Porting and Polishing

[dn010]

My heads have been done as well but I am using B280F with heads that were very restrictive in the exhaust ports. On those heads there is a large chunk of aluminum partially blocking the port which can be safely ground away. One day I'll dyno my B280F/efi setup just for kicks.

[delornut]

Does anyone by any chance know what the measurable difference is between stock and port and polished heads with aggressive cams? Are we talking 3 hp? 5 hp? 10 hp........ 0.5 hp?!

Before I go spending the money i like to know its worth it, but i want this to be the first and last time the heads ever come off 3205 so i figure do it once and do it right or don't do it at all.

Velocity is a major part of head design. Porting should stop short of upsetting air flow velocity. Without a flow bench and the experience to back it up you could do more harm than good. One of the last years I worked for Ford I went to a two day class with a NASCAR engine builder and a major drag racing engine builder. We bench flowed a 351 Cleveland head and it was quite obvious when things had gone too far and velocity started to drop off.

Bruce