You wanted some sugestions so here they are. For one I am getting really tired of seeing vehicles that are called legal in every definition of the term only to fall short on several areas. Specifically emissions. Its a 1975 Chevelle and a 1975 anything under a 1/2 ton ratin car or truck required some basics from the factory. These items are federally illegal to remove. EGR, PCV, charcoal recirculatory system and anything after 1975 had catalytic converters. I dont live in an emissions testing county in Texas but in Dallas they have adopted almost the same difficult laws as in California. Here are some more basics. If you install a 2007 LS7 Corvette engine into a 1975 car you have to keep the emissions from the 2007 car you got the engine from. So all the pro touring cars are bypassing the legality of thier engine swaps, how I dont know. But it lacks cedibility when I read in all the car magazines how streetable my $50K pro-touring car is and its legal. Its legal cause they all register them as antiques not as daily drivers. Anitiques in texas legally can only be used for car club functions and parades, not as daily drivers.
 So here are my guide lines. Keep it real. I like Foose and Coddington stuff but make it look like we built it. Keep it legal, keep the traditional small block (no 383). Every 383 chevy at the track I see runs like crap so keep a 350 if you want a torque engine build a 400 small block.  Make tons of power!!
 It should look like a carb setup like Nascar but a EFI setup would keep some economy. Maybe an old Holley Projection or something. You could use a Fast XFI but $3700 for a efi setup... Comp cams has enough money all ready. While your at it ask Holley, Edelbrock and Fast how come no one makes a good manifold like the RPM air Gap with an EGR so it legal on my 74 Camaro!
 Make it a standard like a Richmond 5 or 6 speed, stock manuals suck and anyone with any mechanical skill can rebuild a richmond unlike factory stuff. If its going to be a Nascar clone then make it one. A cage would be nice but no really a necessity. Hot Rods to Hell has a cool truck arm rear suspension just like the Nascar boys. You can get all kinds of Nascar stuff, exhaust, spoilers, etc. on ebay.
 I like the satin paint look like you mentioned in the PHR article.
 Aero, Basset and others have Nascar wheels for great prices. And they are actual nascar wheels!!! You can get used tires at the races cheap and use them for the pics when the car is done.
 Dash and interior, it needs to be liveable but ebay has used nascar dashes from real race cars check nascar trucks also. you stated you wanted to drive the car so a/c would be nice.
Exhaust: ebay lots of Nascar boom tubes. Its a must have.  
I like Nascar spoilers and window tabs and straps.
 I want to do an 1974 IROC replica with one of my 74 Camaros but its lots of money for what I want to do. I want a stripped interior with a/c and a radio. A cage, a truck arm rear suspension, adjustable coilovers with weight jacks front and rear. Minilite or Aero wheels.
I allready have a front spoiler for my current car.
 I have Smokey Ram crossram intake on my car right now with an 830 Holley and am working on adpating an EGR to keep it legal.
I guess I need to renuew my subscription to keep tabs on this series. I buy them all anyway.

Nascar should take a lesson. Race cars that resemble whats on the street what a concept.  

The legality issue of some cars could always be called into question, I have seen some so called "street legal" cars that are so far from being true it's not even funny. But heck if people can get them registered, and smogged when applicable why the heck not?  

Yawn......sorry there f-body, I nodded off there three lines into that wine about emissions. Would you like some cheese with that?  

Our Laguna has not one, but two catalytic converters. All the smog gear remains on the car. When we do the engine, it will run cleaner than it does currently, and will have new, high-flow catalytic converters. There is no factory smog pump on our '75, and never was.  

Very cool, that should answer that question I would say.  

Yeah it's not hard to imagine the new motor will run cleaner then the one originally installed.