I have acquired a nice low mile 1974 4 speed cuda. The engine runs great and is a early 1977 ported w2 Head 360. I know nothing about the internals so I checked lift at the valve and it’s .495 and 180 cranking compression.
With .028 lash. I’m trying to guess the actual cam lift without tearing the motor down.
I also want to spec a new solid cam with more lift and possibly duration.
So with a 1.5 rocker how much do I lose at the valve with the angle??
I am also gonna need help speccing a cam. This will be street strip 4.10 gear And the rest of the car will be original.

I would pull the rocker arm assembly and use a dial indicator with enough preload ( to try and keep the pushrod halfway straight from opening until closing)to measure the lift at the cup of the pushrod to see what it has and hope it is close to the lobe lift, once you have that you can do the math on what you measured at the retainer for net lift and go from there Good luck
that way or get a real long extension for the dial indictor stem and measure off of the lifters, measure one intake and one exhaust to get the gross lift for both

When i swapped my cam in my old 340 (.557 SFT mopar) after degree wheel, and dial indicator was set on the retainer, All i could get was .519 at the reatianer. i was running 1.5 harland sharps. Hope this helps! the W-2 pushrod angle, push the 59* lifter angle, really doesnt help with anything. you can get better angles and lift if you run a solid roller with a .180 offset cup on the intake lifter. also a .550 offet intake rocker and 5/16" thickness pushrod will clear ith above combo. this will put the pushrod slighty more inline.

If it is an econo head and has saddles for the shafts you can bet about everything you have the geometry isn't correct.

If the heads have blocks for the shafts, I'd still verify geometry.

Like cab said, eliminate the rockers and measure lift from the lobe and do the math.

If the geometry is correct, you shouldn't lose more than .010 lift with that little cam.

The heads are the race style shafts and part # ends with 810. The have ductile rockers.
I don’t plan to go through all of the trouble to find out the actual lobe lift
Until I take the engine apart. I do appreciate cabs advice though.
I really just want a general idea so that when I spec a new cam,
I know how much lobe lift to go with.

Put a dial indicator on the retainer, measure. Takes a mere minutes. If you want it to run good it needs checked. I always try to make our stuff excel, this is all part of it. Just a guess if not. After messing with the w series of heads and 59 degree stuff for 22 ish yrs, some stuff will shock you when checked.

I tried to measure the lift on my 340 cam at the spring retainer and was getting varying results and gave up. Seemed like the lifter was bleeding down on me. In the end, what cam is in there is immaterial if you are looking to optimize the combo. Give the cam grinder your combo including head type and flow and they will give you a grind recommendation. I recently had visions of slapping in a cam with .510 lift and .240/.246 @ .050 but after talking to Crower, my combination and use case would max out with about a .490 lift 225 duration cam. The big cam would've probably sounded good but would drive like crap on the street.

Jim Dowel at Racer Brown grinds some nice cams. My Duster ran 9.80’s with his .520 lift cam on pump gas in my Duster with a set on W2 heads that I did a mild port job to on my 408.

Exactly.
Don’t get too hung up on what it “should” be.

Realize it is what it is, and build accordingly.

Another waste of my time.
Yes, "do the math".
What math, exactly?

Ryan, I did measure at the retainer and it was .495+.028 for the lash. My issue is that I don’t know how much lift I lose with the angles. And when I get a new cam I would like around .580-600 at the valve.
So I’m trying h to figure out do I order a .640 lift cam to get that? Etc.

Ryan can you pm me your number?

You need to deal with a competent cam grinder to figure that out.

My last cam deal was a Racer Brown deal and I wanted to net .600 at the valve. The gross lift in .620 and the lash is .014/.016 hot and I net about .602ish.

I also made sure I used a pushrod everyone thought was overkill and would have went bigger yet bout didn't have the room.

I also used a B3 geometry correction kit. Between the cam grinder knowing what he's doing, stiff pushrods and getting the geometry correct will reduce lift losses to almost nil turning the engine by hand. What happens dynamically is a whole different discussion.


Also, I would never lash that cam at .028 for any reason. There is no reason for it. The lash ramp is a mile long. All that loose lash does is beat up on parts.

So I wouldn't suggest that you try and add deflection numbers to your gross lift. Get everything else right and you'll be close.

Also, you always need to check and verify what you are doing with the spring you are going to run. All rockers flex. All of them. If the guy designing the rocker had his crap together, he added a bit of ratio to the rocker so the ratio is correct when loaded.

As an example, I was testing rockers back in probably 1996ish and I had Crane golds, Chrysler ductile and Norris stainless rockers (the very best rocker out there IMHO). The Norris were 1.6 ratio and the others were 1.5 ratio. With checker springs, the Chrysler rocker was about (going off memory here but I'm close) 1.55 while the Cranes were 1.58 and the Norris came in at 1.66 so all of them were higher than nominal ratios.

With load, the Norris rockers actually came it at 1.61 while the Chrysler's held their own at 1.49-1.5ish and the Cranes were about as good as the Chrysler rockers.


The point is, check it loaded and make sure the geometry is a good as it can possibly be.


Edit: and don't forget overkill on the rockers. When I do my next W-2 headed deal, I will be using, at the minimum a 3/8-716 single taper pushrod, with a .120 wall. Who knows...I may say piss on it and order 3/8-7/16 double taper pushrods to get everyone excited.


FWIW, when I was doing the big roller stuff, I was using double taper pushrods. At the time, everyone said I was insane. But the results showed otherwise. The adjusters stopped coming loose. The valve train became much more noisy. And the car picked up a .1 so it was worth it.

You can't get a pushrod too big or too heavy. Especially when you are dealing with the angles we deal with running the 59* stuff.