98olds73

Has anyone attempted or can point me in the right direction I would like to LS swap a 6.0 in my 1973 olds 98. And was wondering if anyone has done that before with the model years 71-73 because they are the same. I’m trying to find parts to convert it over but it’s hard to find anything about LS swapping one of these cars! I appreciate any help or info thanks!

rocketraider

Just save the 455/400 for someone who wants to stay with Oldsmobile power.

With that said, and the fact all 68-76 Ninety Eights and many 88s came with 455s, what's the point of going LS?

Bfg

Go buy a Chevy and leave the Olds motors alone!

no1oldsfan

Plenty of LS haters. Just do your homework. Reliable horsepower with decent gas mileage. I have zero problems with LS swaps.

oldcutlass

I moved your thread to the Non-Olds powered section to hopefully get the advice you need. Good luck.

redoldsman

Maybe somebody on here will give you the advice you asked for instead of a bunch of crap like some people seem to have to do. It is not like you are swapping a 1970 W30 convertible. By the way, welcome to the site. There are lots of good folks here.

Koda

You'll want some high numbered rear gears and an overdrive transmission that can handle that torque. A big boat like a 98 will take a lot of power to get hauling, so all that LS torque has got to be held down while the wheels do their thing to fight the inertia of the heavier vehicle.

Motor mounts, trans crossmember, and a custom drive shaft. I'd change the gears in the rear and add limited slip. Upgrade the brakes, and maybe a little work on the suspension. I think motor mounts might be the hardest to figure out.

98olds73

Thank you all for replying! So here is the deal on why i want to go LS i have 2 455 engines with 2 TH400 transmissions. I had one of these 455's rebulit for big power i sunk almost 6,500 bucks into this 455 i had forged internals put in it as well as aluminum heads and intake. Also a big choppy cam it sounded sweet but shortly after the camshaft for some reason destroyed it self in the engine the metal shavings when through the whole engine and wreaked the crank as well. This was 2 years ago and my car has been sitting ever since with the engine pulled out. The other 455 i have is the original block to the car i tore it down because one of the main bearings went out and i lost oil pressure i should of just had that one rebuilt to stock spec if i could do it over again. So why i am considering the LS route is its a modern drive line once i get it swapped over if the engine blows up its cheaper/easier to replace than the hard to find 455 stuff. But it is tuff considering LS swapping my big 4 door boat because the aftermarket LS swap it does not exist for these cars they make LS kits for absolutely everything else GM but not big olds platforms unless its a late 70's model on. I have seen a guy do it to a 1970 olds 98 but that is different than the 71-73 platform like i said any advice or parts anyone has used would be great if anyone wants to comment or list parts on this post i would appreciate greatly thank you!

70cutty

Big block Olds failing sounds all too familiar.
6.0 is a great choice. 4l80e is your best choice for the transmissions. if you wanna wake up the engine, mild cam and matching springs would make a noticeable difference.
You don't need a kit, There is plenty of room in that engine bay, and there are plenty of universal fit parts. If we were able to squeeze a LS into a 72 Datsun 510, I'm sure you'll be able to install one in Olds 98.
For mounts take a look at Dirty Dingo universal sliders. ICT Billet is another place to shop at.

LS1tech is a good source of info.

olds 307 and 403

I personally am not an LS fan, they are lacking torque down low, talking multiple trucks I have drove a lot. I think the Gen 5 Direct Injection motors are much more impressive in the power and mileage department, harder to swap in. The LS are reliable but have their issues as well on certain years. As said, don't go less than a 6L, a 6.2L even better, if you can find one. The 4L80E is identical to a TH400 other than a lock up converter and .75 OD. Get a better gearing in the rear end to make use of the OD and make up for less down low torque. Expect a similar cost to your Olds 455rebuild, especially with trans and rear upgrade. I had a cam fail as well, it destroyed a $120 short block. A roller cam is going in my $5000 short block, not worth the risk. Good luck, look a other big GM car swaps for mounts, accessories and exhaust.

garys 68&72

Before buying an engine/trans you might want to think about your rear end ratio. Not sure what you have but with a 455 and TH400, it's probably in the 2s. I dont know what gears are available for that rear to swap out, but with a 6.0 or 6.2 with a 4L80/4L60 the OD gear would be useless. If you can find gears or a rear GM axle with around 3.42, you could use a 6.0 iron block, your current TH400.

98olds73

My car has a 2.73 rear gear with a TH400 transmission. I’m just trying to get it running and cruise it around at this point for a little bit.

OLDSter Ralph

What brand camshaft, lifters and valve spring pressure ? I'm guessing the 455 was not at fault, the camshaft manufacturer or the engine assembler were at fault.
Wouldn't it be easier just to buy something with an LS in and just blow up engines ?

98olds73

It was a comp cam with comp cam high energy Extreme lifters and what ever the valve spring pressure was on the edelbrock aluminum assembled heads which I forget what it was.

garys 68&72

Lots of cam failures over the last decade due to reformulation of oil with lower levels of zinc. I use diesel Rotella in my older motors, higher zinc content.