72 4x4 burb - The 1947 - Present Chevrolet & GMC Truck Message Board Network

DBear · 12-02-2008, 03:16 AM

i have a 72 4X4 BURB and my ? is ....on the front of the , there are 4 holes where the engine crossmember can be bolted on. it seems that there are 4 there so you can pull the motor forward or backward???? does anyone know the correct bolt placement for a k5 with a 350. on mine, the were mounted in the back two holes, which seemed to make the motor too far back in to the firewall. maybe the rear two holes are for a 6 cylinder????? PLEASE HELP

1956cameo · 12-02-2008, 10:02 PM

I am completely guessing but maybe the 4x4 trucks have the engine in a different location due to needing more room for the transfer case? Sorry I can't help but I am sure someone on here can.

70rs/ss · 12-03-2008, 01:00 PM

It takes 4 bolts per side to hold the crossmember on? I am guessing you mean there are 6 holes in the frame, and yes the 4X4 mount the V8 in the rear position, hense the 4X4 shroud being so huge and long! You can easily move the motor to the forward position if you want, but be aware you may need to shorten the front shaft and get a longer rear driveshaft if you move it too much. I'd guess a 1/2-3/4" you could get away with and it shouldn't cause too much headache with the driveshafts?? My Blazer has the BBC mounted in the rear position and the motor is tight but still fits against the firewall with no real issues.

justcuz · 12-03-2008, 01:31 PM

I think the 4x4 are mounted further back for the front axle housing to clear the pan on full compression of the suspension. Remember the stock springs on those trucks did not have much up travel, so it was a consideration. That is probably why the early ones had those little brackets behind the shackles bolted to the bottom of the frame rail...to limit compression travel of the springs.

olblue60@aol.com · 12-26-2008, 01:54 PM

I have also noticed the difference of the exhaust manifolds. The 4x4s had a straight drop where 2wds turned back to clear the crossmember.

71swb4x4 · 12-26-2008, 02:54 PM

Yes, 4x4's did use the rear holes. On trucks with sagging body mounts it can be a real challenge to change a distributor cap if you have converted to HEI.

BigBlueBomber · 12-31-2008, 09:33 PM

I converted a 68 3/4ton 2wd to a 3/4 4x4 and used the front holes and moved the motor forward and had alot more room than on my 71. I'm not sure how hard it would be to move everything forward.

12-02-2008, 03:16 AM	#1
DBear Registered User Join Date: Nov 2008 Location: Rowlett, TX Posts: 863	72 4x4 burb i have a 72 4X4 BURB and my ? is ....on the front of the , there are 4 holes where the engine crossmember can be bolted on. it seems that there are 4 there so you can pull the motor forward or backward???? does anyone know the correct bolt placement for a k5 with a 350. on mine, the were mounted in the back two holes, which seemed to make the motor too far back in to the firewall. maybe the rear two holes are for a 6 cylinder????? PLEASE HELP

12-02-2008, 10:02 PM	#2
1956cameo Registered User Join Date: Apr 2008 Location: Angleton, TX Posts: 2,219	Re: 72 4x4 burb I am completely guessing but maybe the 4x4 trucks have the engine in a different location due to needing more room for the transfer case? Sorry I can't help but I am sure someone on here can.

12-03-2008, 01:00 PM	#3
70rs/ss Registered User Join Date: Dec 2004 Location: Northern AZ Posts: 7,271	Re: 72 4x4 burb It takes 4 bolts per side to hold the crossmember on? I am guessing you mean there are 6 holes in the frame, and yes the 4X4 mount the V8 in the rear position, hense the 4X4 shroud being so huge and long! You can easily move the motor to the forward position if you want, but be aware you may need to shorten the front shaft and get a longer rear driveshaft if you move it too much. I'd guess a 1/2-3/4" you could get away with and it shouldn't cause too much headache with the driveshafts?? My Blazer has the BBC mounted in the rear position and the motor is tight but still fits against the firewall with no real issues.

12-03-2008, 01:31 PM	#4
justcuz Registered User Join Date: May 2008 Location: Alta Loma, Ca. Posts: 930	Re: 72 4x4 burb I think the 4x4 are mounted further back for the front axle housing to clear the pan on full compression of the suspension. Remember the stock springs on those trucks did not have much up travel, so it was a consideration. That is probably why the early ones had those little brackets behind the shackles bolted to the bottom of the frame rail...to limit compression travel of the springs.

12-26-2008, 01:54 PM	#5
olblue60@aol.com member Join Date: Dec 2003 Location: Silver Spring Md.20901 Posts: 2,031	Re: 72 4x4 burb I have also noticed the difference of the exhaust manifolds. The 4x4s had a straight drop where 2wds turned back to clear the crossmember. __________________ 1967 C/K10 Chevy Panel 1968 C/K20 Chevy Pickup 1968 C/K10 Chevy Suburban 1941 Chevy Sedan Delivery 1960 Chevy Sedan Delivery 1972 Camaro SS 396 #s matching 1971 Harley FX Superglide

12-26-2008, 02:54 PM	#6
71swb4x4 Senior Member Join Date: Nov 2003 Location: Brookings, SD Posts: 10,497	Re: 72 4x4 burb Yes, 4x4's did use the rear holes. On trucks with sagging body mounts it can be a real challenge to change a distributor cap if you have converted to HEI. __________________ Some people are like slinkies, they aren't good for anything, but you can't help but smile when you see one tumble down the stairs.

12-31-2008, 09:33 PM	#7
BigBlueBomber Registered User Join Date: Nov 2008 Location: Berthoud, Colorado Posts: 9	Re: 72 4x4 burb I converted a 68 3/4ton 2wd to a 3/4 4x4 and used the front holes and moved the motor forward and had alot more room than on my 71. I'm not sure how hard it would be to move everything forward.



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