Thanks guys for the comments! We have found and bought full length headers and a old Edelbrock Streetmaster 390 intake that we will use with the stock carburator for now and portmatch with the heads we got.

We are stuck with camshaft options because we don't have any thrust plate to use with newer cams and we would be happy if someone would choose a camshaft kit for us from Summit Racing. We literally know nothing about suitable camshaft duration's and lifts and summit got loads of options. 
Heres the specs on the block and purpose again.

1961 300hp stock, 390 old type camshaft block without thrust plate. And we like to have a street powerband of 1500rpm to 5500 with around 400-450hp

Would this be a good choice using stock rockers and push rods?
https://www.summitracing.com/int/parts/cca-k33-224-3/overview/make/ford

Then i have found very little info about converting the cam retaining from old setup to new type thrust plate.
This was some good info i found http://www.mercurystuff.com/articles/352_skiddoo_hello_428.html
I know i got to drill and tap the holes for the plate but does something else need to be swapped? Like fuel pump and such?

Im a metal fabricator and was thinking if i would make a new thrust plate with a cnc laser cutter and polish the surface that faces the cam. I tried to search for new and used plates but they seem to be hard to find.

Thanks if someone would link us an straight forward "kit" that would fit us! 

Hello and Greetings from Finland.
Me and my dad bought a month ago a 1961 Mercury Monterey 4 door with the 300hp 4bbl FE 390 engine (Z code) that has not been run sence 1998 when it was in California just as a Father and Son project. (Its got factory AC  )

The engine is out and disassembled and went to a machine shop to bore the cylinders. They were pretty rough in the bores and water had pooled in them over the years. 0.040 over bore was not enough so we went with 0.060 overbore. Crank was great and the rest of the engine.
We now need to order pistons and a complete overhaul kit for the engine but we both are used to wrench Ford Y-Blocks in pretty much stock form so just to be sure we wont mismatch parts (high rpm/low rpm) and have to order parts again which is extremely expensive to Finland (25% tax + shipping!) we decided to ask politely from a Forum that has some experience on a setup.
The engine is going to be used for some highway cruising but mostly cruising, ripping some BMW's on the strips and getting some heads to turn on late evenings. It doesn't have to be a space shuttle but enough to put a grin to my face.
A little lumpy idle would be nice. 

Block is a 300hp 390 1961 without the web reinforcements that some trucks got at main bearings. Non Cross bolted mains. Hydraulic lifters.

Setup we were thinking about:
Flat top pistons to bump compression
Dont know what cam yet (suggestions?)
Edelbrock Performer RPM intake (stock is C1ae 9425b) (suggestions?)
Keeping the stock C1AE 6090-A heads with diy gasket matching, slight port job to remove casting imperfections and they should have 2.02" Intake and 1.55" Exhaust valves. 71.2-74.2cc combustion chamber.
Stock Autolite 4100 1.12 bore 590cfm or if we can find an used aftermarket carburetor for cheap. Because we will probably go Holley Sniper EFI in the future.
Drill oil pump output hole in block a little bigger and fix the crank bearing lubrication holes thats restrictive.
Stock Distributor with a petronix points delete and a High Voltage Coil for now
High volume oil pump + Reinforced pump shaft
Stock Rods (Dont know if you can get old rod bolts out and replace with ARP?)
Some grinding to help oil from pooling in heads and lifter valley
Double Roller Cam chain
Budget aftermarket oil pan with some baffle
I haven't found any aftermarket headers that will fit the chassis and there's little room for real headers so probably got to fabricate my own.
Diy 2.5 or 3" exhaust with X pipe
Removing stock mechanical Fan and replacing with Volvo 850 radiator fan. (to get more even coolant temps)
For now stock Ford Merc-o-matic Medium case 3 speed Dual Range + external oil cooler (C6 transmission may be bought at some point)
3.22:1 Stock Rear end

We were looking at SummitRacing for individual parts and then we found that Ebay has Enginetech Inc. 390 FE stage 1 rebuild kits like:
https://www.ebay.com/itm/Stage-1-Master-Rebuild-Overhaul-Kit-w-Flat-Top-Pistons-for-Ford-FE-390/163214175786?epid=26022915865&hash=item260052ae2a:g:3hAAAOSwoYxbfHRA
or from Summit but has dished pistons. without cam.
https://www.summitracing.com/int/parts/fem-mkp601f-600/overview/make/ford
But they seem way to cheap to be reliable? And does anyone know why these "Kits" have 1968-1973 years and some have like 1960-1973. Are all FE 390 kits pretty much same quality?

Feel free to point us in any direction and all help will be appreciated!