Hi guys. I have a 67 barracuda. Finished building a 340 for it but it has a funny vibration that shakes the car between about 2300-2800 rpm. I should have had the rotating assembly balanced. Anyway, I'm going rebuild a 273 right and save the 340 for a future product. I don't want to screw up designing this motor and am hoping for some help. I want to maximize performance. Car has 727 with 3.23 sure grip and 68 hi po exhaust manifolds. I have some 302 castings I was planning on using. Wanting to generate about 275 hp. Any comments appreciated.

Greg