July 19, 2006

Aluminum Pro Action Heads
RHS Part No.Intake Runner & Chamber SizeValve Size Int/ExhApplicationPower Expected
35001180 cc/64 cc2.02 in/1.60 in302/351 ci
Street
325-400 hp
1,500-6,500 rpm
35002200 cc/64 cc2.02 in/1.60 in302/351 ci
High RPM
Street/Race
400-550 hp
3,500-8,000 rpm
35003215 cc/64 cc2.08 in/1.60 in347-421 ci
High RPM
Race Only
550-650 hp
4,500-8,500 rpm
35004180 cc/58 cc2.02 in/1.60 in302/351 ci
Street
325-400 hp
1,500-6,500 rpm
35005200 cc/58 cc2.02 in/1.60 in302/351 ci
High RPM
Street/Race
400-550 hp
3,500-8,000 rpm
35006215 cc/58 cc2.08 in/1.60 in347-421 ci
High RPM
Race Only
550-650 hp
4,500-8,500 rpm

Cast Iron Pro Action Heads
RHS Part No.Intake Runner & Chamber SizeValve Size Int/ExhApplicationPower Expected
35301180 cc/64 cc2.02 in/1.60 in302/351 ci
325-400 hp
1,500-6,500 rpm
35302200 cc/64 cc2.02 in/1.60 in302/351 ci
High RPM
Street/Race
400-550 hp
3,500-8,000 rpm
35303215 cc/64 cc2.08 in/1.60 in347-421 ci
High RPM
Race Only
550-650 hp
4,500-8,500 rpm
35304180 cc/58 cc2.02 in/1.60 in302/351 ci
Street
325-400 hp
1,500-6,500 rpm
35305200 cc/58 cc2.02 in/1.60 in302/351 ci
High RPM
Street/Race
400-550 hp
3,500-8,000 rpm
35306215 cc/58 cc2.08 in/1.60 in347-421 ci
High RPM
Race Only
550-650 hp
4,500-8,500 rpm

As you can see, RHS has a wide variety of cylinder heads for small-block Fords. Expected horsepower, according to RHS, is the same with aluminum and cast iron. However, it is our belief horsepower numbers will be lower with cast-iron heads because they don't have the same kind of heat transfer as aluminum heads. As a result, horsepower won't be as high. Cast-iron heads are also heavier than their aluminum counterparts.