BBC to LS3 swap motor mount

Automotive powered airboat discussion.
Post Reply
User avatar
akblackdawg
Site Supporter - III
Site Supporter - III
Posts: 2969
Joined: Mon Jun 29, 2009 1:53 am
Location: Wasilla, ALASKA

BBC to LS3 swap motor mount

Post by akblackdawg »

installing a ls3 engine in boat with old style BBC mounts, what mount kit do i need for the change over, have a balistic box, and will the mount for the balistic box need changing also or do i leave it alone. i looked online at summit, and did brief search here but not sure if i am finding the correct information. thank you. Bud
:alaska: If you ain't living on the edge, you're taking up to much space.

15x8 Alumatech hull, with enclosed cab, aluminum cage, LS 3, 6.2 aluminum block ffi, 2.7 Balistic Box, sensinich superwide 3 blade. Built for year around riding in Alaska

josh_2562
Site Supporter - III
Site Supporter - III
Posts: 1521
Joined: Sun Aug 12, 2007 2:25 pm
Location: Inglis, FL 34449

Re: BBC to LS3 swap motor mount

Post by josh_2562 »

from what I have read you need the ones the will work for a sbc/bbc to ls engine. eBay has the best prices.

josh_2562
Site Supporter - III
Site Supporter - III
Posts: 1521
Joined: Sun Aug 12, 2007 2:25 pm
Location: Inglis, FL 34449

Re: BBC to LS3 swap motor mount

Post by josh_2562 »


User avatar
LoxStroker383
Southern Airboat Member
Posts: 96
Joined: Mon Dec 26, 2011 7:44 pm

Re: BBC to LS3 swap motor mount

Post by LoxStroker383 »

I got a question,

Do you prefer the softer rubber motor mounts that eat up some of the engine vibration, or the polyurethane hare plastic mounts like daystar?

I currently have the hard plastic mounts and notice al the engine vibrations, I was wondering if I go to the softer rubber ones will it help?
14x8 Diamondback, 383 Stroker, 2.38 OxBox, 80" 3 Blade NGR

Waterbugger
Southern Airboat Member
Posts: 61
Joined: Tue Nov 06, 2012 5:57 pm

Re: BBC to LS3 swap motor mount

Post by Waterbugger »

Its a Chevrolet from a 250 inline 6 thru a 572 big block motor mounts are the same. Transmission bell housing bolt pattern is the same. Its an easy swap done several in trucks, buggy's and boats first hand knowledge from actually going to different engines in various trucks and toys over the past 38 years. Ford is the only one you have to know what year, month, week, and if it was AM or PM shift when it was built to get the right part.

12PSI
Site Supporter - III
Site Supporter - III
Posts: 283
Joined: Wed Mar 05, 2014 1:33 pm
Location: Ft. Myers

Re: BBC to LS3 swap motor mount

Post by 12PSI »

Waterbugger wrote:Its a Chevrolet from a 250 inline 6 thru a 572 big block motor mounts are the same. Transmission bell housing bolt pattern is the same. Its an easy swap done several in trucks, buggy's and boats first hand knowledge from actually going to different engines in various trucks and toys over the past 38 years. Ford is the only one you have to know what year, month, week, and if it was AM or PM shift when it was built to get the right part.
That was true until the LS motors came along.

Waterbugger
Southern Airboat Member
Posts: 61
Joined: Tue Nov 06, 2012 5:57 pm

Re: BBC to LS3 swap motor mount

Post by Waterbugger »

The bell housing bolt pattern on the LS motors is the same. The flywheel pattern at the crank is different and spacing on the crankshaft is different. If you either make your own or buy the transition plate to allow the three hole bolt pattern to be used on the LS it will line up perfectly with existing motor mounts. You should not have to change engine stand or gearbox mounts. The LS will easily go in place of any chevrolet engine from a 250 six thru a 572. Put a 5.3 in a 77 cheyenne stepside 4x4 with no issues. put an old rotator gearbox used on a 383 on a 6.0 LS had to change flex plate hardware but bell housing bolt pattern fit perfect and sat on the same engine stand the 383 was on. I may have misunderstood the question, but I was under the impression it was referring to whether or not he could use the mounting plates that transition an LS block pattern to the old 3-bolt pattern and have the LS block line up on the engine stand with the gearbox mount and all remain in the same place. It should. It has worked on two boats I have worked on, both are running and have had no issues.

User avatar
akblackdawg
Site Supporter - III
Site Supporter - III
Posts: 2969
Joined: Mon Jun 29, 2009 1:53 am
Location: Wasilla, ALASKA

Re: BBC to LS3 swap motor mount

Post by akblackdawg »

josh_2562 wrote:http://www.dirtydingo.com/shop/mobile_c ... ?cPath=360
Gear box stays in same place
after ordering 2 different motor mount kits from Summit, both of which did not fit, and them telling me i either had to use a adjustable motor mount (i did not want one that slid back and fourth for adjustment) i went to dirty dingo today and ordered theirs, less money, lower shipping cost, and they are shipping today. my motor install headache should be solved in a few days when this arrives. thank you Josh for posting the link to the dingl website...hopefully i will be on the water and bear hunting next week. Bud

http://www.dirtydingo.com/shop/index.php?cPath=359_363
:alaska: If you ain't living on the edge, you're taking up to much space.

