Best way to proceed with improving up 427 Windsor street setup

[SPF1061]

Originally Posted by Ace23

So while the WWF cage match of the 427 Windsor vs 427 FE is brewing I would like to better understand the following so I can understand the decisions I am making.

ALL QUESTIONS ARE BASED OFF A WINDSOR PLATFORM BETWEEN 427-460CI

*Edelbrock list the Performer RRM Air Gap for a RPM range of 1,500-6,500. Now with this being said I am sure that cam selection , cylinder heads and compression all play a major role. My question relates to a street car that lets say peaks at 5500-5800rpm leaving you shifting at 6000rpm. Why is the dual plane not the appropriate intake? Brent why did you build your 438W with the RPM air gap instead of the Victor Jr?

*2" primary header size. This has been a 50/50 answer that I've recieved. Why on a street car would you keep 2" headers? The only information I have come across that seems to have come from someone who actually had 2" headers was an old post on here were a guy had a Roush 427 and he stated that on the dyno the 2" made a few HP more but only on the very top end......while the bottom end was down 25-50 torque. Is the 2" header design only applicable for cars that would be tracked?. If a street car is setup for 6000rpm why would a 2" primary header size be appropriate.

I put 2" headers on my Roush 427R. (Dual plane intake with AED 750, 3" Stainless Specialties mufflers). They sounded and felt really good at the very top end for the last 1500 rpm or so, just before it hit the rev limiter@ 6400 rpm. Low end torque was way off. This was verified on the dyno, on the drag strip and daily street driving seat of the pants. Overall performance was better with the stock Superformance headers. I really wanted the bigger headers to be better. In my experience, they weren't. FWIW. Your mileage may vary, so to speak.