On late model 5.0 heads ... does anybody know the maximum lift that can be achieved without Rocker arm slot to stud interference using the factory Pedestal Mount rocker arms? Thanks ....
I'm confused. If you have pedistal rockers there is no stud to interfere with. With my GT40P heads the limiting factor is the valve spring stackup, .500" lift max.
The front of the slot in the rocker can hit the pedestal at high enough lift ... I have different springs installed to take car of the spring stackup ...
Best way to find out how much lift you can have with your combination is to measure it. Take a valve spring off and put on a light weight spring. Push the valve down until the rocker runs out of slot and measure at the valve. You should also check for coil bind too. Also, installed height of the valve is a big factor. I read in your other posts that you are having some trouble with broken studs. You SHOULD be able to get away with .500 lift - but you are probably getting close. It could be a fluke thing but I would be looking real hard to rule things out. Cleaver
On pedistal mounts, the rocker arms absolute limit would be the bar mount between two mounting pedistals and depending on the rocker used. The max lift is first determined by the piston to valve clearence, then the spring stacking issue is solved, then rocker interference if there is any. If rocker lift issues are present, IMO there will be problems keeping the rocker tip on the valve and that can't be allowed to even be close to an issue. While I can't say what the max lift could be because it is a dependent issue, most street level heads are done flowing at around .550 to .575 lift. Stock heads are done at less than .500 lifts. This lift range always demands that all aspects be measured and accounted for. Rocker ratios also have to be considered and in some cases spring diameter. Lifting valves beyond the max flow rate of the ports brings with it less valve train reliability and more guide wear over the longer term although is does tend to help flow at the lower lifts. It is better to use cam designs with rapid lift rates and limited max lifts in order to get the max area under the lift curve. This is where roller designs have the advantage.
