[Steve C.]

I'll stick my neck out and suggest the infamous "Roadpaver" hydraulic roller ( Comp lobe 3115B) with 246 degrees intake duration and .4000" lobe lift in conjunction with solid roller lifters won't do it, not 660-670 horsepower.

ET/MPH = HP http://www.wallaceracing.com/et-hp-mph.php

Anybody out there with actual dyno numbers ?


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[Steve C.]

Less cfm airflow involved but here are power numbers from a actual engine dyno sheet....

4.250" stroke, 4.180" bore, 305 cfm alum d-port heads, Torker II intake and 950 carb and the 246/252 "Roadpaver" hydraulic roller cam using solid roller lifters with a 1.52 rocker ratio. It made 589.7 hp at 5800 rpm. A long way to go to make 660+ hp.

[72LuxuryLeMansLa.]

Originally Posted by Steve C.

Less cfm airflow involved but here are power numbers from a actual engine dyno sheet....

4.250" stroke, 4.180" bore, 305 cfm alum d-port heads, Torker II intake and 950 carb and the 246/252 "Roadpaver" hydraulic roller cam using solid roller lifters with a 1.52 rocker ratio. It made 589.7 hp at 5800 rpm. A long way to go to make 660+ hp.


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Wow! That cam was done at 5800rpms?

[mike76]

OKay. This is through SD perf. D.B. is supplying everything. for that projected power level. 340 cfm heads, 10.5 cr., specially tooled intake ,etc. I don't have much doubt that through his recommendations I will arrive @ this power level. Again... the original question... Why would one run solids on a hydraulic roller if a set of hyd. lifters will give me more vs the solids(10-12*). I've read here that is the "rule of thumb". What am I missing? Am thinking that the hyd. lifters will give me enough rpm w/o the ultra stiff springs needed for the solid stuff.

[Steve C.]

I believe it was based on Dave Bischopps dyno testing but Cliff Ruggles has reported going to solid roller lifters with about .006" lash on a hydraulic roller lobe will show some additional power at high rpms. The engine will make about the same power thru about 4500 rpms. From there on up the engine will rev a bit faster and peak at a slightly higher rpm. That said, just keep in mind we are not talking about a lot of additional power and not a lot more peak power rpm involved with the change. Harry K has also posted similar results with his chassis dyno testing with and without solid roller lifters on a hyd roller lobe.


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[jonmachota78]

Originally Posted by mike76

Again... the original question... Why would one run solids on a hydraulic roller if a set of hyd. lifters will give me more vs the solids(10-12*). I've read here that is the "rule of thumb". What am I missing? Am thinking that the hyd. lifters will give me enough rpm w/o the ultra stiff springs needed for the solid stuff.

Because without exotic valvetrain components (PDude solution), hyd rollers are going to have ishues above 5800 or so rpm(float, pumpup). You're going to need valvetrain stability more like 6800+ rpm to reach your goals. This puts you square in solid lifter territory. And without having to regularly inspect your lifters i would recomend bushings for the street.

[PONTIAC DUDE]

Originally Posted by jonmachota78

Because without exotic valvetrain components (PDude solution), hyd rollers are going to have issues above 5800 or so rpm(float, pump up). You're going to need valve train stability more like 6800+ rpm to reach your goals. This puts you square in solid lifter territory. And without having to regularly inspect your lifters i would recommend bushings for the street.

I dis-agree thru actual testing both on the street & strip. You need stability with any long duration camshaft.

[ta man]

Originally Posted by mike76

OKay. This is through SD perf. D.B. is supplying everything. for that projected power level. 340 cfm heads, 10.5 cr., specially tooled intake ,etc. I don't have much doubt that through his recommendations I will arrive @ this power level. Again... the original question... Why would one run solids on a hydraulic roller if a set of hyd. lifters will give me more vs the solids(10-12*). I've read here that is the "rule of thumb". What am I missing? Am thinking that the hyd. lifters will give me enough rpm w/o the ultra stiff springs needed for the solid stuff.

You are in good hands trust Dave.