SBM Port Molds

I believe, as both of you do, that it is about air flow. This is a street head that was meant to be an improvement over the Edelbrock style head, so TF needed more air flow for advertising purposes. If it were a factory head, emissions would matter. If it were a race head, hp would matter.

I have to think NBT is correct that this is somewhat of a less than perfect approach to fixing a problem, but I am not suggesting that I know a better way. It seems TF has done a really good job with an OOTB head. The low port and 18 degree valve angle of the SBM present their own challenges. This may be the best, low cost solution.

I have read several places that the intake stroke of the piston gives you X amount of energy to work with to get air into the cylinder. The more energy that is wasted on turning and redirecting air, or the more energy wasted on swirl, is energy that is lost. In other words, loss of port efficiency.

However, if the band-aid produces a higher performing, low cost head then it was a good band-aid. Until a better one comes along.