84Cutlass Supreme 5.3LS swap challenges.

krav84

Not-quite-so-new-guy
May 7, 2021
18
3
Hey guys, , im fairly new to the LS swap thing. I bought a couple 5.3 truck vortec/LS engines, one a fairly complete cutout , the other not so much.
Then i found a 84 Cutlass in good shape , almost zero rust on frame or body. Entire underside was undercoated a long time ago it seems. Most everything works in the car with exception of wiper pump and side marker lights. It ran pretty decent with a 305 4bbl at least once warm but it was weak. So i bought it with hopes of putting one of my LS motors in it.

Already pulled out the 305 about 2 weeks ago and got the LS attached to th350 and wedged back in the car. It was a very tight fit w/o taking off either the intake or crank pulley but i got it in there.
Now the problems started;
First off the podoy engine mounts looked just like lsx innovations so i thought they would work. Well, they dont, truth be told i dont think the lsx innovation ones would either. Not sure what happened when the stock 307 was pulled and this 305 was put in?

I could only get one or the other mount bolted together with clamshells off the 305, the other mount was 2/3 of bolthole off.
Being that the LS is gonna TQ ccw and pull away from drivers side mount i chose to use that mount as is and remove passenger mount and fab a pushup bracket spacer under frame mount. [after 5-10 hrs of jacking, fabbing, rejiggering i thought i had it done.]

But going to put in the manifolds was a deal breaker even with drivers side sitting lower than passneger and turning the manifold more into open space between ls block and frame rails, the collector of manifold is right up against the frame and brake manifold which also has gear shifting bracket mounted to it.
So realising this isnt going to work anyways, i leveled the engine hanging off my 2 ton hoist, and now i have to fab a new mount spacer bracket on drivers side. ONLY THIS ONE has to be much stronger as the motor will TQ away and pull on it for rest of its life in the car.
PLUS i now have to cut the collector off the stock manifold entirely, clock it backwards about 2 hrs and cut a wedge out so that it points closer to transmission and existing hole.

as is the engine seems to be closer to passenger side by about 0.5 to maybe 1 inch and tailshaft of transmission seems to be exactly centered so that means its probly out of wack a couple degrees longitudanaly which would help it fit better but i cant move the rear of block any closer to the passenger side as valve cover is already hitting heater box. so to straighten it out that 2 degrees i would need to scrap the 10 hrs work i did on passenger mount and start all over rebuilding new mounts ALL with engine in the way.

Does anyone else here have experience with mounts in Gbody swap?
if so, did the mounts you bought bolt right up?
if so did the manifolds also bolt right up?
any bright ideas from guys who have done this exact swap?
 

krav84

Not-quite-so-new-guy
Thread starter
May 7, 2021
18
3
Thats helpful. So far i disagree, its neither cheap , nor easy.
the engines were cheap to buy YES
but im looking at spending almost as much JUST on the fuel system, then there will be new rad hoses needed, new custom power steering hoses, steamline fitting adapters, motor mounts plural since first ones dont work, then probly electric fans since the fan sits another 1.5 inches away from rad, completely new exhaust system{quoted $950] , new throttle cable, maybe new kickdown transmission cable too, then VATs removal fee, tuning fee, [or buy Hp tuners$400 usd]
plus $400 for new engine hoist /engine leveler, engine lift plate, and thats just the stuff i know of so far.

then theres all the time i spent so far on just effing with mounts that dont work and all future time fabbing up , transmission mounts, fabbing custom drivers side exhaust manifold that fits or buy S10 headers and HOPE THEY FIT

you ever done an LS Swap in a gbody? or one at all?
Sounds like you musta paid someone to do it for you......
 
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motorheadmike

Geezer
Nov 18, 2009
7,308
113
Ottawa, Ontario Canada
Fill your boots:


 

Jakefromstatefarm

Master Mechanic
Feb 26, 2014
385
93
I'm headed down this road soon...

Little worried what I will find...

My car started as a V8 car, but when someone put in a SBC they welded the mounts to the cross member... So I will have to see if the location will work or if I will need to cut them off and relocate them to the appropriate position which I have no idea where the correct position is since there is 23 bolt openings for the mounts
 

Injectedcutty

G body LS mafia
Supporting Member
Nov 24, 2014
5,792
113
Louisville, KY
I'm headed down this road soon...

Little worried what I will find...

My car started as a V8 car, but when someone put in a SBC they welded the mounts to the cross member... So I will have to see if the location will work or if I will need to cut them off and relocate them to the appropriate position which I have no idea where the correct position is since there is 23 bolt openings for the mounts
No need to remove the sbc mounts if they're in the stock location. The lower front part of the mount should be hanging off the crossmember, only 3 bolts hold it to the frame.

I'm using ICT billet swap plates with stock engine side mounts for sbc cars. Using a G force crossmemver for the 4L80E. It's close to the firewall, but clears. I'm out here right now clay barring so pics are from a min ago....
20210507_222505.jpg
20210507_222516.jpg
 

Jakefromstatefarm

Master Mechanic
Feb 26, 2014
385
93
No need to remove the sbc mounts if they're in the stock location. The lower front part of the mount should be hanging off the crossmember, only 3 bolts hold it to the frame.

I'm using ICT billet swap plates with stock engine side mounts for sbc cars. Using a G force crossmemver for the 4L80E. It's close to the firewall, but clears. I'm out here right now clay barring so pics are from a min ago....
View attachment 174912 View attachment 174913
I don't think they are in the stock location... Let me snap a pic real quick.

But again, I am uncertain.

I plan to go from the 355 SBC with the TH350 to LQ4 with TH400.
 

Jakefromstatefarm

Master Mechanic
Feb 26, 2014
385
93
I ran down to the garage to compare to your photos .. they might be in the stock location but I think they are slightly off because the bolt holes aren't clear to be able to bolt them down if I wanted to.... So that was my reason for thinking they are not in stock locations, but the may be very close
IMG_20210507_214032.jpg
IMG_20210507_214056.jpg
 
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