I have a 1966 Mustang with a straight 6 so far I have replaced the 1bbl carb to a 2bbl carb. I want to keep the straight 6 but I would like to get a little extra horsepower. When I have the body work performed the engine is comming out. This is when I plan to rebuild the engine. First I would like to have a intake manifold made for a 2bbl carb so I don't have to use a adpt plate.Second should I bore the engine cyc 30/40 over or keep the engine the way it is. From what I can tell the engine is orginal to the car.So far I replace all the front and rear suspension changed the brakes to disc and 4 to 5 lug. Also the 3speed manual to a t-5 5 speed. My car still has the 7.25 rear axel. With out changing the rear end and installing a 302. Which way is the best way to rebuild the engine ang give it the extra horsepower with out putting a 302 in.Any help with web sites or part number would be outstanding.
The intake manifold is part of the cylinder head so changing to a 2 barrel intake is impractical, unless you change the head.A dual or single exhaust exhaust header, a free flowing system and the exhaust port divider for the middle cylinders will help a lot. The stock exhaust manifold, small pipes and muffler strangle these engines.You can remove the engine fan and install an electric one with a thermostat.The exhause modifications and electric fan will free up horsepower and improve mileage. Synthetic lubricants in the engine, transmission, and rear end should help but probably not enough to feel it. It can't hurt and you will be providing better lubrication.If you want to spend some money on it, there have been numerous articles about hotrodding these engines. Many of the modifications (cylinder head) are expensive.That rear end is gimp but I would run it until it makes noise or dies. Then put an 8" from a V8 car in it.Good luck.
Bill1966 coupe1995 Cobra R
Thanks for the input these were two areas that I was thinking of going down the road.