Whoops! That 50 gallon drum thing was from my post in the Exhaust forum. Guess a couple wires got crossed in my head. Anyway, it is explained there in the 7th post under:
https://www.ford-trucks.com/dcforum/exhaust/149.html

 

Actually I thought of changing the rocker ratio and cam but not just the rocker ratio by itself. I want to increase the duration the valves are open and also how far they open into the chamber. However I also want to lifters, rods, springs, valve locks, and valve seals. That's the whole valve train... I know! I don't plan on doing this until the engine needs a overhaul, which is 200,000 miles down the road. YEESH! That's going to be a longtime, but hopefully something fun to do when it gets here! Wooo hooo!

 

I'm looking at the Clifford Performance catalog, and it lists the Holley 4bbl 390 cfm carb as being for engines of displacement of 150-260 ci. Will this thing still work on my 300? The carb listed for 260-300 ci is a 465 cfm, but that would probably kill my mileage...

Also, what's the address for the offenhauser site? offenhauser.com seems to be an industrial metal fabrication company...

 

I wasn't able to find Offenhauser's website either, but I have their sales department number: (213) 225-1307.

For the variables listed input the following numbers:
Engine size = 300
MAX rpm = 4500
Volumetric efficiency = .8 (This is a representation of a percentage of vm)

The more modified an engine is (camshaft, rocker ratio, ignition modules, intake manifold, headers, exhaust tubing size) the more efficient it is at burning all of the air/oxygen within the combustion chamber. So a value of 1 represents 100%, which is impossible with any engine. Basically the more modified the higher the percentage of volumetric efficiency. So based upon the numerical values I listed above, your 6er doesn't even really need 390cfm of air flow. However as you modify your intake, headers, and ignition, you will easily push this upto .9 or 90%. If you really overhaul it you can get it upto 93% to 95%. Using 465cfm carb will over carberate your engine. It will run in a rich condition, which will kill mpg and pollute the air. Trust me on this 390cfm of air is more than enough for this engine, unless you plan on turbocharging than go for the 465.

 

Thanx again for the help... I'm learning slowly... This is my first truck, but she's a good truck so i want to beef her up good. I want to get down exactly what i'm doing before i start anything...

-Der Meister-

 

 

Offenhauser doesn't have a web site. However, if you want to buy their manifold (new) Jegs sells the low RPM version (1000-5000) for $200 and J C Whitney sells a high RPM version (2500-7000) also for $200 (http://www.jcwhitney.com/item.jhtml?ITEMID=14766). To get to the Jegs one you have to do the following:

1. Go to "www.jegs.com".
2. Click on "Online Catalog" mid-way down on left side.
3. Click on "Fuel Systems".
4. Click on "Intake Manifolds".
5. Click on "Offenhauser Dual Port 6-Cylinder Manifold".

I myself would spend the extra $ and go with the Clifford water-heated version though unless I was going to race it. Even though I don't have experience to back it up, I think it is more "streetable" than the Offy. Good luck.

Will


'84 F150
YFA F/B
SROD
"Ex" => Bone Stock