I have a 65 Mustang with the 289 A/4bbl rebult Autolite motor. I know the rated HP in 1965 was 225 HP. Here are my questions

What is the real SAE HP of a 289 A code?

I am changing out the stock manifold to the HI PO Manifold and adding the Magnaflow exhaust with the pertronix ignition.

Does anyone have a gestimation of the HP gains at the rear wheel. I know if I use the 225 HP numbers I can expect 15% to 30% increase with the Manifold/New Exhaust however I do not think that the car will have anywhere near 290 HP or 275 HP at the rear wheels?

Any help would be appreciated.

 

Netrating of a factory A-code is probably closer to 180hp at the flywheel. With the manifoldsand exhaust and assuming the engine is in good tune, I might guesstimate a 10-15hp gain.

 

I know thatthe 289 coupewe havewith a full motor rebuild several years ago to a mild performance level with performer intake, cam, stock heads with intake/exhaustport work on them,hipo code manifolds, 2 1/4 inch dual system with h pipe, 4 speed toploader and an 8 inch rear makes 180 at the back tire.

 

thanks for the info,