plum crazy @ 840HP! "Need for speed"



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