Engine mount adapter options

[glock35ipsc]

Please keep this thread specific to options available for engine mounting.

I'll start off by posting measurements and diagrams for the least expensive option: adapter plates. These plates will bolt to the LS block, and allow you to use the factory mounts that were on your SBC/BBC block, and bolt them up to the LS block.

The first diagram is a comparison of the mounting boss location on both the SBC/BBC and the LS blocks. RED is the LS mounting pattern, BLUE is the SBC/BBC pattern.

The measurements are taken from the machined bellhousing flange on the back of the block, where the transmission bolts to. From there, we measure forward to:

1] The rear bolt holes on the LS pattern, and
2] The center, or lower bolt hole of the SBC/BBC pattern.



Of the following three adapter plates in the drawing, numbers 2 and 3 are the most common.

The plates run from around $25 for 1/4" steel, up to $160 for polished aluminum. If you have access to some scrap 5/16" x 4.25" flat bar or 5/16" plate and you have a drill and a a tap & die set, they are very simple to make.

Here are the dimensions for each of the mounting configurations:



(As viewed on the drivers side of the block)


From MY experience, #2 worked best for the 73-87/91. Let me describe my original setup:

1985 GMC 1/2 ton SWB 2wd. 305/TH350C. The TH350 had a 9" tailhousing.

By using the #2 plate, all I had to do to mount the transmission (a 4L60E) was slide the trans crossmember about 2" and drill a couple holes on each side. Easy stuff.

These plates put everything in a position to where the shifter linkage was in the proper place, and the driveshaft installed without modification. I am using a mechanical clutch fan, and it sits centered front to rear, as well as up and down, within the fan shroud.

The one issue with using the #2 plates comes when you are going to use the LS's AC compressor in it's original low location. Here is the problem I ran into:



Basically, the forward ear of the adapter plate interfered with the compressor bracket. The green triangle is where the clam shell mount from the old SBC was supposed to go. I determined that moving it to the location of the red triangle would solve the problem. Then cut the excess off at the white line. Essentially, I would be modifying the #2 type plate to be just like a #3 plate.





Now everything will fit:



Then I added an extension to the engine stand so that the rubber mount would have something to bolt to:





Another option would be to add a bracket to the crossmember, and move the engine stand back about 2". Member menace121978 did this with his. He welded a piece to the crossmember. You might be able to do this with a piece of angle iron that is bolted to the crossmember as well:









Here are a few guides to use if you plan on making your own adapter plates:







Comparing the right side plate for use with and without the LS AC compressor:



Car Shop, $45.95
http://carshop.carshopinc.com/produc...id/86959/LS1GM



Swaptech multi-position plates, $99.95
http://tpiparts.net/inc/sdetail/16936



Trans Dapt through Year One, $65.95
http://www.yearone.com/serverfiles/f...hid=613AA79244



Pacific Fabrication, 4x4 crossmembers/mounts. No other info on them other than these pics:

[glock35ipsc]

Other options include a kit from BRP Muscle Rods that includes new engine stands and block mounts, transmission crossmember and mount, and mounting hardware.

$489.00

67-72: http://www.brphotrods.com/mm5/mercha...gory_Code=CNV9



73-87: http://www.brphotrods.com/mm5/mercha...ory_Code=CNV10



88-98: http://www.brphotrods.com/mm5/mercha...ory_Code=CNV11

[glock35ipsc]

Early Classic Enterprises has a kit as well that incluses rubber mounts, hardware, and appears to include stands. It is listed as a 63-72 kit.

$219.00

Go to http://www.earlyclassic.com/catalog....gory=New+Items and look for the kit on this page, or search for part number #911-GenIII.

[menace121978]

Great job Bob nice list of options there!

just something to keep in mind when picking which option your going to take... the adaptor plates modded like above (Fred Mod) have been proven that you CAN use the factory a/c compressor in the factory location on the LS engine. no need to run a high mount system with brackets, etc. etc...

[glock35ipsc]

Yeah, I guess I left that important little tidbit out!

AC compressor in it original location, no frame notching, and no aftermarket AC relocation kits required.

[foamypirate]

Good info, Bob! Thanks!

[basemodel67]

How about some info on a way to use Corvette mounts? I think they might give a little bit more room for exhaust.

[eagleuh1]

Glock35IPSC, where'd you get those AC compressor hose ends that are bolted to the compressor? I'd like something like that. Thanks.

[menace121978]

http://docsblocks.com/search.asp?pg=...=&stype=&scat=

[glock35ipsc]

Thanks brotha!

[67C10BUB]

Thanks for the info. I am currently working on putting a gen 4 5.3 in my 1968 SWB. I think I will go with the ECE system. Does anyone know if the compressor hits with these?

[Vandals909]

Anyone know the answer to 67C10BUB's question?

[68GMCCustom]

Not sure, but depending on what your setup is, the ECE kit may move the motor forward some from where it originally was. Its a very nice kit and everything fit well...I even installed the motor in the frame by myself. I have an ECE kit I've decided not to use. PM me if interested in it. I'm wanting my motor as far back as I can get it, which this kit doesn't do.

[low_84_inchaska]

i used the dirtydingo mounts from dirtydingo dotcom

[74project]

hello Sir~

Im having trouble finding out if I my cross member will be in the way with the 5.3 in a 4x4? I found the right mounts through dirty dingo that im going to get but there is still alot of things that are holding me up. If you ever come to vegas email me.

[85burb]

Originally Posted by low_84_inchaska

i used the dirtydingo mounts from dirtydingo dotcom

Did the dirtydingo mount keep the engine in factory location i can not look at the pic.

[67C10BUB]

Originally Posted by Vandals909

Anyone know the answer to 67C10BUB's question?

I went with the ECE kit and the AC compressor does clear the frame. See my build thread for specifics.

[RocketKing]

These are 6 cyl mounts in the rear holes on the frame. I used the same adapters as glock and trimmed the passenger side in order to make the A/C work. We added 2" of extra metal on the mount and then redrilled the new hole 1 3/4" from the original. Thought you might like the photos and thanks glock for the ideas!



backside



clearance



with A/C

[Critter]

Anybody ever used these?

I think the adjustable aspect of it would be nice for me. I plan leave my np205 in place and work forward from there with my nv4500 and LQ4 so I'm not exactly sure where everything will fall. My calculations show it will fall somewhere in the realm of all the adapters posted above but I'm not 100% positive where.

[85burb]

I am using these ones from dirty dingo. They say they are made for 73-87 trucks. They say 2 inches back and one inch forward of factory location. I hope to paint and install and mesure mine maybe tomarrow. They also raise the engine 1/2 inch too.

[85burb]

Here they are installed will get measurements next week.

[shenk10]

So which adapter plates do you guys think would be the best for my setup. I am not going to have the ac compressor and would like the engine in the original location. I am also going to run electric fans so I'm not worried about the mech. fan either. For glock and dennis are the modifications to the crossmember just so you can run the ac compressor in the factory location?

[1BadAction]

Originally Posted by 85burb

Here they are installed will get measurements next week.

Burb, Looks nice, how do they look installed?

[85burb]

Originally Posted by 1BadAction

Burb, Looks nice, how do they look installed?

I put them all the way forward and seems to me that it is within a 1/8 inch of factory sbc position. I had thoughts of flipping them around and checking that way. Not sure if that would work but seems to me 1/8 in going to be just fine. Dont acctually remember what way it is off tho.

[mcbassin]

Thanks Bob for putting this thread together and everyone else that contributes to it.
I found some good info here!