The Gladiator featured a static compression ratio of 10.0:1, or at least it did with the 64cc chambers offered on our RHS Pro Action heads. The 76cc chambers employed on the factory 882 castings dropped the compression by a full point. This obviously had a positive effect on the power production offered by the RHS heads, but running a 10.0:1 compression will actually improve not only power production but also fuel economy. The elevated static compression is still pump-gas friendly, especially given the detonation suppression properties gained by the change over from cast-iron to aluminum, to say nothing of the improvement in combustion chamber design.
It should be noted that the improved chamber design offered by the RHS Pro Action heads actually reduced the amount of ignition timing required for optimum power. This is a good sign, as a reduction in ignition timing will reduce the likelihood of detonation as well. Though a positive step, the hike in compression was accompanied by a serious increase in airflow efficiency. Given the street-oriented nature of the build up, we purposely chose the smaller 180cc ports to maximize low-speed and average power production. Despite choosing the smallest ports, the RHS Pro Action heads offered a solid 50 cfm advantage over the stock heads.
Given its performance street intentions, the Gladiator small-block was also equipped with an Edelbrock Performer RPM Air Gap intake and Barry Grant 750 Mighty Demon carb. The dual-plane intake was chosen over the racey single plane for its superior low and mid-range torque.
If all you need is a set of cast-iron replacement heads, RHS has you covered. If you're looking to build a 400-hp street motor, your choice of headgear will be slightly different. In this case, the ideal choice seems to be the 180cc Pro Action aluminum heads, as despite the mild cam, this small-block had no trouble topping not only 400 hp, but more importantly for the street 400 lbs-ft of torque.
As we mentioned, the Gladiator was first equipped with the stock 882 castings, but not before we upgraded the factory valve springs to allow for the near-.500 lift cam. The last thing we wanted to do was limit the rpm capability of the engine with insufficient valve spring pressure. Equipped with the stock cast-iron 882 heads, the 355 produced 337 hp at 6000 rpm and 352 lbs-ft of torque at 4000 rpm. (The MSD ignition was adjusted to provide 36 degrees of total timing while jetting in the Barry Grant 750 Mighty Demon provided an air/fuel ratio near 12.8:1.) For all testing, we relied on a set of 1 5/8-inch Hedman headers feeding a pair of 18-inch collector extensions.
After replacing the factory 882 heads with the 180cc RHS Pro Action heads, the peak power numbers jumped to 402 hp and an even 400 lbs-ft of torque. The more efficient RHS heads improved not only the peak values, but the power production throughout the rev range, from 2500 rpm to 6000 rpm. Given the impressive power gains and the fact that the heads transformed our 330-hp small block into an honest 400-hp small block, we'd say the RHS heads delivered service with a smile.
Equipped with the stock 882 heads, the mild small block produced 337 hp and 352 lbs-ft of
To compare the effectiveness of the RHS heads, we ran them against a set of stock GM 882 c
The 882 heads featured 76cc chambers and a 1.94/1.5 valve combo.