I know that of the requests, two are quite serious. One is spec engine for auto-x and the other is a power nut (meant in a good way), that has had a myriad of cars.
If you want to be conservative and compare to stock EJ204 (NA davcs heads), we can assume 93 Nm of torque on the engine and carry out basic BMEP calculations and lift MPS to 25 m/s (race engine limits), you’ll be in the ballpark of 260 bhp as a 2.0L. If I choose the same low torque value but bump to 2.43L you have 226 Nm (167 lb-ft) and 317 bhp (237 kW).
If you choose to bump the nominal torque value to something more like that of a race engine (120-140 Nm/L) things change drastically but note that this IS running to a max Mean Piston Speed of 25 m/s and would require a fully engineered and developed package to get these kinds of efficiencis…so I’ll use 120 Nm/L to play it more realistic, after all, the EJ ports suck and we have less than ideal layout conditions for manifold design.
You’re looking at a max engine speed of 10,000 RPM with 305 kW (409 bhp) and 292 Nm (215 lb/ft)....so unless you REALLY want to spend the coin of building an NA engine for this power, go with a VF39 and EJ205
...coming from an engine builder
Although I still think a conservative 9k RPM redline on a 2.34 destroked engine and a low boost (1 atm) .63 AR turbine 60 lb/min'ish turbo (50mm EWG) would be a blast. Net about a 400whp with a broad tq curve and keep great transient response. Of course you could dial it back or turn the wick up depending on your pucker factor