Pontiac swapped Cutlass?

Djdavila1

Not-quite-so-new-guy
Oct 24, 2017
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#1
Hi everyone i have a 82 cutlass supreme with a olds 403, and im going to look at a Pontiac motor but we dont know for sure what size it is until i look at it but the owner thinks it may be a 400 or 455 has anyone done this before and or know if it will bolt right up?
 

307 Regal

Royal Smart Person
Oct 21, 2009
1,512
274
83
Northern Indiana
#2
I know very little about Pontiac engines, but you'll need to change a few things including but not limited to engine mounts and exhaust. Depending on where the starter is, you may have to move the battery from one side to the other. I had to do that when switch to a Buick 350 from an Olds 307. If I remember correctly, early G bodies could have a Pontiac 301, so the parts are out there to support the swap. At least to some degree.
 

Local Hero

Greasemonkey
Nov 24, 2016
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305
63
52
Northcoast, Cleveland, Ohio
#3
I went the other way. I put an Olds engine in a Pontiac. Both were 350 c.i.

Correct, the exhaust is different. The fuel pump is on the other side. Pontiac is on the driver's side and Olds is on passenger side. You need different mounts. I would also get all the accessories for the engine you're installing such as power steering pump, alternator, and AC compressor if necessary.

The items themselves are interchangeable. But you'll want the brackets that match the engine.

Last, the trans will bolt up. Buick, Olds, and Pontiac all used the same transmission bell housing. The starters are different but they're on the same side, driver's side.
 

olds307 and 403

Comic Book Super Hero
Oct 14, 2008
3,231
658
113
Melville,Saskatchewan
#4
Why are you dumping the 403? Just get early 330 or 350 heads and upgrade the cam, both will help a lot. I considered a Buick 455 before I found my 403. Nothing interchanges except the distributor cap and maybe the carb but the calibration will be different. Mounts, exhaust attachment and all accessories are unique to each make.
 
Nov 12, 2017
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#5
Motor mounts from a gbody with the Pontiac 301 will have the right mounts. I pulled a 301 from my grand Prix to put a 400 Pontiac and just used the mounts from the 301. If it's a 400 or 455 it will be stamped on the side of the block towards the front.
 

Qdub24

Royal Smart Person
Sep 6, 2006
1,755
368
83
Columbus, GA
#6
My first car was an '83 Cutlass w/a Poncho 400 built by my Pops.
 

MrSony

Comic Book Super Hero
Nov 15, 2014
3,681
1,199
113
Des Moines, Iowa
#7
No real reason to go pontiac from olds. It's a pita mostly. Mounts (301 g body mounts, especially the frame pads) are hard to find. I think you can use F body (firebird) mounts, but I'm not sure. With an Olds 403 you can swap in a solid main 350, a 455, or beef up that 403 as olds307 and 403 said. It's more trouble than it's worth in all fairness.
Also, if it has this little doodle on the back of the block on the passenger side, it is either a 326, 350, 421, 428, or a 455. 389s and 400s do not have this lug. Only way to tell from there is measure the bore or casting numbers.
 

Attachments

Nov 12, 2017
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#8
After 1970? All Pontiacs got cast with the cubic inch stamped on the side of the block. The 301 has the dipstick on the drivers side.
 

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