I've got some 289 blocks, cranks, cylinder heads, etc. in here in case anyone would be interested in a period correct 289 build.
These would start at around 300 hp with a factory cylinder head, hydraulic roller, etc., and would go up from there. We have made 450 hp with the 289's, using ported C5 heads, and a .500" solid flat tappet camshaft.
This is David Cobb's 289, based off of the factory crankshaft, a little longer rod with shorter piston combination, and World Products cast iron heads. Blue Thunder Shelby style intake, with a custom hydraulic roller camshaft.
That little engine made 310 hp @ 5800 rpm with 315 lb-ft of torque.
That one is a little more higher end build, built for a FIA rules Cobra in the UK. The rules dictate we have to use a .500" lift solid flat tappet camshaft, factory cylinder heads, either a factory style dual plane intake or Webers, etc. This one, with ported C5 heads, cranked out almost 450 hp.
We have seen a spike in customers wanting "period correct" engines for their Cobra builds....been doing a lot of 289's and 427's lately. The good thing is that we can introduce modern components into 60's platforms: modern ring packs, roller camshafts, modern carburetors and induction, etc.