[Creative cut designs]

Receiver for my av3's is my older sony str-da50es would that be sufficient?

[hawkeyejw]

The A/V-3s are 91db sensitivity and rated between 6-8 ohms so your receiver will be able to play them just fine. Is there going to be room for improvement? Sure, but I would recommend you don’t worry too much about perfecting the signal path immediately. Once you finish them, plug ‘em in and enjoy them. Then start figuring out how to optimize your room and components to get the most out of them.

[Creative cut designs]

I actually temporarily hooked them up to make sure everything works before I close them and paint them

[charmerci]

I found a generic Sony in a thrift shop for a few bucks. It doesn't have all the qualities of my more expensive equipment but it sounds pretty good!

Yeah, your receiver is fine.

[Creative cut designs]

Back to n the day the es model was sony's high end models

[S Clark]

Just for grins you might look at a TDA 7295 amp.  For the cost of a Big Mac, the sound is actually really good.  Really good.
It kinda goofy, but a $4 Chinese chip amp actually sounds better than most of the big name receivers from the 70's and 80's.
There's been a ton of stuff written about them here at AC. 

https://www.ebay.com/itm/12V-TDA7297-2x15W-Car-Digital-Audio-Amplifier-Dual-Channel-Module-Board-Kit-DIY/274249248271?hash=item3fda876e0f:g:2KIAAOSwjP9eOS90

[Creative cut designs]

I really don't know anything about stuff like that or how to hook it up

[S Clark]

I really don't know anything about stuff like that or how to hook it up

No problem.  Old receivers are easy, cheapish, pretty decent sounding, and at every thrift store.