Heres a Video of my 72' Dart 318 with just a 4bbl holley and dual exhaust from the manifolds. the rest is 2.76 gears and stock old 904 tranny..
From the single stock exhaust and carter 2bbl to the 4bbl Holley and 2 1/2" duals from the manifolds it increase my 0-60 time from 9.2 seconds to 7.1 seconds as seen in the After video. you could probably excpect the same or very close results. As for HP id say a 20hp increase or so to the wheels compared to stock.
2bbl Carter and stock exhaust :
http://www.youtube.com/watch?v=9Vwdapylujs
4bbl Holley and dual exhaust :
http://www.youtube.com/watch?v=9Yh9s3HQap0
My Wifes Ramcharger with a stock 2bbl, single plane intake, and 70 truck manifolds will outrun your dart 0-60, with a crane 270 low lift 119$ cam and lifter set cam........ (3.55 gears may have some to do with that, but it is still a heavy brick)
The stock 318 cam is too small for gas mileage even.
No joke.
the engine is not in the car yet. i just done all the stuff i said i have in. so thats why i said about the cam because its already out of the car, well and because all the people think i wanted a cam and really i just wanted to know how much horsepower ill get from my "stock 318" HAHA and i know it didnt come stock way bck when with ported heads? so no not stock lol
Do you have pictures of the porting?
When someone tells us that they have a 4bbl, headers, and porting, and they are running a stock cam, of COURSE were going to want you to change the cam! It's the difference between 150HP at the wheels and 200+......
Makes sense to me.
Here's my next question, is the cam possibly a roller?
The stock flat tappet cam in those years, was like 240/248, with 400 lift. The lobes were spread out for passing the sniffer test.
Like putting a 6" lift on your Ford Hi Boy, and running 215's........
But you got your HP answers at first.
I would say no matter what you do short of NOS/Boosting it, no more than 170. :-D