What kind of performance difference would I see between the Edelbrock Performance RPM and the Merlin/Dart with the brass water jackets?

http://www.worldcastings.com/prods_pages/063030.htm
If you click on key features it tell about the brass water jackets.

http://www.edelbrock.com/automotive/man_bbchev.html

Depends on the engines and what rpm you plan to spin them too. I run 470cid with mild hp and wanted to spin to 5400rpm. So last winter I switched from edelbrock rpms to dart single planes. Lost a good 2 mile an hour. I am going to sell the darts this winter (rpms too) and buy edelbrock air gaps. At least that is my plan right now. The air gap feature of the darts dropped my oil temps so that is why I am not going back to the rpms. If I had 502s I think the darts win.

BT

420 HP with with 500HP cam spinning 5000 RPM.

They're two completely different types of manifolds. Not even a realistic comparison. At the rpms you'll be turning, the RPM will be a much better manifold. The single plane Dart will feel like a pig by comparison.

A good single plane will start to outperform a good dual plane from about 5400rpm on up.

Arn't they both single planes?

NO, a RPM Airgap is a dual plane intake and a Dart is a single plane intake.

John S.

The Merlin is not a "Dart" intake. Darts are made by Dart and Merlins are made by World products. The Dart is what came originally on your 420.

The Merlin is a single plane. It is completely open where the carb bolts to it.
The Edlebrock RPM is a dual plane. It has a divider where the carb bolts to it.

Get an Edlebrock Airgap and be done with it. It will most likely make the most power at all rpms that you will run. If you are worried about salt, check into getting the water passages hard coat anodized. Edelbrock also offers some exterior coating options to protect it and keep it shiny.


http://store.summitracing.com/partde...5&autoview=sku

Nope..

The Edelbrock Performer RPM air gap is the right choice for your combination. It has a rpm range of 1500-6500. It builds a nice broad flat torque curve a coupled with the HP 500 camshaft should work very well. I would advance the camshaft 3-4 degrees when you assemble the engine. This will also help build more power in your rpm range.

Is this a good intake for a 540ci??
9:1 comp, Canfield Aluminum heads, custom cam 112 ls 610 lift 234/240 dur.
850 Daemon carb worked by Nickerson

Currently running a Hurricane from competition productions, however, I have been told that is not the best intake for my setup.