Engine Got a Street Car and Turning Your Hyd Roller to 7k RPM?
- Thread starter qikgts
- Start date
I'll answer your questions, and I'm sure lifters are a reasonably important part, but I think that's possibly less important than the entire valvetrain combo. Ramp rate, spring pressure, and lightweight parts have more to do with it IMO, but I'm an amateur that can put parts together, not a pro.
I run link bar lifters that I don't know the brand of & probe shaft mount rockers on Father Time, my turbo 331, and have spun it to 7k many times without any issue. That's where I set the limiter now, and I try to shift at 6,800. When I was testing with it, I originally limited it at 7,200 RPM, but I can tell the torque is falling off, and that's pushing it to the point I'm not comfortable. So, I pulled it back to 7k. Of course, I told Ed that's what I wanted to do, and he prescribed the cam & spring package, too. It's a mild reverse split 228/224* with .600"-ish lift cam and the preferred spring pressure is 155#-160# on the seat.
Conversely, in my other car (Grover), I overspun on an unintentional 3-2 shift in a race and paid for that with a new set of pistons & a rebuild, recently, too. I do NOT believe it eclipsed 7k RPM, or if it did, then it didn't by much. As soon as I heard the RPM going the wrong way, I was clutching again. But, a valve caught the piston in the number 2 cylinder and bent it. Fortunately, the piston survived without coming apart. It has some really nice T&D shaft mount rockers, link bar lifters & since they were high-end builds at around the same year they're probably the same ones as in Father Time, and I could not find any spring pressures for the original cam. They may have just been whatever came on stock AFR205s. The point is that the same lifters had two different results at 7k RPM, and I really wish I had the spring specs on this one to validate my suspicion.
I'm not looking to do it, but the build I'm planning to put into my daily driver, Black Jack, would almost definitely go there, too. I'd be flabbergasted if it wouldn't. I've collected Morel Link-bar lifters and Comp Cams Ultra-pro Magnum Rocker Arms with lightweight tool steel retainers, hardened locks, and heavy wall push rods for stability. That said, I think it'll be out of air over about 6.5k, which is intentional as I don't want to rev a 2-bolt OEM block any higher, even though some do survive up there. My goal is to make the most 'area under the curve' with a 6.5k RPM limiter. So, I'll likely look to shift at 6,400 RPM. With a different intake, and especially with some carb intakes, I'd expect it to make power well past 7k+.
I run link bar lifters that I don't know the brand of & probe shaft mount rockers on Father Time, my turbo 331, and have spun it to 7k many times without any issue. That's where I set the limiter now, and I try to shift at 6,800. When I was testing with it, I originally limited it at 7,200 RPM, but I can tell the torque is falling off, and that's pushing it to the point I'm not comfortable. So, I pulled it back to 7k. Of course, I told Ed that's what I wanted to do, and he prescribed the cam & spring package, too. It's a mild reverse split 228/224* with .600"-ish lift cam and the preferred spring pressure is 155#-160# on the seat.
Conversely, in my other car (Grover), I overspun on an unintentional 3-2 shift in a race and paid for that with a new set of pistons & a rebuild, recently, too. I do NOT believe it eclipsed 7k RPM, or if it did, then it didn't by much. As soon as I heard the RPM going the wrong way, I was clutching again. But, a valve caught the piston in the number 2 cylinder and bent it. Fortunately, the piston survived without coming apart. It has some really nice T&D shaft mount rockers, link bar lifters & since they were high-end builds at around the same year they're probably the same ones as in Father Time, and I could not find any spring pressures for the original cam. They may have just been whatever came on stock AFR205s. The point is that the same lifters had two different results at 7k RPM, and I really wish I had the spring specs on this one to validate my suspicion.
I'm not looking to do it, but the build I'm planning to put into my daily driver, Black Jack, would almost definitely go there, too. I'd be flabbergasted if it wouldn't. I've collected Morel Link-bar lifters and Comp Cams Ultra-pro Magnum Rocker Arms with lightweight tool steel retainers, hardened locks, and heavy wall push rods for stability. That said, I think it'll be out of air over about 6.5k, which is intentional as I don't want to rev a 2-bolt OEM block any higher, even though some do survive up there. My goal is to make the most 'area under the curve' with a 6.5k RPM limiter. So, I'll likely look to shift at 6,400 RPM. With a different intake, and especially with some carb intakes, I'd expect it to make power well past 7k+.
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Johnson and Morel linked lifters are going to be your best bet. Several folks are turning them past 7000.
What you have to ask yourself is how much money do you want to spend? Like FastDriver pointed out you are going to need some quality valve train and then will need a cam profile to take advantage of it. My 331 will pull well past 6800 but everything starts to fall off at 6400 so no reason to push it past that. Other issue is no matter what the displacement (although it gets worse with strokers) a stock roller block does not like high rpm. Can it support high rpm? Sure but the question is not if it will come apart it just a matter of when it will come apart when turning high rpm.
What you have to ask yourself is how much money do you want to spend? Like FastDriver pointed out you are going to need some quality valve train and then will need a cam profile to take advantage of it. My 331 will pull well past 6800 but everything starts to fall off at 6400 so no reason to push it past that. Other issue is no matter what the displacement (although it gets worse with strokers) a stock roller block does not like high rpm. Can it support high rpm? Sure but the question is not if it will come apart it just a matter of when it will come apart when turning high rpm.
This is largely my experience with hydraulic lifters. Sure, you can rev to 7k but you're not making any power there.
