65 Barracuda daily driver

I started taking off the intake manifold etc. Man, everything was on there with sooo much RTV... But the inside looks really clean to me.

tvPjnpmxRoHqe8QK3w4_3Lx5Mw-6VkHOZ_3l43EzxXqRHchvPhdBfwQ51cxvI3yNw8bGRLQ=w798-h1064-no?authuser=0.jpg

So the block is '69 and to my surprise the heads are #4027163 heads, which I found out makes them from 1977-86. Can anyone tell me, if those are better are worse compression wise compared to the stock 1969 heads? The seller told me the engine was completely stock except the Edelbrock Performer intake, which I took off, because: I'm realizing how expensive everything is getting. A new 4BBL carb is gonna cost another 400 bucks or so. And I found a '75 2BBL intake including Carter BBD carb. I know how to dial in a BBD and so I'm gonna clean this up and bolt it on for now. The car is still my only daily driver, so it's crucial that as soon the slant 6 is out of the car, that I can get the 318 in there and running in a short amount of time. I plan on re-using the relatively new slant 6 Champion aluminum radiator, the alternator and starter. I want to spend the extra money on the exhaust. Currently I'm thinking single 3" exhaust. Waldron makes a 2.5" exhaust for $478 ($618 with shipping), but I want to go to the muffler shop down the street who built the 2 1/4" exhaust for the super six slant that's still in there. I think I paid a little over 300 bucks for that.

FEYZy9kKFjQ_ynID-mQ8tyDUqTz7Qy_sfgKxVTsd-thEtZmfMQTx9IloPW2ndnouZJlW8g=w1419-h1064-no?authuser=0.jpg

Can anyone tell me what that metal plate is for and if I can remove it? Also, how to remove it? I assume these plugs are plastic and it will come off easily, but I wanted to check first. I mostly want to clean up the deposits from under there, but at least in the shape it's in, it probably won't do much anyways.

2ezbQaLjR1beguQgYxuG8ruvOPO1uUNnFpjg7OH06sfXJJQpLUCC0BXfSRWalQCgFcU267A=w798-h1064-no?authuser=0.jpg

For now I sprayed it with some Easy Off oven spray to take the paint off, so I can paint it red, because that's obviously the most important thing right now, haha.