Unfortunately about the only thing I can say about the RPI headers is that they fit....
I know the chap that originally commissioned them...
I've fitted a set, tested them, and then removed them, threw them away and fitted a Librands manifold....
Instant and measurable performance increase...
Simon @ SiFab.co.uk
Interesting. Did You test them by the seat of your pants, or a rolling road? I used a rolling road to test the complete engine but did not have comparative information on other headers. The results were not spectacular. I have since replaced My 3.5 engine with Buick 215 heads with a Morgan 3.9. (sourced from Bill Fink) Very much improved.
I'm afraid my pants are nowhere near accurate enough....
Everything I make gets thoroughly tested, before it gets released to the public. In the case of engine performance modifications , that means either on an engine or rolling road dynamometer, with back to back testing and any tuning necessary to gain maximum benefit.
I wouldn't want cars failing any emissions tests if fitted with my upgraded parts for example.
A lot of the time I'll carry out a lot of hand calculations and virtual load testing on components in the design process.
The rear axle/driveshaft/wheel bearing conversion I designed for the Peking-Paris +4 would be a good example of this.
Simon @ SiFab.co.uk
