I run a 305 in my chevy and had it bored out to 315 ci which gives me a better chance of larger heads. What I meant on the 283 was it was and is still a good engine but not one that you could realy build up to the HP you want. I had one in my 56 chevy and I loved it and it was rated at 240HP and I blew the doors off many cars because I could wind it up to 6500rpm with no valve float. I truly loved that motor but went on to better thing like a 348.