I wouldn't try it. You'll be getting into water pretty quick especially on the exhaust side. If you are going to the 390 stroker I'd personally rather have the 915's. I had 915's on my 75 Dart 4 speed 318 +0.040 and swapped to worked over 302's with a slightly larger cam and can't tell much difference. It seemed to wind up tighter with the 915's actually....