Thoughts on a 390 cu in. stroker from a 318?

I would never stroke a 318" personally do to the bore size.

To make power in a normally aspirated engine you need room (bore) for the valves to be able move air freely.

I've sold 390" kits, but it would be a far better engine using a larger bore 360/340 block.

Plus you'll then have a 408", or 416". However, having more room for the valves is far more important to me than the extra cubic inches.

Tom