Hyd Roller vs Hyd Flat tappet on SM heads

[Cuda416]

I was over looking at the SM heads and noticed they have the fully assembled heads advertised for hyd roller, and hyd flat setups.

My understanding was that rollers needed heavier spring pressure due to weight, but these two pages show what appears to be the opposite.

Mopar Chrysler SB 318 360 170cc 65cc Hydraulic Roller Assembled Cylinder Heads
Max Lift: .600
Coil Bind: .1.150
Intake Install: 135lbs @ 1.8
Exhaust Install: 135lbs @ 1.8
Closed Sear Pressure: 135lbs
Open Seat Pressure: 325lbs


Mopar Chrysler SB 318 360 170cc 65cc Hydraulic Flat Assembled Cylinder Heads
Max Lift: .600
Coil Bind: .1.060
Intake Install: 145lbs @ 1.9
Exhaust Install: 145lbs @ 1.9
Closed Sear Pressure: 145lbs
Open Seat Pressure: 360lbs

These seem to contradict what I've read. Is it just a mistake or is there something I am missing?

 

[MOPAROFFICIAL]

Spring pressure for hyd roller can vary, but usually fall into the 135 seat and 360 open range. Solids..depending on ramp speed and app can be 120 to 160 seat
depends on the cam. Always follow cam manufacture recommendations for spring pressure.

 

[Cuda416]

Spring pressure for hyd roller can vary, but usually fall into the 135 seat and 360 open range. Solids..depending on ramp speed and app can be 120 to 160 seat
depends on the cam. Always follow cam manufacture recommendations for spring pressure.

Thanks MO, but just to be clear, these are both slated as hydraulic lifter heads (springs). I also noticed the spring height is different on these as well. 1.8 (hyd roller) vs 1.9 (hyd flat tap).

 

[rumblefish360]

I almost always throw the springs away and use quality spring pressures for the cam I’m using. I don’t always know where the springs come from on complete heads.

The spring height recommendation is always followed. I don’t care how the head came or with what springs are on it. It all gets adjusted.

Don’t worry about the spring height they state. Both listings are rather tall compared to stock.

 

[PRH]

I highly doubt either of those head packages come with the springs installed at 1.900”.
I’m not saying it’s impossible, just not likely.

 

[fishmens67]

almost always throw the springs away and use quality spring pressures for the cam I’m using.

I also toss the valve keepers, I want to personally remove them from a Comp package.
Valve seals are usually junk too.
oh heck I'm going through the whole assembly.

 

[Cuda416]

Sounds like the best bet is to get the bare heads and start with that .lol

 

[Cuda416]

Thanks guys, your input is always appreciated.