306 question

Discussion in 'Fox 5.0 Mustang Tech' started by TrophyHead, Dec 4, 2003.

  1. What kind of machine work does it take to make my 302 a 306? He mumbles.....
    Can you keep the stock pistons?

    Also are AFR 185's too big for a 306? Thanks
  2. It means a .030 overbore on all the cylinders. no you can not keep the stock pistons, you need pistons .030 bigger than stock.

    185s can be good for a 306 that will see some significant time at the higher RPM ranges (4000-7500). They would be too big for a stock 302-mild 306
  3. 185's aren't really necessary until you start signficantly increasing the cubes, adding forced induction, or building the car to scream at higher RPM. I'd stick with the 165's on a naturally aspirated 302 myself. They'll still flow right up to and beyond the 6000rpm mark and provide much more useable low end torque for the street.
  4. Is it possible to get a N/A 302 to go low 12's in the 1/4?. Or am I dreaming? Thats my goal. But I just thought I would have to go the 306 route with good heads and a crazy cam.

    Any advice I want something fast and reliable
    I want to stay away from power adders for now.

    I just want to see my engine options.
  5. Well, fist off, unless your engine’s tired or in desperate need of a rebuild. Boring it out and building a 306 is going to give you next to nothing for power. If you’re going to spend that kind of money on an engine build to increase displacement, you may as well go all out and run with a 331/347 kit. At least that way you’ll realistically be able to get near those numbers. That being said, low 12,s in a naturally aspirated 302 is possible, but it wouldn’t be a fun car to drive on the street. To make that kind of power is going to require a lot of cam accompanied by a considerably larger head and intake combo. Sounds good in theory, but when you move the powerband up like that, you really kill the low-end torque. The end result being a car with little or no guts on the bottom end, with a peaky powerband and driving manors to match. Not to mention that it’s going to be considerably hard on gas. You’re either going to have to set your goals a little lower, or add juice, displacement or forced induction. Some guys are going to chime in here and say they’ve done it, but I’d bet dollars to doughnuts that they’re experiencing some of, if not all of the problems I’ve stated above.

    Also unless you’re willing to do it nearly all with nitrous, you’re going to have to convert you’re car to Mass Air in order to compensate for such huge changes in breathing capability or a “crazy cam”. Either way…it doesn’t take a crazy cam to make those numbers, it takes a properly matched cam. Bigger isn’t always better.