The 73 RSR bumper fit much tighter than the later IROC and RSR, but the front trunk pan was modified on the factory cars

I had a heck of a time fitting a cooler behind mine.
The later impact bumper has much more room

But if you do pull it in tight, these pictures of my 73 might be good reference of whats going on behind it using a replica of the factory duct


Here are some pics (part available commercially from TRE)
...and her his the build thread http://forums.pelicanparts.com/porsche-911-technical-forum/626050-saving-73-crusher-11.html
http://forums.pelicanparts.com/uploa...1317599781.jpg

http://forums.pelicanparts.com/uploa...1317599380.jpg

http://forums.pelicanparts.com/uploa...1317599922.jpg

I actually created a recessed slot at the top to push the cooler in even tighter
(this is the outside underside front view)

http://forums.pelicanparts.com/uploa...1317697853.jpg

I like your ideas.

I've always thought the original look sort of like a shoebox and could use some refinement.

I’m also building a similar style duct, but a but bigger. We have more tub area on the impact bumper cars.

Here’s the radiator I’m fitting that just arrived today.


http://forums.pelicanparts.com/porsche-engine-conversion-tech-forum/1019879-76-porsche-912-subaru-2-5-swap.html








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