RHS or EDDY

No doubt that cam and carb are holding back what you currently have. Keep in mind that changing that cam might mean you need to replace the valve springs and possibly upgrade to 10 degree retainers and locks. Get the right cam in there with a 750 Holley double pumper and most likely you will be happy. Brian at IMM can recommend a cam for you and his prices are very competitive.

If you have money to burn and wanna go faster hook up with Brian at IMM and get cam and heads. The RHS heads are the bang for the buck winner as far as replacement heads go and the closed chamber will up your compression. The Eddy heads have the benefit of lighter weight and when ported make great power. Their only down side is the additional cost.

Also remember that you can sell off those J heads for a nice chunk of change and get a set of RHS heads ready to bolt on and go. Its more money yes but its easier. If it were me I would swap the heads out because I like closed chamber quench engines.