Personally I'm not a fan of the LMC billet grille things. I'm not sure if your asking my opinion on what would look better, but if I wanted to do quad headlamps, I would definitely do it in the stock grilles. HIO posted a picture of that, and I'm on the fence bout it

 

I was talking about the location of the twin lights idea, like this...



or this



What about using the upper venting area above the grill inserts for your ducting location?

 

Only the outboard slots will work for "ram air". There's that thing called a radiator in the way of the others.

Why not duct the air from under the inner fender with the inlet behind the headlight area?

 

I haven't decided 100%, but here's the theory if my math holds up

AC (air capacity in inches per minute) = rpm * displacement / 2

So at idle

AC = 700 * 390 / 2
AC = 136,500

So at idle the engine wants 136,500 cubic inches of air.

A ram air system consisting of two 5 inch inside diameter will also be around 30 inches long (if not a bit more).
Volume of a cylinder = 3.14 * r^2 * h
V = 3.14 * 2.5^2 * 30
V = 588.75

So one tube will support 588.75 (at zero mph and no vacuum) cubic inches of air at any given point.

so in theory 588.75 * 2 * 60 (assuming the vacuum will pull the whole volume of the tubes each second)
70,650 cubic inches of air. So the big question, are those inlets big enough? Will the engine pull more because of the amplified vacuum? Or is there simply no way to cram enough air through a 390s throat at that speed?

And I would consider going through the fenders, but I really don't want a whole bunch of road grime kicked up

 

For a ram air effect? That's a good question. There was an article in Hot Rod or Car Craft's 'Vettehack' where they hooked up leaf blowers to the intake system. Ya might want to read that article for some background and theory on ram air systems.

One of the goals of ram air is to charge the intake with cool dense air which holds more oxygen molecules than warm (light) air. That, in turn, results in more power.

I think you misunderstood my statement "duct it through the fenders" - not duct it from the fenders. Meaning, there would be a hose from the air cleaner to a flange on the fender and then another hose (or tube) routed under the fender which sources fresh air from behind the headlight area through the core support. IIRC, 1957 Chevys sourced fresh air for the interior using the headlight bezel.

 

I think HIO is talking about something similar to this


My uncle did a setup like this (replacing an inner headlight with an intake horn/funnel) in the '74 Alfa Romeo GTV he built for my aunt. There is a hose connected off this "funnel" that goes to the air filter at the turbo inlet. It's just a way of bringing cool air from out in front of the car in. Keep in mind in dusty/dirty/rocky situations a truck can be in, this could be somewhat bad. My uncle has some stainless mesh in the intake horn.



Now back to the original topic of the thread. I've looked at the mesh thing for the grills and to keep the 74-75 grill style it's a bit of work. I fabricate all sorts of stuff on all my projects & I ended up keeping and cutting the grill inserts on my '74 crew vs. fabricating new from scratch. I've done a LOT of cutting to keep them & it's taken quite a bit of time to do it nicely, but it's still been much less effort than building from scratch.

I only have 1 grill insert done here, but it kind of gives you the idea. There is about 1/2" thickness left on the bottom of the grill insert & it tapers wider at the top. This is because the grill in stock form is closer to the radiator at the bottom than the top.

 

10-4 ChaseTruck. Dats whattumsayin....

 

i frenched some amber Hella 500s (**** hair less than 7" diameter) into the grille, came out really sweet. i need to mount tabs to the core support though, the stainless grille shell isn't quite strong enough.