1.7 rockers with 380HP Cam

[72DMag]

Can 1.7 rockers be installed on magnum heads with the 380 hp camshaft or will retainer to seals hit? Stock lift for the cam with 1.6 rockers is about .501 on intake and .513 on exhaust.

Sounds like max lift that's safe for valve retainer to valve seal clearance is .525 lift correct? So even with the bigger mopar springs good for .600 lift p4976062 and the 2.2L retainers its not possible to add the 1.7 rockers? Lift with the 1.7 would give me about 532 on intake and 545 on exhaust.

 

[rumblefish360]

I’m not positive on this, but IIRC, the Hughes engines have a trick retainer they found to use on Magnum heads that allow that lift.

Edit, went hunting for you between period 2/3 of the Stanley Cup.
(Tampa is getting hammered.)
The description at the BOTTOM of the page says .550 lift.
Up top it said .620 coil bind.
https://www.hughesengines.com/Index...bnVt&level1=VmFsdmUgU3ByaW5ncw==&partid=30450

 

[Bobzilla]

In the thread below I listed the measurements I got a while back when checking retainer to guide clearance on a stock 5.9 lower end, stock Magnum heads, but using the Hughes retainers, springs, and locks and a Hughes cam. Check out post number 12.

Oil consumption and ticking after cam swap?

 

[RustyRatRod]

@MOPAROFFICIAL can probably tell you.

 

[72DMag]

@rumblefish360 @Bobzilla @RustyRatRod Thanks fellas appreciate the info and since the Penguins aren't in the stanley cup final again SMH. I'll do some research on those hughes retainers. Didn't want to upgrade to +.100 valves and beehive springs just for a step up in rockers to give the truck a little more power.

 

[MOPAROFFICIAL]

That's something theoretically will work. But you should none the less check.
It's still a 59 degree lifter angle so some will be lost.
Calculate the extra, set max and put the rocker down with a dial indicator on it to see how much room is left. If you like to Tinker, it should be fun

 

[RustyRatRod]

If you like to Tinker, it should be fun

That's what she said.

 

[Bobzilla]

@rumblefish360 @Bobzilla @RustyRatRod Thanks fellas appreciate the info and since the Penguins aren't in the stanley cup final again SMH. I'll do some research on those hughes retainers. Didn't want to upgrade to +.100 valves and beehive springs just for a step up in rockers to give the truck a little more power.

I think the longer valves just cause rocker geometry problems. Easiest option is remove the heads and cut down the guides or just get a different camshaft.

 

[273]

Your probably better off with another cam, you don't always gain power going with higher ratio especially with a cam not designed with them in mind. But saying that the 380 cam seem like it would have slow ramps so it could work.

 

[rumblefish360]

It’s more of the cylinder head not being able to flow more air with the higher lift than the cam itself.

Also, with the cam, 273 does have a good point about the cam. Thanks don’t know how that 360/380 cam is ground. How aggressive are the lobes? Just because it is a kid lift cam doesn’t mean the lobes are lame! While the being think there a “Race Lobe” cam since bracket racers did well with them, a spec ground cam, can certainly kick some ***.

 

[72DMag]

True I don't really know the exact details regarding how mopar did the ramp rate on the lobes of the cam. However, I do disagree about not gaining power from a higher ratio rocker. You could argue I won't gain as much compared to another cam, but I can't see how a higher ratio rocker does not at the very least gain a handful of HP somewhere in the powerband.

A higher ratio rocker does 3 things, 1. increase valve lift, 2. increases the speed of the valve opening and closing 3. adds some duration. Given that, a higher ratio rocker arm will always give you something depending on the application.