Welcome to the VMF.
Looks like a factory 90’s block with aftermarket heads.

 

The F1 means the block was designed/engineered for the 1991 model year. The 0H11 means the block was cast on August 11, 2000. The Explorer/Mountaineer was the only vehicle still using the 302/5.0 engine in 2000.

 

Thanks!
Unfortunately, not much is known about his past, so any help comes in handy.
With some custom modifications, the current engine specifications are as follows:
-302 cui
-Edelbrock 1406
(101 front, 98 rear jets, 1449 bars, pink springs)
-RPM Gap intake
-SVO Gt40 x302 heads
-Crane Cams 1.7
I don't know what the camshaft is at the moment, I would guess e303 or something like that.
-Flat pistons
-Long tube headers
I want to increase my output to 380-400 hp max. (on cranckshaft)
What changes do you think I would need?
I was thinking of charging this engine with a weiand 174 roots blower and a 750cfm carb..

 

Getting 380-400 hp out of a 302 with factory iron heads will require a lot of work. Perhaps a lot of porting and the blower as you suggested will get you there.

 

welcome

 

I think the GT40-X302 is a bare aluminum head version of the GT40-X303 head assembly.
Specs: https://performanceparts.ford.com/download/instructionsheets/FordInstShtM-6049-X303X305Y303.pdf

It's too bad that I just threw out some old Summit Racing catalogs that probably had these crate engines listed.
If I recall correctly Ford's SVO 5.0 crate engines with the GT40-X303 heads and B-303 cam made 330 HP. And the crate engines with the with the GT40-Y303 heads and E-303 cam made 290 HP.

 

* Sorry, I wrote wrong, I checked again, y302 heads.

One of my tips was the Gt40 crate engine, as I couldn’t find any unique IDs, just a 5-digit sequence of numbers under the ignition distributor.

Ford Crate Motors

Or what else was noticed in the froozen plugs is "Precision MFG 11/2 USA".
In principle, the Mustang went to Germany in 2013 from California.

 

F1SE BB is a 91(year designed) Thunderbird 5.0 engine block. I run the same block in my 331. From back when I was inspecting mine it appears it was made with a little bit more meat in it around the cylinders than the typical E7 block you might find on a mustang. I don't think it particularly makes it that much stronger though.