RPM range question for Holley Hi Ram......

[427dart]

They state the range from 1500-7000 RPM and the runners look to be close to same length as the Edelbrock 426 Hemi intake which works well in the 2500-6500 RPM range. I did see an LS dyno test on a smaller cube engine where power gains were from 5500 up over the mid length ram Holley intake.
Is this due to large plenum of the Hi Ram as compared to the Edelbrock Hemi intake?

426 Hemi intake



holley hi ram 351W

[jeff swisher]

I take advertised RPM range as just that.. advertised.

What is the RPM range on a stock iron Q jet intake how about a Buick 2V intake.
I have had heads and cams that took both of those to a screaming 7800rpm lickity split.

The runners on the lower intake in the picture look very short for the middle runners and a smooth floor leads me to think they made that for Port injection.. why else would you build a short intake like that with a flat smooth floor.

For my street stuff the taller I got my intake and carbs on the tunnel-ram the better it ran everywhere.
I was never down on RPM on any intake based on what their RPM rated specs were.. i think that is just advertising.. trying to sell intakes to the masses and guessing where in the RPM range the masses will spend time.

Lot more to the rpm potential of an intake based on intake alone.. you must consider valve events and heads.

[F-BIRD'88]

Why not ask Holley tech how long the runners are and the CSA of the runners of that intake
you want to know about. Phone e-mail...... Tell them you are building such a engine and want to know if it fits your plan. DO NOT ask about rpm range. Ask about the ports.

[F-BIRD'88]

With the right carburetors and custom plenum top it will have a very broad good operating range. Yes it will easily extend up high.

[F-BIRD'88]

Then....if you can/will think outside the box a bit you can adjust the dimensions and port length (if needed) to fit your street combo better. All while having your as cast manufactured appearance you wanted.
This intake is a good "base" start point for that.
And you are good at fabrication.