Bolting in a '81 front suspension. Can I use the '81 motor mount towers? - The 1947 - Present Chevrolet & GMC Truck Message Board Network

REPO1 · 10-07-2003, 12:00 PM

I got a complete front suspension out of a '81 1/2 ton. I plan on completely rebuilding it, then bolting it into my '70 frame. What I am wondering is if I still need to use my original towers that go from the cross member to the upper portion of the frame, or do I use the newer towers that are on the '81 frame?

I am running a big block, if that matters. Also what motor mounts to use?

REPO1 · 10-07-2003, 11:09 PM

Anyone?

Tx Firefighter · 10-08-2003, 12:27 AM

Yes you can, but.....

The motor mount brackets will stick up above the top of the frame a little. Just fill the gap with washers or spacers of some kind and use longer bolts to compensate. If you don't understand what I'm saying, just do the swap and it will be very obvious to you. It will take you about 5 minutes to overcome. No sweat.

Kevin

REPO1 · 10-08-2003, 09:41 AM

But is this something I would want to do? Are the motor mounts in the newer trucks better? Or should I just stick to the ones I have?

Tx Firefighter · 10-08-2003, 09:43 AM

MY opinion, the later ones are more durable. They are also much cheaper. The earlier B.B. ones are getting pricey nowdays.

Kevin

REPO1 · 10-08-2003, 09:53 AM

That is what I kinda thought. I just wanted to make sure on here that I could & should do this before I went and actually did it.

I wasn't sure if it mattered with a BB or not.

Thanks!

zyggy72 · 10-08-2003, 09:56 AM

From what I've experienced for small block trucks the newer style motor mounts let the engine torque a bit more but it is easier and faster to replace where as the older style motor mounts let the motor torque very little, they are tighter but it takes longer and are harder to replace. If your '70 truck was a factory big block then this may not be the case.

junkyardjohn · 10-08-2003, 12:07 PM

I PUT A FRONTEND ASSY. OUT OF A 75 I/2 TON BB TRUCK IN A 71. I USED THE TOWERS OUT OF THE 75 WITH NO FITMENT PROBLEMS AT ALL. I DID HAVE TO DRILL ONE HOLE. I INSTALLED A 1970 454. NOW I HAVE USED LATE MODEL BB TOWERS WITH 71 OR 72 CROSSMEMBERS, & THE TOWERS DID STICK UP ABOVE THE FRAME RAILS ABOUT 3/8" OF AN INCH, & DID REQUIRE SPACERS BETWEEN THE TOP OF THE FRAME RAILS & THE ENGINE TOWER. JOHN

REPO1 · 10-08-2003, 01:37 PM

Thanks for the info John.

My truck is originally a BB, but the '81 I am getting the front suspension out of is a small block. Does this make a difference? From what I have heard, it doesn't, and the only difference between the BB and the SB is the actual motor mount.

Is this correct?

tom hand · 10-08-2003, 02:41 PM

As far as I know, the mounts are the same too. The 73 up mounts are similar in design to 72 BB mounts and much better than 67-71 BB mounts....not to mention cheaper

junkyardjohn · 10-08-2003, 02:46 PM

I BELIEVE YOU ARE RIGHT. I THINK THE ONLY DIFERENCE IN THE LATER MODEL TRUCKS BETWEEN SBs & BBs IS THE MOTOR MOUNTS & MAYBE THE COIL SPRINGS. IT'S A PRETTY STRAIT FORWORD SWAP. GOOD LUCK JOHN

10-07-2003, 12:00 PM	#1
REPO1 Shortbox wanna-be. Join Date: Mar 2002 Location: Fort St.John, British Columbia, Canada Posts: 773	Bolting in a '81 front suspension. Can I use the '81 motor mount towers? I got a complete front suspension out of a '81 1/2 ton. I plan on completely rebuilding it, then bolting it into my '70 frame. What I am wondering is if I still need to use my original towers that go from the cross member to the upper portion of the frame, or do I use the newer towers that are on the '81 frame? I am running a big block, if that matters. Also what motor mounts to use? __________________ 1970 Chevy C20 Custom Camper 402BB Turbo 400 trans. (Slowly becoming a '70 shortbox 1/2 ton) '71 Camaro SS 402/T400 resto '97 Z28 (11.41@127MPH)

10-08-2003, 12:27 AM	#3
Tx Firefighter Watch out for your cornhole ! Join Date: Jun 2003 Location: Azle, Texas Posts: 14,162	Yes you can, but..... The motor mount brackets will stick up above the top of the frame a little. Just fill the gap with washers or spacers of some kind and use longer bolts to compensate. If you don't understand what I'm saying, just do the swap and it will be very obvious to you. It will take you about 5 minutes to overcome. No sweat. Kevin __________________ I'm on the Instagram- @Gearhead_Kevin

