i found the same stuff recently and got all excited. but look at it - it's 90' angles. as pointed out by a few chaps here - it aint gonna flow that good.
i then found a beaut on FABO about modifying a stock cast-iron manifold by chopping out the centre heatbox section and converting to a dual-output.
they guy on FABO who did it is 'waggin'.
i've now got an extra exhaust manifold which i'm going to start chopping up - aiming for dual 2" running side-by-side down the LHS of the car (following stock routing)
it should look ripper with my speco dual Carter BBS intake.
here's a pic of waggin's work:
(image courtesy of FABO -
http://www.forabodiesonly.com/mopar/sho ... hp?t=36378)
waggin, the guy on FABO who was responsible for the above set-up, reports the following:
"the early (1966 and older) exhaust manifolds are made of cast steel (can be welded with a mig welder) 85 chevy drivers side manifolds from a monte carlo are the pieces I used to make the downpipes. I ran 2" true dual exhaust to the rear of the car I was very happy with the performance and the sound,don't know what the performance gain was but it sounded great,and i have over three years service as a daily driver on them and no problems,they are on bruces car now as I have installed a v-8 and four speed..........."