aluminium head questions

I'm not sure what you need to make for power, but honestly if the 452s are stock ports, you can have them ported for about 1/3 the cost of any aluminum and make the power to run mid 11s. You need about 260cfm to make 475-480hp on a hydraulic cam. That's more than enough for you to exceed your goal with a well matched powertrain. That being said, the MP heads (the "452s, which are straight plug, and have a core plug and an "M" on the ends instead of Edelbrock) are as good as any aftermarket head. They ALL need work and just bolting them on can sometimes be a problem, sometimes they run well enough to meet the owner's requirements. But you will always make better power having a reputable shop check and correct the valve job. Indy, Edelbrock, MP, Source... they all have problems as delivered. Any will make the power you want without porting. The 6bbl does leave a small amount of power on the table, but compared to an RPM they are very similar. If you like a sixpac, you can make the power easy with it. You have to make sure it's tuned and runs properly.