New Automobile!

[Prince Valiant]

the stock rockers are 1.5:1 correct?i like shaft mount design. i am planning to do roller lifter conversion also

Stock rockers are supposed to be 1.5:1 ratio...but in reality work out to 1.42-1.44 on average.

The stock rockers actually work quite well on older designed cams like the mopar performance ones, most of the magnum cams by comp cams, etc....but start getting into the newer "high velocity" or aggressive ramp cams such as the comp XE series, or hughes, the larger cams may present problems as a push-rod is likely to push through the stock stamped rockers. Upgrading them to tougher ones is a cinch, and is inexpensive (like 30 bucks for 16 new ones) with thicker stampings...but the ratio remains poor.

Crane, comp, et al all have nice upgrades...normally 1.5's yeild a nice power increase themselves. Some have trouble going to 1.6's just because they are lazy and don't want to correctly measure the needed push-rod length to keep the geometry correct and just adjust to suit using the adjustable rockers themselves...either way, it's a win, just make sure you take the time to measure everything correctly.

That's another mopar advantage...the lifter base radius is a large advantage for mopars. With larger lifter bases than either ford or chevy, you can get a more aggressive "ramp" with regards to the camshaft...IE, for a given duration, you can have more lift dialed into the cam, without the edge of the lifter digging into the cam itself. Comp XE even has a special sub-sub line (since the XE is a sub-line of cams itself) that feature patterns taking full advantage of the mopar liftter....other cams include Hughes Engines, and Racer Brown cams. If you go to roller cams, the advantage becomes effectively nill.

If you are going to swap to a roller rocker set-up, I'd strongly recommend going with a mechanical flat-tappet cam from either hughes or racer brown. It'll give you a ton of power, ability to rev, great sound, and still be quite driveable vs a comperable hyd cam of the same size, and make more power than the hyd cam too.

And yes...shaft mounted RULES. VERY EASY to work with...

[MurphysLaw88GT]

the lifter diameter.....is that why people ***** about "chevy lobes" on chrysler cams, because of the difference

[MurphysLaw88GT]

a nostalgia s/s driver/engine builder i know (steve hagberg) recomends racer brown cams, and sold my freind todd a max wedge with a racer brown cam (13.5:1 yikes!!)

[MurphysLaw88GT]

you can run steeper ramps with roller i thought

[Prince Valiant]

the lifter diameter.....is that why people ***** about "chevy lobes" on chrysler cams, because of the difference

Yep...most cams are just a copy of the cams that are made for chevy's, just using a mopar blank.

So if you look down the mopar line of cams in a comp catalog, you'll see that the chevy has the same cam lift vs duration as the mopar, even in the "XE" series that supposed to push the limits for the cam ramps...which it does, for a chevy. It's not that these are bad cams...the cam I've got now is a "chevy" cam really...but it COULD be better.

Everyday of the week the cam with more lift, despite same duration, makes more power.

Hell, even if I had more lift, and slightly less duration, I'd have an engine that made more power, yet idles more easily with more vacuum and less hassle...that's why many went to roller cams.

Comp did expand the XE lines to use "mopar" lobes, plus the other aformentioned maker's make exclusively "mopar" cams. Ironically, Mopar Performance sells essentially "chevy" cams...although they are better than the typical comp/crane/eddy cams of years past. Most of the inexpensive cams made now are 30-40 years old as far as design. I'd strongly recomend hughes cams...they may be 100-150 bucks more...but they make SERIOUS power with no loss of driveability.

[Prince Valiant]

you can run steeper ramps with roller i thought

yep...but a mechanical lifter is a) cheaper, b) lighter, c) will allow the valvetrain to last longer on the street (springs, retainers, rockers due to the less valvetrain weight and subsequent heavier springs needed) and d) Many argue that a mechanical is just as effective at making power because the initial ramp is more aggresive on a mechanical flat-tappet cam...IE, for the first .020 lift, the flat-tappet cam is raising faster than the roller, which due to it's weight, etc comes off a little slower.

But, either way, you can't really lose.

[MurphysLaw88GT]

the cam is where i do NOT want to cheap out, as it plays too heavily in performance/driveability to want to save a few bucks. dont want regrets, as that means spending more $$ to get the rite one later

[Prince Valiant]

the cam is where i do NOT want to cheap out, as it plays too heavily in performance/driveability to want to save a few bucks. dont want regrets, as that means spending more $$ to get the rite one later

Well, actually the one place where you don't want to cheap out on is the heads...if anything allocate the most you can there IF you are planning on making over 400hp.

