290 pistons

SHHHHHHHHHH!

bore spacing = distance from bore center to bore center, not the diameter of the bore itself

Correct me if I'm wrong but isn't the bore on a 290 3.75 and the stroke 3.28.

jonb79 wrote: ...  I was under the impression a 290 could perform out like a ford or chevy 302 or even a chrysler 318 with some mods...

If you're talking Boss 302 or Chevy 302, those were purpose built engines for racing. They were put in a limited number of production cars in order to be able to use them for Trans-Am. At the time, AMC was using the 290 or 304 and they were competitive.  None of these engines were known as great street performers because they made their power at high RPM.

Nowhere in this thread have you mentioned the purpose of the car. Is it street, street/strip, or race only? That makes a big difference on the engine you build. Street performers really need low end grunt because you can't achieve high RPM for very long. For street/strip you want a wide power band to take advantage of higher RPMs but still have low end for the street. For race only, you have to decide what class you want to be in, then build the engine (and car) specifically for that class.

A guy I know has a 318 in his Dart (street only). It has 340 heads, an upgraded cam, intake, and carb. He says it runs like a 340 and he's right. But that's a lot of work to get it to the level of a stock 340. If he started with a 340 or 360 and did the same work, he would be in the range you are looking for.

Im going to build something for the street and once inawhile at the strip. Most likely going to buy a 360. love that chevy guy comment.