67-72 Crossmember swap/Big Block frame mounts - The 1947 - Present Chevrolet & GMC Truck Message Board Network

SoCalBigBlocks · 11-17-2006, 10:44 PM

Hey People,
I am swapping an '88 Sub 3/4 ton front crossmember into a '69 factory Big Block truck. I am concerned about the shape of the late crossmember being different where the engine frame mounts bolts to it. I am either going to use the '72 only frame mount, or a '73 up frame mount. For those of you who have done it, which engine frame mounts are best to use, and does the Engine/Trans. mount correlation stay the same?

Thanks,

Tim

**53burb** · 11-18-2006, 02:16 PM

I had a question that was similiar to yours, but not exactly....here it is....http://67-72chevytrucks.com/vboard/s...d.php?t=216573 ...I was pretty sure I would get more responses than this, but maybe everybody just uses the original mounts from the 67-72...

*trkklr77* · 11-18-2006, 03:02 PM

http://67-72chevytrucks.com/vboard/s...d.php?t=214681

SoCalBigBlocks · 11-22-2006, 11:33 PM

Thanks for the input guys

qksilver · 11-23-2006, 12:23 AM

I swapped a 86 front suspension complete with the crossmember into my 69. I tried to use the 86 frame stands and they were too tall. like the frame wasn't as tall as the 86.
I had a bunch of different brackets and the 67-72 will work fine with a couple of holes drilled. I did not want to use the rare 72 bb set i had, so i used a set off on a 76 I stripped. Again only a couple of holes needed to be drilled. i did use the brace from the 86 that lays on top of the bottomframe rail.
The only real reason to swap crossmembers to me is that the oil pan is easier to remove. I would never do it again.
i would swap all the components and leave the orginal crossmember on the truck.
By using the 73-79 style brackets you can use the clam shell mounts on a big block.

*trkklr77* · 11-23-2006, 01:27 AM

"By using the 73-79 style brackets you can use the clam shell mounts on a big block."

that is one of the most important parts. i see lots of people swap in high hp bbc's and use the stock motor mounts!!! its like cutting the rope youre hanging from!!! not that a motor mount is going to get you kiiled but it just doesnt make sence. hell, my buddy is constantly trashing urithanes with a mild sbc.

11-17-2006, 10:44 PM	#1
SoCalBigBlocks Registered User Join Date: Nov 2006 Location: SoCal Posts: 47	67-72 Crossmember swap/Big Block frame mounts Hey People, I am swapping an '88 Sub 3/4 ton front crossmember into a '69 factory Big Block truck. I am concerned about the shape of the late crossmember being different where the engine frame mounts bolts to it. I am either going to use the '72 only frame mount, or a '73 up frame mount. For those of you who have done it, which engine frame mounts are best to use, and does the Engine/Trans. mount correlation stay the same? Thanks, Tim

11-18-2006, 02:16 PM	#2
53burb Senior Member Join Date: May 2004 Location: Queen Creek, AZ Posts: 1,010	Re: 67-72 Crossmember swap/Big Block frame mounts I had a question that was similiar to yours, but not exactly....here it is....http://67-72chevytrucks.com/vboard/s...d.php?t=216573 ...I was pretty sure I would get more responses than this, but maybe everybody just uses the original mounts from the 67-72...

11-18-2006, 03:02 PM	#3
trkklr77 Account Suspended Join Date: Aug 2006 Location: vacaville ca, because it as far from indy as i can be Posts: 775	Re: 67-72 Crossmember swap/Big Block frame mounts http://67-72chevytrucks.com/vboard/s...d.php?t=214681

11-22-2006, 11:33 PM	#4
SoCalBigBlocks Registered User Join Date: Nov 2006 Location: SoCal Posts: 47	Re: 67-72 Crossmember swap/Big Block frame mounts Thanks for the input guys

11-23-2006, 12:23 AM	#5
qksilver Senior Member Join Date: Dec 2004 Location: Southern Pines NC Posts: 3,853	Re: 67-72 Crossmember swap/Big Block frame mounts I swapped a 86 front suspension complete with the crossmember into my 69. I tried to use the 86 frame stands and they were too tall. like the frame wasn't as tall as the 86. I had a bunch of different brackets and the 67-72 will work fine with a couple of holes drilled. I did not want to use the rare 72 bb set i had, so i used a set off on a 76 I stripped. Again only a couple of holes needed to be drilled. i did use the brace from the 86 that lays on top of the bottomframe rail. The only real reason to swap crossmembers to me is that the oil pan is easier to remove. I would never do it again. i would swap all the components and leave the orginal crossmember on the truck. By using the 73-79 style brackets you can use the clam shell mounts on a big block. Last edited by qksilver; 11-23-2006 at 09:18 PM.

11-23-2006, 01:27 AM	#6
trkklr77 Account Suspended Join Date: Aug 2006 Location: vacaville ca, because it as far from indy as i can be Posts: 775	Re: 67-72 Crossmember swap/Big Block frame mounts "By using the 73-79 style brackets you can use the clam shell mounts on a big block." that is one of the most important parts. i see lots of people swap in high hp bbc's and use the stock motor mounts!!! its like cutting the rope youre hanging from!!! not that a motor mount is going to get you kiiled but it just doesnt make sence. hell, my buddy is constantly trashing urithanes with a mild sbc.



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