A few thoughts....
Lippy's engine does not have
oil restrictors. I don't restrict
oil to the lifters on a street engine. He also has about $1200 worth of Isky EZ Roll Red Zone bushed lifters, so we didn't want to give those up to change to a hydraulic roller.
Jay's book is a nice chunk of information, but a manifold comparison on one engine will by no means give data for every combination out there. I do believe he did a lot of his testing on a 428 (??). Jeff's engine is about 60 inches bigger.
Now, speaking generally, a larger engine will make short work of a larger intake. A Victor intake on a 390 would exhibit a lot of the "bad manners" that people think about with single plane intakes. However, a Victor intake on a 487 wouldn't be that big of a deal whatsoever.
The catch is that Jeff's heads flow almost 350 cfm and have very tall/wide ports to accomplish that. His intake has been fully port matched and worked in the plenum. The difference between it and an out-of-the-box Victor is *substantial*.
With that being said, this engine was originally designed to be a higher strung engine. Pulling it down to a much lower power band would probably be highly complimented by a Performer RPM (especially with a 1" tapered spacer - we've seen up to 30 hp bump with those on the dyno).
However, there are a couple things that would complicate that swap. For one, the Victor is already milled and cut to fit the heads. It's very possible to put a Performer RPM on and the ports not line up, which would necessitate milling the flanges and/or the valve cover rails. The fact that it's not ported or port matched probably wouldn't make much difference here. Velocity is king and you want high velocity at low rpms on the street.
All-in-all, my gut tells me the Performer RPM would be a better match, but if he were to put the Victor back on, he would probably just notice some throttle response lag.
Everyone tends to forget that these cars are 2500 lb street-legal race cars. You make compromises. If you lose 10-20 hp, it's not going to be noticeable. If you lose 10-20 lb-ft, it's not going to be noticeable. What is noticeable is having the power available and available immediately in the rpm ranges that you spend most of your time driving in.
If I remember correctly, Lippy's car is also geared lower in the rearend (3.70-3.73, am I right?) and is running a TKO 600 which could potentially alleviate any throttle response issues. It's not like it's a 3.31 rear with a close ratio Toploader...
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