The '84 was rated at 175 HP from the factory, but mine (bone stock!) puts almost that much to the rear wheels (about 170 RWHP). A good aftermarket cam and headers/exhaust will easily add 40 to 60 HP with the intake and carb he already has, even with the stock heads. The 271/289 might bump the compression a bit too much, but the 351's should be OK with 93 octane pump gas. With those heads the other changes he could reasonably expect a 100+ HP gain, and that might be a bit much for the stock tranny, as well as putting a bit of a strain on the engine internals.
I have a friend who has an '85 Mustang Convertible. The car has a 302 with
> an automatic. He recently replaced the throttle body injection with an
> Edelbrock intake and a 600 Holley. He owns a number of Mustangs and says
> that this '84 is an absolute pig in the H.P. department. I am trying to help
> him out a little and have some questions:
> 1) Anyone know anything about the camshaft Ford put in these engines? This
> one is not the roller version.
> 2) Does anyone know the chamber volume in the cylinder heads? I have an
> extra pair of 271 H.P. 289 heads, and a set of '69 351W heads, but am
> concerned that the they will bump compression ratio too high.
> 3) The trans is an automatic overdrive. Are they strong enough for a little
> more power?
> He had one of the local guys do the injection to carb swap. They used a Ford
> distributor with an MSD 6A.
> Thanks
> Bill
>
>