10-08-2003, 09:43 AM	#5
Tx Firefighter Watch out for your cornhole ! Join Date: Jun 2003 Location: Azle, Texas Posts: 14,162	MY opinion, the later ones are more durable. They are also much cheaper. The earlier B.B. ones are getting pricey nowdays. Kevin __________________ I'm on the Instagram- @Gearhead_Kevin

10-08-2003, 12:07 PM	#8
junkyardjohn Registered User Join Date: Aug 2001 Location: SOMERSET KY. Posts: 6,425	I PUT A FRONTEND ASSY. OUT OF A 75 I/2 TON BB TRUCK IN A 71. I USED THE TOWERS OUT OF THE 75 WITH NO FITMENT PROBLEMS AT ALL. I DID HAVE TO DRILL ONE HOLE. I INSTALLED A 1970 454. NOW I HAVE USED LATE MODEL BB TOWERS WITH 71 OR 72 CROSSMEMBERS, & THE TOWERS DID STICK UP ABOVE THE FRAME RAILS ABOUT 3/8" OF AN INCH, & DID REQUIRE SPACERS BETWEEN THE TOP OF THE FRAME RAILS & THE ENGINE TOWER. JOHN __________________ junkyardjohn 69 1 TON TOW TRUCK // 84 4WD CUCV BLAZER// 85 1 TON 4WD STAKE TRUCK// 86 M1031 5/4 TON 4WD CUCV// ALOT OF OLD TRUCKS FOR ONE OLD MAN TO DRIVE. THERES ROOM FOR ALL OF GODS CREATURES RIGHT NEXT TO MY MASHED POTATOES// LIFE MEMBER OF P.E.T.A (PEOPLE EATING TASTY ANIMALS) DON'T RENT U-HAUL ALWAYS TELL THE TRUTH IT WILL AMAZE PART OF THE PEOPLE & ASTONISH THE REST

10-08-2003, 02:41 PM	#10
tom hand CCRider Join Date: Feb 2000 Location: Olive Branch,MS,USA Posts: 2,232	As far as I know, the mounts are the same too. The 73 up mounts are similar in design to 72 BB mounts and much better than 67-71 BB mounts....not to mention cheaper __________________ 72 GMC Sierra SWB almost finished---- 84 Softail Olive Branch MS

10-07-2003, 11:09 PM	#2
REPO1 Shortbox wanna-be. Join Date: Mar 2002 Location: Fort St.John, British Columbia, Canada Posts: 773	Anyone?

10-08-2003, 09:41 AM	#4
REPO1 Shortbox wanna-be. Join Date: Mar 2002 Location: Fort St.John, British Columbia, Canada Posts: 773	But is this something I would want to do? Are the motor mounts in the newer trucks better? Or should I just stick to the ones I have?

10-08-2003, 09:53 AM	#6
REPO1 Shortbox wanna-be. Join Date: Mar 2002 Location: Fort St.John, British Columbia, Canada Posts: 773	That is what I kinda thought. I just wanted to make sure on here that I could & should do this before I went and actually did it. I wasn't sure if it mattered with a BB or not. Thanks!

10-08-2003, 09:56 AM	#7
zyggy72 Can't kick the addiction! Join Date: Jan 2002 Location: Riverton, CT 06065 Posts: 402	From what I've experienced for small block trucks the newer style motor mounts let the engine torque a bit more but it is easier and faster to replace where as the older style motor mounts let the motor torque very little, they are tighter but it takes longer and are harder to replace. If your '70 truck was a factory big block then this may not be the case.

10-08-2003, 01:37 PM	#9
REPO1 Shortbox wanna-be. Join Date: Mar 2002 Location: Fort St.John, British Columbia, Canada Posts: 773	Thanks for the info John. My truck is originally a BB, but the '81 I am getting the front suspension out of is a small block. Does this make a difference? From what I have heard, it doesn't, and the only difference between the BB and the SB is the actual motor mount. Is this correct?

10-08-2003, 02:46 PM	#11
junkyardjohn Registered User Join Date: Aug 2001 Location: SOMERSET KY. Posts: 6,425	I BELIEVE YOU ARE RIGHT. I THINK THE ONLY DIFERENCE IN THE LATER MODEL TRUCKS BETWEEN SBs & BBs IS THE MOTOR MOUNTS & MAYBE THE COIL SPRINGS. IT'S A PRETTY STRAIT FORWORD SWAP. GOOD LUCK JOHN __________________ junkyardjohn 69 1 TON TOW TRUCK // 84 4WD CUCV BLAZER// 85 1 TON 4WD STAKE TRUCK// 86 M1031 5/4 TON 4WD CUCV// ALOT OF OLD TRUCKS FOR ONE OLD MAN TO DRIVE. THERES ROOM FOR ALL OF GODS CREATURES RIGHT NEXT TO MY MASHED POTATOES// LIFE MEMBER OF P.E.T.A (PEOPLE EATING TASTY ANIMALS) DON'T RENT U-HAUL ALWAYS TELL THE TRUTH IT WILL AMAZE PART OF THE PEOPLE & ASTONISH THE REST

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