I am working on a 59 fiesta wagon that has a 65 model 425 bbo. I’ve ordered a Edelbrock 2151 performer intake and a 750 Holley carb vacuum secondary electric choke. Other than that the motor is bone stock to my knowledge. This car will be a cruiser and keep the patina look with a nice set of wheels. I’m wanting a decent “sound” any recommendations on manifolds or headers, a cam, and exhaust sizes and mufflers would be greatly appreciated.

 

Any cam would have to be special ordered as the 1965 425 would have been a 45 degree block. 455 39 degree cams will not work. To determine cam, and intake, you'd need to know the weight of the vehicle and the rear axle ratio. Also if you are doing the cam, you should replace lifters, pushrods, and rocker and pivots. If nothing else is done to the motor, you would not want anything to radical as you don't want to blow up or over rev the motor. Also it would also be a good idea to change the 50 year old valve springs and have the heads checked too. If that's beyond your budget, I'd just add a performer manifold (or keep stock one), real dual exhausts with flee flowing mufflers like TurboMax.

 

Your idea of "decent sound" may not be the same as someone else's. I sugest talking to Comp Cams tech line about their options, such as high energy, extreme energy, thumper cams etc. Their custom grinds don't cost much more than off-the-shelf stuff,