Big block motor mount troubles ...... - The 1947 - Present Chevrolet & GMC Truck Message Board Network

RSRXION · 07-03-2006, 09:09 PM

OK guys here's my situation. I got the 454 all cleaned and painted today, changed the front and rear seals in the TH-400 and started prepping the hauler for the transplant. I noticed that there was a crossmember from the previously used 4 speed and removed it by grinding off the rivets. I'll be using the automatic crossmember from the 76 1 ton donor truck. Now here's my problem...

I am told that the 73-87 style big block mounts will work in this truck IF I use the the complete mount assemblys including frame mounts. I sat the frame mounts in place on the frame and the bottom holes line up perfectly with just a minor amount of adjusting required to align the top two holes. Is this going to be correct ? Will the 454 be located properly front to rear ? I've included a couple of pictures and as you can see the holes align very well with only a slight amount of adjusting required to make them fit.

I've also included a photo of the VIN tag. Do these rivets appear to be factory correct ? This tag is located down toward the bottom of the back of the drivers' door opening. If this truck is factory rated at 14,000 GVW... I'm a very happy camper ! I can put about anything I like on it without fear of an overzealous DOT inspector.

Thanks for your help guys, Dean

Oh by the way, I noticed that the block is a " Hi-Perf Pass " block. It's also a "K" block. That should mean 4 bolt I think.

**uncle** · 07-03-2006, 09:27 PM

Rivets look to have been replaced.

RSRXION · 07-04-2006, 01:16 AM

bump

chevymad · 07-04-2006, 04:21 PM

High perf pass is on all non tall deck blocks. Doesnt mean its 4 bolt. Not sure bout the K though. The few bb's i've owned have been 2 bolts with high perf pass on em. I used the entire front xmember from a 74 bb gmc along with the motor mounts on my 70 frame. Motor just clears the cab and is proper distance from radiator. Not sure if the driveline would've been right or not though, I had a driveline made to fit. I have a th400 in the truck and the tranny xmember did not line up with any of the frame holes, also the transmission linkage for the auto did not line up at all.

*1972C10* · 07-05-2006, 05:46 AM

When i did the 73-87 SB mounts on a 68 the top bolts fit i had to drill a new hole for the bottom BB Stuff is a different bird to me.

Sure thats the right tag Im assuming its for some kinda C40 Or C50 What kinda truck is that on?

RSRXION · 07-05-2006, 06:08 AM

It's a 72 C-30 . Believe it or not the tag matches the frame number. This was a factory cab and chassis that has been a 19 foot car hauler most ( if not all ) of its' life. Thanks, Dean

da-burb · 07-05-2006, 11:36 PM

I believe that is the same load limits on my 71 C30 motorhome.

RSRXION · 07-09-2006, 01:24 AM

bump ttt

Longhorn Man · 07-09-2006, 11:04 AM

those rivits are certianly not original. No way no how. However, if the number matches your chassis, then the DOT guy can't mess with you about it.
As for the high perf deal, EVERY big block made for a car or light duty truck, (as in non tall deck) said that. It means nothing, except it's a low deck motor. In a tow rig like yours, 4 bolt would mean absolutly nothing untill it was time to sell the engine. They are way over rated.
Your best bet, is to bolt down the towers or frame mounts..what ever you wanna call them, then swing the hoist over with the engine, or engine and tranny if that's how you have it hung. Drop it in there, and slide the bolts through the mounts. It is now located where it'll be as it is rigged up now. You could go as far as removing the hoist and getting it out of the way. Start checking everything, the rad and fan clearance, the shroud, find where the tranny crossmember will be, and mark to drill if need be. You can also get the numbers needed for a drive shaft. The industry standard on drive shafts, is to have the yoke slid into the tranny 50%, then measure center od U-joint hole, to center of U-joint hole. However, you get a hillbilly running your local drive shaft shop, and it could throw everything all off, so call your driveshaft place and ask how they want it measured before giving them measurements.

This may take up to a day to do this, but, when final instalation time comes up, you KNOW it'll be right.

And as a side note, in case you are unaware, the mounts you are usign there are 10 times better than the factory ones.

*rage'nrat638* · 07-09-2006, 11:14 AM

heres a picture of the solid mounts from jegs..i am using them on my mountain motor..you would need to drill the botton center hole...

http://www.jegs.com/webapp/wcs/store...tegoryId=13065

07-03-2006, 09:09 PM	#1
RSRXION Senior Member Join Date: Jun 2006 Location: Arkansas Posts: 227	Big block motor mount troubles ...... OK guys here's my situation. I got the 454 all cleaned and painted today, changed the front and rear seals in the TH-400 and started prepping the hauler for the transplant. I noticed that there was a crossmember from the previously used 4 speed and removed it by grinding off the rivets. I'll be using the automatic crossmember from the 76 1 ton donor truck. Now here's my problem... I am told that the 73-87 style big block mounts will work in this truck IF I use the the complete mount assemblys including frame mounts. I sat the frame mounts in place on the frame and the bottom holes line up perfectly with just a minor amount of adjusting required to align the top two holes. Is this going to be correct ? Will the 454 be located properly front to rear ? I've included a couple of pictures and as you can see the holes align very well with only a slight amount of adjusting required to make them fit. I've also included a photo of the VIN tag. Do these rivets appear to be factory correct ? This tag is located down toward the bottom of the back of the drivers' door opening. If this truck is factory rated at 14,000 GVW... I'm a very happy camper ! I can put about anything I like on it without fear of an overzealous DOT inspector. Thanks for your help guys, Dean Oh by the way, I noticed that the block is a " Hi-Perf Pass " block. It's also a "K" block. That should mean 4 bolt I think. Attached Images

07-03-2006, 09:27 PM	#2
uncle Senior Member Join Date: Aug 2003 Location: Conyers,Ga. Posts: 7,288	Re: Big block motor mount troubles ...... Rivets look to have been replaced.

