Offenhauser 4bbl Dual Plane 2.8L V6 13.92 at 101MPH
I had a 1976 Mercury (Ford of Europe) Capri II Le Cat Black S with the Offenhauser Dual Plane 4BBL manifold, a 390CFM Holley 4bbl, Norris ground European Ford Cam Blank (my dad was a Ford VP and could get things not available to the public), Aluminum degreeableTiming gears, Ported heads (by me, they crack so keep some handy), and aluma-coated headers.
This car was fast, 13.92 at 101 MPH was the best pass I ever made at Carlsbad Raceway.
The German 4 speed was great for road racing, but weak at the drags...I kept a spare 4 speed in the garage thanks to Pick-A-Part $35. price .
This engine made awesome power from about 2800 RPM to 7200 RPM where I would shift before it fell off or would float the valves.
As for the Offenhauser manifold, its unique in design because the 2.8 Liter engine is a 60 degree V6. The "square flange" Holley 4 bbl is literally wider than the intake manifold.
Offenhauser designed a GOOD manifold which offered high velocity dual plane ports within the small available space between the heads.
This design required the manifold to be a two piece design where the lower section IS BOLTED TO THE HEADS WITH BOLTS INSIDE THE MANIFOLD! Yes inside the manifold. Always use LOCTITE on these bolts. The upper half of the manifold then covers these bolts and has enough height to allow the 4bbl linkage to clear the valve covers. Weird, but it works very well.
This engine is easily able to produce 200 HP and is about the size of a beer keg.
The closest performance match I have found was the power of my 5 speed SHO Yamaha powered Taurus.
Hope you enjoy your Offy motor and smoke some V8's along the way.