Does anyone have any good info on these housings? They would be used for a naturally aspirated 20B engine aiming for 450HP at 9,000. I heard the timing was a little conservative...any thoughts?

Good housings? Bad? Why?

 

I'm not sure why people say the timing is conservative on them. Most people like p ports that have too much timing with ports what are too large. Speedsource racing did extensive dyno comparisons between the factory Mazda p port housings and the RB housings. What they found was that the Mazda housings made just slightly more peak horsepower but the RB housings made more average horsepower over a wider powerband. Average wins races. They run the RB housings. Just food for thought.