15x8 Alumatech hull, with enclosed cab, aluminum cage, LS 3, 6.2 aluminum block ffi, 2.7 Balistic Box, sensinich superwide 3 blade. Built for year around riding in Alaska

User avatar
goldhunter_2
Site Supporter - III
Site Supporter - III
Posts: 8953
Joined: Mon May 23, 2005 7:17 pm
Location: Port Saint Lucie Fl

Re: BBC to LS3 swap motor mount

Post by goldhunter_2 »

Bud,
Those are the same adapter plates I used swapping a LS into a older corvette nice heavy plates and you adjust forward or backward by which bolt hole you use (no sliding) then your BBC will bolt to the adapter plate.
.


Support our future , get a kid involved in the outdoors!!

:rebel:



.

User avatar
akblackdawg
Site Supporter - III
Site Supporter - III
Posts: 2969
Joined: Mon Jun 29, 2009 1:53 am
Location: Wasilla, ALASKA

Re: BBC to LS3 swap motor mount

Post by akblackdawg »

goldhunter_2 wrote:Bud,
Those are the same adapter plates I used swapping a LS into a older corvette nice heavy plates and you adjust forward or backward by which bolt hole you use (no sliding) then your BBC will bolt to the adapter plate.
i wasn't clear, i had a bbc, and am installing a ls3 6.2 on the stand that was build for the bbc. i believe what i have coming will work. thank you. Bud
:alaska: If you ain't living on the edge, you're taking up to much space.

15x8 Alumatech hull, with enclosed cab, aluminum cage, LS 3, 6.2 aluminum block ffi, 2.7 Balistic Box, sensinich superwide 3 blade. Built for year around riding in Alaska

One Eyed Gator
Southern Airboat Member
Posts: 1313
Joined: Wed May 30, 2007 11:33 am
Location: Ocala,Fl

Re: BBC to LS3 swap motor mount

Post by One Eyed Gator »

I just made my own. Use a pc of aluminum to make a template make it bolted to block and was long enough to mate to stand. Had 2 Stainless 3/16" plates cuts then fabricated as needed to mate to motor stand. I had about the same money in it but fits perfect and is all stainless steel. Way better than anything you can buy plus won't rust.

User avatar
digginfool
Site Supporter - III
Site Supporter - III
Posts: 2742
Joined: Wed Jun 05, 2013 3:00 pm
Location: South Florida

Re: BBC to LS3 swap motor mount

Post by digginfool »

Not sure if this is the same style engine stand but I got the adapter plate from DB and re-used the mounting plate from the BBC. I hoped you noted that the Dingo plate will not work with the low alternator mount. These didn't either. Had to fabricate a mount. Used the stock alternator mount, split it and welded a piece in to move it out for clearance.
Attachments
20160506_075047_resized.jpg
“When plunder becomes a way of life for a group of men living together in society, they create for themselves in the course of time a legal system that authorizes it and a moral code that glorifies it” - Bastiat

User avatar
akblackdawg
Site Supporter - III
Site Supporter - III
Posts: 2969
Joined: Mon Jun 29, 2009 1:53 am
Location: Wasilla, ALASKA

Re: BBC to LS3 swap motor mount

Post by akblackdawg »

the Dingo rep tells me that their bracket is built so that it will not interfere with the low mount alternator. I recall looking at it, and it looked like it will but the alternator very close to the bracket, but should be clearance. I hope so, may be another problem for me to deal with next week after the bracket comes in. Seems I buy a airboat specific build motor, and installation instructions that come for it are for comaro installation, and don't take into account the variables for airboats. Bud
:alaska: If you ain't living on the edge, you're taking up to much space.

15x8 Alumatech hull, with enclosed cab, aluminum cage, LS 3, 6.2 aluminum block ffi, 2.7 Balistic Box, sensinich superwide 3 blade. Built for year around riding in Alaska

User avatar
goldhunter_2
Site Supporter - III
Site Supporter - III
Posts: 8953
Joined: Mon May 23, 2005 7:17 pm
Location: Port Saint Lucie Fl

Re: BBC to LS3 swap motor mount

Post by goldhunter_2 »

akblackdawg wrote:
goldhunter_2 wrote:Bud,
Those are the same adapter plates I used swapping a LS into a older corvette nice heavy plates and you adjust forward or backward by which bolt hole you use (no sliding) then your BBC will bolt to the adapter plate.
i wasn't clear, i had a bbc, and am installing a ls3 6.2 on the stand that was build for the bbc. i believe what i have coming will work. thank you. Bud


I understood you the first post , these should work for you . Using those same adapter brackets I did not have any interference with accessories just for reference. Airboat engine swap an install will be much easier let us know how you make out
.


Support our future , get a kid involved in the outdoors!!

:rebel:



.

Post Reply

Return to “Automotive Power Only”