[mike343sharpstk]

Nice! You are braver than I. The blue and red lines are exactly what I would have done.
I would maintain the stock portion of frame in the yellow reference area and build the new front portion of the frame straight forward from their (where the stock fram was orignially).

Another quick note while I'm thinking of it. The biggest clearance problem in the front will be the front-bottom corner of the wheel opening when the front wheel is turned.
with stock suspension and fat tires on the front you can have that problem if you dial in enough caster. I have only about 1/2" clearance at that location and I have skinny tires by comparison to what you will be using.

Scott, first gen Javelins are a bear to find, but when you do find one the price is usually pretty low. Not a huge fan of second-gen humpster javelins in stock trim, but I do think they look great as road racers/pro-touring cars. The second gen cars are easy to find.