looking to hit up my truck with bigger cam, pushrods, lifters, entire valvetrain...
but i need to know my max lift without interference.
help?

 

Are you going to do anything with the heads also or just the cam?

 

Stock valve lift for a 5.2 is .432 inch.
Stock valve lift for a 5.9 is .410 inch

My 360 camshaft is ground .462/.470 and I used 1.6 roller rockers. Also had to have the valve guides cut down and better valve springs installed to prevent coil bind. You also need some extra clearance to allow for any float that might occur during high RPM's. I think I remember hearing the minimum was .1000

This is the calculation as it was explained to me. if I'm wrong I hope somebody else can correct it.

For my 5.9
.462 * 1.6 = ,7392 + .1000 = .8392 required travel of valve
.470 * 1.6 = ,7520 + .1000 = .8520 required travel of valve.

My original heads did not have the guides cut down correctly and I broke 1 valve, 1 rocker arm, and bent half the pushrods. Since that happened, Ibelieve the original head work was for a stock engine when it should have been done for my performance engine. My new replacement heads were correctly machined.

Good luck and make sure that you get it right.

 

http://www.carcraft.com/howto/116_0401_318/index.html

it is well worth reading the whole thing carefully,
but especially this quote:

Delving deeper into the works, we found the camshaft was primarily determined by the heads. Magnum heads offer an excellent intake/ exhaust-flow ratio, which favor a single-pattern cam. The stock valvetrain is cheap, but highly effective. It's also nonadjustable, so we went with a hydraulic grind. Retainer-to-guide clearance becomes a limit at 0.525-inch lift, so we opted for a Comp 280H, coincidentally part of their "Magnum" line of camshafts. With a stock 1.6 rocker ratio, gross lift worked out to 0.515 inch, and duration at 0.050-inch tappet lift was a generous but not outrageous 230 degrees. Lobe separation is 110 degrees, promising a drawn-out torque curve for prolonged high-rpm pull. The standard Comp 822 lifters allow for valvetrain oiling.
end quote

 

Appreciate the extra info. like I said, I may have heard or written down the wrong info for my calculation. But this info came right from one of my Mopar Magnum books:
Stock valve lift for a 5.2 is .432 inch.
Stock valve lift for a 5.9 is .410 inch

Hopefully somebody that knows cam/valve/rocker arm geometry can set us right on how to calculate total lift based on rocker arm ratios.

XXL1500 I would definitely look further into HankL's post for additional info.

 

I would say that .462/.470 is your gross valve lift using either 1.5's or 1.6's. If it were say 1.5's:

.462/1.5= .308 wich is your lobe lift.

Then if you went with 1.6's, you take your lobe lift and multiply it by your rockerratio to get you gross valve lift:

.308 x 1.6 = .493

Your cam card should give you the lobe lift and if the grind is vehicle specific, it should give you the gross lift using the stock rocker ratio.

Also, if you are doing the cam, pushrods, and lifter,it may save you alot of headaches to switch toadjustable rockers. This way you can make sure you get the preload on the lifters right.You can either measure for pushrod length, or get3 or 4 sets and return the ones you don't use. If you go with Krc or Comp (same difference) I would get 6.850, 6.900, and 6.950. If the cam is a new core then pushrod length will end up close to stock wich is ~ 6.900 (unless you are doing head work).

 

so it looks like it is gonna be a .515 right?
that is the maximum size lift in the cam i chose to buy that will go in without any interference
to hitting anything....
should i stay with hydrualic?

what im looking for is the LOPIEST idle i can get out of my engine
i will prob be converting to the M1 soon also, and maybe some heads down the road
but i will just run stock heads till they crack and leak and buy the iron heads
once that happens

.515 correct?

 

It's not really the lift as much as lobe seperatin and durationthat will make it lope at idle. Less than 112* is not really considered computer friendly, but you can make 110* run, and it will give you a lopy idle. The Krc206x is ground110* and has a .480/.512 lift w/ 1.6's. If you went to 1.7's it would give you .510/.544 w/a little more duration.Remember, if your going to try to keep the truck streetable, the biggest cam you can get is not always the best. You want to try to keep some bottom end. Call Marty at Krc or Comp cams. If you get your cam from comp, you will save a few bucks, but you will not get the DC specific support that goes along w/ theKrc cam. Marty may tell you that your better off getting theintake/heads/exhaust before you worry about a cam. If he does, I would listen. If you have a big air moving cam sitting between the stock manifolds (int/exh) it may cause you headaches. If you wanted some extra grunt for the time being, you could go with adjustable 1.7 roller rockers, and still use them when you get your cam.

Unless it's going to be a track only truck, I would definitely stay hydraulic roller. You don't have to worry about the tedious break-in crap, and you will not have to hunt down special oil to make it last.