572 Hemi roller cam input

[has2bmopar]

Would appreciate some input from those with experience on running a solid roller in a Gen II Hemi.

Have been hearing horror stories on flat tappets wiping off lobes, even with the oil through lifters, supposed racing oil with good zinc levels, additives etc.

I thought I could avoid problems running a moderate solid roller. I ordered a custom ground from Crower that was to be .650"/.655" with the lash deducted.

I got a call back and they can't grind that much off as it will get past the heat treat depth. They can only go as far as .450" lobe lift, which I believe puts me at .720"/.698" - .700"/.676" with the lash taken out. The open spring pressure will be 700 lbs...

I inquired about a solid flat tappet then and he asked about the rest of the engine and said he recommends the roller. They also pushed the needle roller over the bushed roller lifters. I'm in disagreement there for sure, so I wanted some input from someone that has had experience, good or bad with .700" lift roller cam longevity.

Here's what I have so far...

Crower
272°/278° @ .050"
306°/314° adv
.720"/.698"
108° centerline

Mopar megablock, sonic tested excellent.
4.5" Eagle crank and rods
Ross 10.5:1 custom pistons
Indy/Canfield Hi Po heads 2.4" intakes
Near 480 cfm @ .700"
Indy rockers 1.6 intake/1.55 exhaust
Stage V intake w (2) 750 Edel/AFBs
TTI 2.25" primary with 3.5" collectors

'70 Runner with 3.54 Dana
90/10 street/strip

 

[dvw]

It's not the lift that creates issues. It's the ramp speed. If the lobe profile isn't radical you won't have issues. Either way you need good lifters. I use Isky bushed lifters. Though I don't street drive mine these lifters have over 700 passes on them. The cam is fairly aggresive, 285/[email protected]" with .471 " lobe lift. It also has fairly stout numbers at .200" lift. The motor has good parts. T&D rockers, 7/16" pushrods, Jesel belt, Pac springs retainers and locks. Runs 7100-7200 every pass. Hasn't hurt any valve train parts with this set up. With the general low rpm on the street you really shouldn't have any issues.
Doug

 

[Hemirunner]

I’ve run a similar cam in a 572 hemi. Yours should be a good match to the gear and compression. As DVW says, it’s ramp rate that can be an issue. If the ramp rate is slow enough, you won’t need a ton of spring pressure and it won’t kill a needle bearing roller lifter. I ran Comp 892-16 lifters for years in that engine. I now run BAM bushing lifters in my turbo 540 Hemi but I turn it 7600 regularly and street drive it.

 

[INTMD8]

Does your megablock have bushed lifter bores? Mine isn't and I had to be very careful.

Before I ordered the cam (cam motion low lash solid roller) I measured the reliefs in the oil galleries to decide base circle and lobe lift. With .428 lobe lift on the intake it's .100 away from uncovering the oil gallery on both the base circle and at peak lift.

That is with a Morel black mamba lifter. (not needle bearing, dissimilar metal axle)

 

[PRHeads]

My advice is to be very honest with yourself about what you’re looking for out of the vehicle in terms of use(miles per year) vs maintenance.
Then assess how the parts you’re talking about running in this thread align with those goals.

 

[Charger 770]

As others have stated, lobe ramp speed is the spec to watch. Your basic combo is nice and very similar to mine. A little more gear would be nice depending on your tire OD. I would be using less cam and less spring for what you are trying to do.

I've have found that for lifter longevity on a dual purpose ride, at .200" of lift, the duration needs to be under 200 degrees. Lobe intensity needs more spring than you want on a 90/10 street/strip car. Depending on installed height, 230-250 seat - 650/680 lbs max is what I'd be shooting for like a PAC /Comp 943.

The lobes below would be ideal for what you are trying to do and still make very good power.

Lastly, on a 90% street car, I would use a 112 LSA, it'll make more vacuum, idle better with a lot more initial timing and still make really good power.

If you need more info, PM me.

 

[has2bmopar]

Greatly appreciate all the input... Thanks

I have had my '70 Runner since I was 21 and had a different '70 when I was 14 and a '69 I still have that I got when I was 15. These cars have some serious Imprinting on me in much less stressful times in the late '80s. I had a lot of great times in my current '70 with a 440 with a 509 purple shaft. Seriously doubt it was 470 horse, but tons of fun.

I have recently read more bad stories about big roller cams on the street over a solid flat tappet. I tried to get the smallest roller cam that Crower would custom grind... They said it still required 700 lb open pressure. To me that is a lot of stress on many parts for a street car. Not sure what the Indy iron rockers can withstand either... With input from here as well as my gut saying to tame it down a bit, I am going back to the solid flat tappet.

I believe an Eagle crank and rods have a safe range up to 800 hp. Honestly I don't need to squeeze everything out of this thing, but I do want something that is big enough to utilize the heads and pull peak power up close to 6,000 RPM.

I put a Lunati solid flat tappet 259°/267° .625"ish net lift in a 493 with CNCd Indy 325cc heads and it peaked at 5,800.

