The shockies are staggerd on the post 1970 unibody Falcon based Fords. That may be an issue, but most Boss Mustangs had duals and staggerd shockies.
The exhast header should be the dual out Cliffy or Hooker set up, or perhaps the or a Pacemaker style offered by FSSP, modified to clear the 250 starter. There are a couple of ackward methods to getting a good dual set up past the trans.
Option 1 Take from the two outlets header one pipe under the passengers seat, then under the C4, then linked by an H piece. All V8 Granadas had a twin bump cross member, and its the same with my Falcon 500 as it is with the Monarch. The other pip is in the stock position.
Then run a set of duals all the way to the back.
Option 2 is to group both pipes from the header, and try fitting it under the x-member bump of the true right. There isn't a lot of space, as the bump is only suitable for one 3" pipe, max.
Then run them side by side with an H or x pipe back to duals.
If you have the space and work ethic, I'd just get junked Granada bits, and weld them up with flanges, no interferance fit or U-clamps. I see no reason to go for any really big pipes. The rule for exhast sizing is no more than 1 square inch of pipe area for every 35 cubes for a wicked hot rod, 1 square inch per 50 cubes as a minimum.
Thats duals with a 2.125" internal diameter, or 1.75" internal minimum.
Its common for most cheaper factory spec after markets to be 1.875". Like stock Falcons over here with the optional dual exhast.
Focus on the bends over the axle. Go to flanged 2.25" internal diameter bends over the axle if you can get them, and good dual mufflers. Resonators (Cherry Bombs, Purple Hornies or whatever you call them over there) , facing the wrong way with the internal rough section facing away from the spent gasses, make for a smooth sound. Twin cats in good shape could do the same. The back dual mufflers then take the sharpness off the resonators. The objective is to run smaller pipe sizes with less backpressure by easing the bends. I've seen my mates twin 2.5" 350 63 Chev take a huge loss by having to use 2" exhast pipes. Its better to go cheap on the main pipes, and spend big on the bends. That way, the set-up sounds good, and won't take a curb out or get smashed by pot holes.
The details are up to you, but after researching the Aussie, British Jags, Aston in liners and American ideas on exhasts, this looks like the best method.
Big singles look like they reverberate too much, like a big Tuba. Ask Jack Collins and others from the 300 brigade. The bigger pipes deepen the noise, smaller ones raise the pitch. What Ws111 said on the x-pipe, and use as much off the shelf stuff you can get.
I hope to detail my exhast system for my Falcon 500 soon. This is what I'm using.
arctic circle eh...i sure do love this chilly 23 deg celcius...(sorry i dont have a conversion calculator anymore to convert to farenheit, lol)
