Well I have yet to start my rebuilt SBC 350 but I have a very mild cam and I read about the 1.6 rockers on the exhaust in the site called Ryan's Dyno runs. I have so far kept the 1.6 rockers on both intake and exhaust but I may later put 1.5 roller tips on the intake and keep the 1.6 roller tips on the exhaust. I am planning to turn the engine over by hand and watch the pushrods in the head guides. I have the lowly 882 SBC heads from a '76 Corvette which was a very detuned model but I had the exhaust ports smoothed out by a professional and those heads look like they are pretty good for low rpm torque which I will need for my OD 4th gear. Anyway what you might want to know is that these heads have oval guide holes for the pushrods and the question is whether with the higher lift the push rod rubs against the side of the hole. Some folks on this Forum say that can be a problem which requires taking the heads off and grinding the bottoms of the pushrod holes slightly. I am hoping not to have to do this and so I will just inspect the push rod motion and see if there is any contact with the edge of the hole. Point two is that even if I see interference with the pushrods I will switch to all 1.5 roller tipped rockers because the reduction in friction is supposed to lead to cooler oil temperatures since the stock rockers really rub across the valve tips. A third point is that maybe the 1.5 roller tipped rockers are still slightly better for lift than the stock lifters because measurements on the stock lifters show that they often do not produce the full 1.5 ratio, so a compromise is to use the 1.5 roller-tipped rockers for slightly more lift and cooler oil, but I will try all 1.6 first.

Don Shillady
Retired Scientist/teen rodder