Open to opinions on this Crower FT for the 572 Hemi...
280°/282° @ .050"
318°/324° adv
.406"/.412" lobe lift
.650"/639" gross lift
.022"/.024" lash
106° LSA (no power brakes)

Crower oil through, or Barton pushes the tool steel lifters... ?

 

[PRHeads]

Open to opinions on this Crower FT for the 572 Hemi...
280°/282° @ .050"
318°/324° adv
.406"/.412" lobe lift
.650"/639" gross lift
.022"/.024" lash
106° LSA (no power brakes)

For anything that’s primary use will be on the street......my choice for a cam would look nothing like that.
Make sure you understand what a cam like that will behave like in a street environment with closed exhaust.

 

[has2bmopar]

I have several vehicles to build in various ways. This 572 Hemi needs to run good for what it is. I certainly am not worried about a rough idle and I want it to have enough duration to pull peak power near 6,000 RPM.

The 493 with 259°/267° peaked at 5,800. Long strokes take a lot of duration.

The 259° ÷ 4.15" stroke is the same ratio of duration as 280.8° with a 4.5" stroke. It will even be less because the lash is more on the Crower cam. The 106° LSA is on the mean side, but I'm not concerned about vacuum, or idle quality. I just need enough to keep the metering rods down. As far as the exhaust, it will be 3.5" with an X and dump before the axle.

The 509 Purple shaft has a worse duration to stroke ratio in my 440. The duration at .050" is 248°. With a 3.75" stroke it would be the same ratio as a 297° duration @ .050" cam with a 4.5" stroke and you can add about another 10° of duration to a solid to get similar manners in a hydraulic cam with zero lash. The 509 had 4.5" of vacuum and I had to put a light spring on the air grabber door so it would open. Have a friend with a .590" Mopar solid with 271° @ .050" in a 440 and with the converter and lower gears, he said it isn't bad at all to drive on the street.

This engine will eventually end up in my '69 Runner with a cage and relocated springs, as it had the shocks shoved through the trunk floor in an evident Dukes of Hazzard landing. My '70 Runner and '70 GTX will not get any body modifications other than frame connectors. Both will get 493s with better street manners.

It has been my observation that a wedge has a torque advantage in a tamer engine and there is no doubt that a Hemi shines on the high end. I don't want to take away from the nature of the beast any more than I have to. I'm not locked in on that particular Crower shelf cam. I just was hoping for some input of those that have been there, done that.

 

[PRHeads]

If you’re comfortable in your assessment of the cam requirements for your combo, and feel that cam will meet them.......then go for it.

As I’ve gotten older, my tolerance for rowdy cams that exhibit particularly poor street manners has dropped off sharply.

In my view, the MP 590 cam in a 440 would be more appropriate for a strip/street combo that was leaning like 60-70%(or even 100%) towards the “strip” side......where the cars ET played a big part in the decisions involving the overall package........and if that meant the street manners suffered, so be it.

 

[INTMD8]

Just my opinion but you couldn't pay me to run a solid flat tappet in something like this.

You can't compare peak hp rpm from duration/displacement from wedge/hemi.

It doesn't translate.

For example, my 438ci hemi with 262/262 @.050 .658/.612 lift makes peak hp at 7,250.

I have an old Ferrari that's a 213ci V8 with 238/252 hydraulic cam that makes peak hp at 8,200.


There's more to where an engine makes peak hp than just the cam.


Considering 90% street 10% strip and 3.54 gears I would do similar what I did for my own car but scale it up a bit for the added displacement, and I would add compression.

 

[Charger 770]

Get Comp to grind you this cam, used bushed roller lifters, run clean oil, run PAC /Comp 943s with either tool steel or Ti retainers and call it done. You can tighten up the int/exh lash a little on the street, it will be fine.

The lobe design won''t beat up the valvetrain and net lift will be around .640" int/.620" exh

Specd by Dwayne Porter, makes great power and proven to last.

 

[has2bmopar]

Thank you...

That is really close to what I tried to get through Crower. They later called back and said they couldn't grind smaller than a .450" lobe and then shortened the duration which would make the ramps even steeper.

My block does not have bushed lifter bores, so I do want to check the oil passages and confirm the base circle requirements, as INTMD8 has brought to my attention. Actually had been looking at the Morel rollers he runs as well.

Thank to all here.

 

[Charger 770]

"My block does not have bushed lifter bores, so I do want to check the oil passages and confirm the base circle requirements, as INTMD8 has brought to my attention. "

Just info for ya, mine does'nt either (MP siamesed bore, Hemi block) and it's OK with Isky Red zone EZ MAX bushed roller lifters. Not sure on the BAM or Crower lifters.

I know of another 572 with this cam in an early KB alum block that does NOT have pressuried oil to the lifters just splash. Been on the road for years and is FAST at the track. Needle roller Isky Red Zone lifters were checked over the years at least 3 times and he was told by Isky to put them back in the engine. Testament to the lobe design on this cam.

Note the further up post with the lobe profiles (4016S/4032S) and correlate it to the cam card lobes used. Both intake and exh lobes are under 200 deg @ .200" lift.

With locked out timing it idles great on the street and is'nt obnoxious. Hope this helps.