| Aluminum Pro Action Heads |
| RHS Part No. | Intake Runner & Chamber Size | Valve Size Int/Exh | Application | Power Expected |
| 35001 | 180 cc/64 cc | 2.02 in/1.60 in | 302/351 ci
Street | 325-400 hp
1,500-6,500 rpm |
| 35002 | 200 cc/64 cc | 2.02 in/1.60 in | 302/351 ci
High RPM
Street/Race | 400-550 hp
3,500-8,000 rpm |
| 35003 | 215 cc/64 cc | 2.08 in/1.60 in | 347-421 ci
High RPM
Race Only | 550-650 hp
4,500-8,500 rpm |
| 35004 | 180 cc/58 cc | 2.02 in/1.60 in | 302/351 ci
Street | 325-400 hp
1,500-6,500 rpm |
| 35005 | 200 cc/58 cc | 2.02 in/1.60 in | 302/351 ci
High RPM
Street/Race | 400-550 hp
3,500-8,000 rpm |
| 35006 | 215 cc/58 cc | 2.08 in/1.60 in | 347-421 ci
High RPM
Race Only | 550-650 hp
4,500-8,500 rpm |
| Cast Iron Pro Action Heads |
| RHS Part No. | Intake Runner & Chamber Size | Valve Size Int/Exh | Application | Power Expected |
| 35301 | 180 cc/64 cc | 2.02 in/1.60 in | 302/351 ci
| 325-400 hp
1,500-6,500 rpm |
| 35302 | 200 cc/64 cc | 2.02 in/1.60 in | 302/351 ci
High RPM
Street/Race | 400-550 hp
3,500-8,000 rpm |
| 35303 | 215 cc/64 cc | 2.08 in/1.60 in | 347-421 ci
High RPM
Race Only | 550-650 hp
4,500-8,500 rpm |
| 35304 | 180 cc/58 cc | 2.02 in/1.60 in | 302/351 ci
Street | 325-400 hp
1,500-6,500 rpm |
| 35305 | 200 cc/58 cc | 2.02 in/1.60 in | 302/351 ci
High RPM
Street/Race | 400-550 hp
3,500-8,000 rpm |
| 35306 | 215 cc/58 cc | 2.08 in/1.60 in | 347-421 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.