Parts compatibility Gen1 and Gen II 3SGTE

Hey guys. 1988 ST165.
So I'd consider myself pretty competent when researching aftermarket parts but factory parts are killing me.
I've been searching for the better part of a week and still can't find what I am looking for.

Does anyone have an updated commonly used source for factory / OE parts?

I'm looking at PrimeDriven, KO Racing, and Kbox, even twosrus for maintenance parts. GenII stuff is everywhere. I've got a different p/n for the thermostat GenI vs. GenII 3SGTE. 90916-03090 (dealer sourced) vs 90916-03075 (Prime) so I am a little hesitant to order parts and hope that they work.

I'm happy to pull the trigger, as long as I know that these parts are cross compatible: GenI 3SGTE vs GenII 3SGTE. Can anyone verify? Or point me to a compatibility / interchangeability resource? Where are people getting their parts from? Swapping a GenII in and calling it a day? The valve cover gasket is NLA from the dealer and I'm not ready to trust what I am finding on rockauto yet.

Valve Cover Gasket
Distributor Cap
Distributor Rotor
Distributor O Ring
Cam Seals
Valve Cover Bolts
Oxygen Sensor

It's been a real headache and I am way past ready to drive.
Thanks for any help. In all the Toyotas I've owned, this one is throwing me the most curveballs when it comes to parts. I'm not used to parts being this cryptic/ rare / difficult to find but also maybe I am just thinking to hard about it.

With the exception of the valve cover gasket and the distributor cap, all the other parts come up in parts.conicellitoyotaofconshohocken.com

Also, I stopped working on my ST185 for close to a year, now that I'm seeking parts for it, I found out that some parts are starting to get discontinued by Toyota for the gen2.

Why not trust RockAuto? They offer Beck/Arnley and Denso parts for the majority of what you've listed, which are OEM just not in the red & white Toyota box. As an alternative, you can try giving your local Advance Auto Parts a call with Toyota's part numbers and ask them if they can get what you want through WorldPac. Which again, are OEM parts without the Toyota box.

All-TracDreams":3koyyu35 said:

Why not trust RockAuto? They offer Beck/Arnley and Denso parts for the majority of what you've listed, which are OEM just not in the red & white Toyota box. As an alternative, you can try giving your local Advance Auto Parts a call with Toyota's part numbers and ask them if they can get what you want through WorldPac. Which again, are OEM parts without the Toyota box.

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Yep, I bought an AC compressor from RA and it was actually a Toyota part. . Literally, it had a Toyota sticker on it but in a generic box. I can vouch for BA parts as well from working at Advance five years.

Thanks so much for the leads guys. I will go with those two.

And thanks so much for that info as well r-town!