07-04-2006, 01:16 AM	#3
RSRXION Senior Member Join Date: Jun 2006 Location: Arkansas Posts: 227	Re: Big block motor mount troubles ...... bump

07-04-2006, 04:21 PM	#4
chevymad Registered User Join Date: Jan 2001 Location: skamokawa, WA, USA Posts: 527	Re: Big block motor mount troubles ...... High perf pass is on all non tall deck blocks. Doesnt mean its 4 bolt. Not sure bout the K though. The few bb's i've owned have been 2 bolts with high perf pass on em. I used the entire front xmember from a 74 bb gmc along with the motor mounts on my 70 frame. Motor just clears the cab and is proper distance from radiator. Not sure if the driveline would've been right or not though, I had a driveline made to fit. I have a th400 in the truck and the tranny xmember did not line up with any of the frame holes, also the transmission linkage for the auto did not line up at all. __________________ 70 C10 long fleet, 355/200 4r, 6 lug disc conversion, 3" drop 70 gmc changed to 67/8 chevy, 454 with voodoo cam, th400, all 74 running gear.. in progress

07-05-2006, 05:46 AM	#5
1972C10 Account Suspended Join Date: Dec 2003 Location: Texas Posts: 2,686	Re: Big block motor mount troubles ...... When i did the 73-87 SB mounts on a 68 the top bolts fit i had to drill a new hole for the bottom BB Stuff is a different bird to me. Sure thats the right tag Im assuming its for some kinda C40 Or C50 What kinda truck is that on?

07-05-2006, 06:08 AM	#6
RSRXION Senior Member Join Date: Jun 2006 Location: Arkansas Posts: 227	Re: Big block motor mount troubles ...... It's a 72 C-30 . Believe it or not the tag matches the frame number. This was a factory cab and chassis that has been a 19 foot car hauler most ( if not all ) of its' life. Thanks, Dean

07-05-2006, 11:36 PM	#7
da-burb "Ochre Ogre" Join Date: Apr 2000 Location: Springfield, MN Posts: 3,558	Re: Big block motor mount troubles ...... I believe that is the same load limits on my 71 C30 motorhome. __________________ Bowtie Truck Stop Inc. Mid-West GM Truck Restoration Parts Supplier Your Key Parts, Auto Metal Direct, Dynacorn, and Goodmark dealer. like us @ www.facebook.com/BowtieTruckStop 1971 C-10 Suburban (Ochre) 1971 K-10 Suburban (Ochre) 1972 C-10 Suburban (Ochre) 1972 K-20 Suburban (Yellow- that just aint right!) Springfield, Minnesota 56087

07-09-2006, 01:24 AM	#8
RSRXION Senior Member Join Date: Jun 2006 Location: Arkansas Posts: 227	Re: Big block motor mount troubles ...... bump ttt

07-09-2006, 11:04 AM	#9
Longhorn Man its all about the +6 inches Join Date: Jan 2001 Location: Hilliard Ohio Posts: 2,693	Re: Big block motor mount troubles ...... those rivits are certianly not original. No way no how. However, if the number matches your chassis, then the DOT guy can't mess with you about it. As for the high perf deal, EVERY big block made for a car or light duty truck, (as in non tall deck) said that. It means nothing, except it's a low deck motor. In a tow rig like yours, 4 bolt would mean absolutly nothing untill it was time to sell the engine. They are way over rated. Your best bet, is to bolt down the towers or frame mounts..what ever you wanna call them, then swing the hoist over with the engine, or engine and tranny if that's how you have it hung. Drop it in there, and slide the bolts through the mounts. It is now located where it'll be as it is rigged up now. You could go as far as removing the hoist and getting it out of the way. Start checking everything, the rad and fan clearance, the shroud, find where the tranny crossmember will be, and mark to drill if need be. You can also get the numbers needed for a drive shaft. The industry standard on drive shafts, is to have the yoke slid into the tranny 50%, then measure center od U-joint hole, to center of U-joint hole. However, you get a hillbilly running your local drive shaft shop, and it could throw everything all off, so call your driveshaft place and ask how they want it measured before giving them measurements. This may take up to a day to do this, but, when final instalation time comes up, you KNOW it'll be right. And as a side note, in case you are unaware, the mounts you are usign there are 10 times better than the factory ones.

07-09-2006, 11:14 AM	#10
rage'nrat638 Account Suspended Join Date: Mar 2003 Location: THE FALL GUY CHICAGO IL Posts: 5,883	Re: Big block motor mount troubles ...... heres a picture of the solid mounts from jegs..i am using them on my mountain motor..you would need to drill the botton center hole... http://www.jegs.com/webapp/wcs/store...tegoryId=13065 Last edited by rage'nrat638; 07-09-2006 at 11:18 AM.



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