Just curious if anyone out there has tried getting power out of their 250? I will probably swap to 302, but this niche motor could be fun if I had pointers
I've been toying with the idea as an alternative to dropping in a 302. One way suggested to me is a two barrel intake which I know are still available. That, a header and better exhaust should make a noticeable difference. Still, both engine options will only perform just so better with the existing C4 transmission. A manual gives one more leeway.
I used the 69-70 pre-emission timing gear/chain to get better valve timing on my 250. This made a noticeable difference. Another trick was playing with the mechanical advance springs/tabs in the Duraspark distributor to get ignition timing to advance sooner. That made a big enough difference to write home about. Manual 5-speed lets you choose the right gear for the right rpm helps a little too. I also have a '80 1345cc fat log head shaved 0.090" and 6-2-1 header
As mentioned: ... money, time and resources?. my favorite machinist always tells me: "... your choice, it's just horsepower per your cubic dollar... " Although the 200 uses same integral intake cylinder head, the 250 basically is the stroked version of the 200 and the added rod length adds to the piston speed and reciprocating forces as well as increasing usable torque/powerband. The 'under-box' bore/stroke of the 7 mains contribute to a anvil strong bottom end. 250 stroke is .784 " longer than 200. (200/250 are not similar to big block Ford six 240/300) . Ford Small Block Six 250 CID inline . Stock block and cam with blueprinted matched 60 cc chamber head, HD V8 valve springs, ARP head bolts. Holley 2300 - 7448 2Bbl heavily modified for blow-through/ boost, Aeromotive 1:1 boost referenced regulator and FI electric pump and return at tank. Flame Thrower rev-limited HEI ignition - DS II distributor modified for vac and centrifugal boost advance limiting. Vortech V-2 centrifugal supercharger with pulley ratio spec’d for inline six 250' powerband. Centerforce weighted clutch, T5-Z 'Cobra' 5 Speed, 3.80 rear. AM radio and bench seat. With serpentine 6.125” (5.0 V8) Crank Pulley and 2.5” Supercharger pulley, the two pulley sizes and internal SC step-up gearing yields an IMPELLER rotation speed calculated at @ 22,000 RPM at cruise speed with engine RPM @ 2500RPM. At typical 250 SIX upper shift point of @ 5,000 RPM the Supercharger impeller speed approaches 45,000 RPM !. Calculating to an Impeller speed @ 750 Revolutions per SECOND. Vortech V2 specs are @ 680 HP at 20PSI boost at 50,000RPM Impeller speed.
