Olds 350 to Chevy 350 Swap

zipties

Apprentice
Feb 2, 2022
52
18
Hey, I'm sure this has been done a million times but I didn't see any recent threads and don't like reviving old posts so here's a new one.

I got my hands on an SBC for my 78 Cutlass after pulling the Olds 350. I removed most everything from the engine bay to prep it. I have a general idea of what needs to be changed/modified for this swap, but help never hurts.

20220806_161329.jpg


I'm going to retain the BOP trans for now and have an adapter plate. My question is which flexplate I need to use, the Olds or the Chevy? I got the JEGS adapter, but I see discussions about needing spacers or even making clearance in the bellhousing. What's necessary for that?

20220806_160537.jpg


I redid my wiring harness and it's in good shape. Guessing I need to extend my starter wires since they're on opposite sides, are there any other wires that need modified or added?

Part numbers for whatever I'm forgetting would be a big help - I need motor mounts for sure. I already have everything ready for the SBC (i have buckets of SBC junk which is part of the reason for the swap) so not worried about that. Just want to make sure I have all the swap stuff covered.

Thanks in advance. FWIW the Olds motor still hasn't been claimed if anybody is in need of one, hit me up.
 

565bbchevy

Geezer
Aug 8, 2011
9,125
113
Michigan
My question is which flexplate I need to use, the Olds or the Chevy? I got the JEGS adapter, but I see discussions about needing spacers or even making clearance in the bellhousing. What's necessary for that?
You would use the flexplqte for the SBC, for the trans adapter you need to space out the torque convertor the same amount as the thickness of the adapter but you can use grade 8 washers with the correct ID and thickness.
 
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zipties

Apprentice
Thread starter
Feb 2, 2022
52
18
You would use the flexplqte for the SBC, for the trans adapter you need to space out the torque convertor the same amount as the thickness of the adapter but you can use grade 8 washers with the correct ID and thickness.
Got it, makes sense. the BOP trans is still in decent shape.

got the old olds removed:

20220810_220901.jpg


i love working a cherry picker on gravel... but the hard part is done.

i'm going to take this chance to clean up and refurbish the engine bay. that includes removing the nonfunctional HVAC and giving everything a good spray with the pressure washer. I'd also like to upgrade the steering shaft and make the wiring modifications while the bay is open.

a guy was supposed to come and buy the motor today but flaked, but it's all good.

Speaking of buying motors, here's the new one:

20220810_221338.jpg


it's just a basic 80s SBC with around 80k on it, and it's actually in decent shape. I got the whole thing, including the stainless long tubes in the back, for less than 200 bucks. all I need is a belt drive which I'll probably piece together from some other blocks, and a new flexplate.

Really hoping to get this done this month. are there any holes I need to drill for the motor mounts?
 

565bbchevy

Geezer
Aug 8, 2011
9,125
113
Michigan
are there any holes I need to drill for the motor mounts?
The holes are already there you just need the proper frame mounts and SBC clamshell engine mounts.
They mount like this using only 3 bolts per side and overhang slightly.
1660258844530.png

These are the frame mounts I used in my Regal
 
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565bbchevy

Geezer
Aug 8, 2011
9,125
113
Michigan
i'm going to take this chance to clean up and refurbish the engine bay. that includes removing the nonfunctional HVAC
I would reconsider removing this, instead I would keep the heating aspect functional and install a new heater core but not modify the case.
If sometime later on you want AC it is really not that hard to get it working again when the case is still there.
The AC in my Regal didn't work when I got it but it does now and works well.
20220714_211743.jpg
 

bracketchev1221

Royal Smart Person
Jan 18, 2018
1,190
113
The flexplate is the big issue for install. Make sure you get one for the year of the engine if you don't already have one. Yours looks to be a 1 piece rear seal engine and I believe they were externally balanced on the back end. Don't remember the newer engine cutoff for this as I have been out of engine building business for several years. When I worked at the engine shop 1 piece engines were just starting to catch on.
 

zipties

Apprentice
Thread starter
Feb 2, 2022
52
18
I would reconsider removing this, instead I would keep the heating aspect functional and install a new heater core but not modify the case.
If sometime later on you want AC it is really not that hard to get it working again when the case is still there.
The AC in my Regal didn't work when I got it but it does now and works well.
I typically don't run A/C in my cars. Heat is an exception but I now live in an area where it doesn't get as cold in the winter months, and I don't plan to drive this thing in the winter much anyway due to salt.

the assembly is actually in great shape and i'd rather pass it along to someone who can put it to use in their G.
 

zipties

Apprentice
Thread starter
Feb 2, 2022
52
18
The flexplate is the big issue for install. Make sure you get one for the year of the engine if you don't already have one. Yours looks to be a 1 piece rear seal engine and I believe they were externally balanced on the back end. Don't remember the newer engine cutoff for this as I have been out of engine building business for several years. When I worked at the engine shop 1 piece engines were just starting to catch on.
the block is from 86.

i'll do some research to see what I need to look for in junkyards, or maybe I'll cave and buy a new one if they make them to spec.
 

565bbchevy

Geezer
Aug 8, 2011
9,125
113
Michigan
A one piece block will have an aluminum adapter on the back of the block for the crankshaft, did you not get a flexplate with the engine?

1660313798653.png
 
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zipties

Apprentice
Thread starter
Feb 2, 2022
52
18
A one piece block will have an aluminum adapter on the back of the block for the crankshaft, did you not get a flexplate with the engine?
hard to tell with all the gunk but it's there:

Screenshot_20220812-102321_Gallery.jpg


I got everything but a flexplate and a belt drive.
 

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