I'm a big fan of the wild heads, mild cam school of thought...I'd rather drive a 450hp 383 with mildly ported eddy heads and a milder cam than a 450hp 383 with stock-ish heads and a wild cam...either of which is feasible as that's about what the stock large block heads can support in stock form (actually around 480-500 depending on the casting)

It's just that the better heads, milder cam engine will idle better, make more vacuum, be easier to tune, have a broader power band, get better gas mileage, feel faster, and will just be a generally better engine


Beyond 450hp though, it becomes seriously diminiishing returns on a non-ported, stock headed mopar as the cam needs to be really big.

[MurphysLaw88GT]

i have the 906's with the motor, maybe i mite pickup a 34'000 mi 67 440hp with the closed chamber 915's

[MurphysLaw88GT]

btw, how u wipe the lobes on your hughes cam?

[Prince Valiant]

Bad oil...most of the modern oils lack enough zinc for high pressure lubrication that is needed for older engines with flat-tappet cams. The zinc content is lowered to lengthen the life of catalytic converters and O2 sensors that use platinum, and don't need as much zinc since they use low friction roller lifters/rockers.

So while I used the proper pre-lube, followed proper procedures, etc, I still suffered failure within 50 miles of initial start-up. This is actaully becoming a more comon problem in the last 3-4 years, with numerous articles/threads questioning the common failure of cams.

Now I use "racing" formulated oils, or oil made for diesel engines (rotella, etc) as they have the zinc content needed for older engines. When you start up an engine with a newly installed cam, not only should you have the proper pre-lube and proper oil, but you should also run a can of GM EOS in there as well.

I'd be cautious on 915 heads...the problem is that they need to be MADE into great heads. They generally have small intake, and small exhaust valves, and aren't great for flow. By the time you've have a machine shop do the requisite work to get them to flow like a good set of 906's, you've spent almost enough money to buy brand new closed chamber eddy's that blow stock 906's out of the water, and make stock 915's look like heads for a flat-head ford.

Closed chambers are great...but I'd rather have great flowing open chambered 906's vs poor flowing, higher compression closed chambered 915's. Flow is where the power is at.

Of course, the eddy's make the best of both worlds with less weight to boot (total of 50lbs).

[MurphysLaw88GT]

the reason i wanted roller is because someone (possibly the prince himself) posted a link showing modern oils dont have the proper amount of zinc and other stuff to be compatible with flat tappet. i would like to avoid wiping the lobes out!!!and less friction to boot. my freind has got a 69 hemi roadrunner, to avoid fvcking the lobes...what kind of oils should he run, i belive it has some kind of sinthetic in it.rather safe than sorry, because hemis have a more agressive spring i think

[Prince Valiant]

Well, most the problems are occuring on initial fire-up on a freshly rebuilt engine, or one with a brand new cam, when you wouldn't be using synthetic anyways, so use of the "racing" or "diesel" oils is what I'd use. Generally, you can find an oil supplement that will add zinc at many parts store, but I'm not positive...GM EOS should be fine...but adding some to synthetic, or just adding a quart of rotella with another 5 of synthetic is fine too. Generally AMS or Royal Purple synthetic oils have more than enough zinc in their synthetic...

[MurphysLaw88GT]

once i know what is going on with the motor build (financially), i will have better direction perhaps. but this i KNOW....i want stock APPERARING, but with more bite. i love the sleeper look

[Prince Valiant]

To make is "stock appearing" is fairly easy enough...because it's "how stock do you want it to appear" For some, they'll accept headers and still consider it "stock appearing". Hell, some will accept eddy heads, performer rpm intake, holley DP carb, just as long as it's tucked neatly under the correct air cleaner and the engine is painted correctly with the correct engine accessories and a stockish looking ignition and fuel lines, etc....and then there are some that "stock appearing" essentially means that everything that can be viewed or touch must essentially be stock...so to get extra power one needs to have extrude honed intake and exhaust manifolds, highly modded stock carb, trick roller camshafts w/ switched firing orders, that sound stock until you get on it, very ported heads, etc...

[68RR440]

btw, somebody was using an old unrestored 4 speed Hemi GTX as a tow rig, i got some shots with the trailer HOOKED UP!!!!!had old montana plates. this place was rediculus

This is what came off the trailer ...

[MurphysLaw88GT]

^^^Did you see the photobucket account!!!it works haha. that particular hemi barracuda has no engine currently, he said it sat since 1981?....i know the guy, does AWESOME bodywork!!!we had to deliver 5 oilpans to that guy. didnt see what he arrived in LOL

[purpl72olds]

Sorry prince, i was taking a guess on that motor combo earlier, I knew it was either a 400 or 440 crank cause the engine i seen was a pieced together motor with that made good power for the parts that were in it.

[MurphysLaw88GT]

that challenger sounds awesome^^^^

[MurphysLaw88GT]

Took the carb off today