[Cliff R]

We had a higher end 455 on the dyno (well over 600hp) once with a ported Tomahawk intake on it. It was using CNC ported KRE heads and a "hefty" solid roller cam. So more of a "max-effort" engine but he still wanted it to fit under the stock hood and use the stock Q-jet carb and factory Ram Air components so no spacer.

The engine wasn't doing well on the dyno so we installed a Victor/Dominator to see if there was something going on with the intake and carb.

The next pull netted 102 more HP than the last pull with the Tomahawk and Q-jet......YIKES!

In the interim between pulls we fabricated a 1" spacer to blend the Q-jet to the Tomahawk intake. The spacer was very well done and nicely blended the flow from the carb to the plenum area. Put that intake back on and made within 10hp of HP of the Victor/Dominator!

An early lesson in this deal about how some combinations of parts don't work all that well.

Steve NEVER resists an opportunity to throw Dave Bishops test in my face since he was using a CNC pattern of my iron intake. I guess there is a crossover point between my iron intake working better than or not as good as an RPM.

It's the same chit as WAY back when Jim Hand went to Ark City with a big Holley carb and ran some of the best times his Wagon ever saw. Folks threw that in my face for years, even after Jim went back to the stock intake, Q-jet, and ran better numbers and didn't have the "mine-shaft" air and perfect track conditions they had at Ark City for that race. It just goes with the territory and after doing this now for over 40 years I'm used to it and understand the propaganda associated with aftermarket "high performance" parts. When I outrun them on the dyno or at the track there will not be much mention of it. Get outran by one of those parts and you'll here about it hundreds of times for years to come!....LOL

Anyhow, at the 500hp mark on a very well prepared 428 build the RPM brought nothing to the table, so at some point the RPM may be better than a stock intake, but it's unlikely it does anything for 90 percent of the Pontiac street engines it ends up on, and probably quite a bit less after the drop base air cleaners and other "cobbling" required to install it.

I ran an RPM for about 6 years on my last 455, had to ditch the factory Shaker top and get a shorter one only to find out that it HATED the factory air cleaner lid being moved 1" closer to the carb. I briefly tried the K & N Xtreme lid but it hated that too, so I had to fabricate a custom air filter and shoved it in the Shaker opening. It was all good after the cobbling and I ran over 120,mph at Norwalk on the first outing. Before I could bust into the 10's with it they shut me down and we had to retard the timing 4 degrees, put two cylinder heads in the trunk and short shift at 5000rpm's to keep the track officials happy.

A few years later I decided to return the car to street duty and put the iron intake back in place with the stock Shaker and factory air cleaner assembly. I also put an electric choke back on the carb, and full length mandrel bent tail pipes. I figured it would slow the car down some but was way under the roll bar rule anyhow and not planning on installing one.

To my surprise the car went quicker in ET on the first outing to our local 1/8th mile track at about the same MPH! So much for slowing it down. I typically ran bottom 7's around 95-97mph with the RPM. Most runs would be in the 7.20-7.35 range depending on DA and track conditions. I managed a 7.18 with the stock intake and Shaker parts in pretty hot/humid weather!...... FWIW.......Cliff