Going to need at least the following: Engine size, intended RPM range, rear gear, cylinder heads, carb size, intake type, exhaust (headers, etc.). 

In general you'll want a wider LSA to reduce lope at idle.  I would not look at anything tighter than 112 degrees.  If you run EFI it will be more like 114. 

I have a 351w in my '66 and have changed to a Comp Cams retrofit roller.
Part # 35-421-8
Grind # XR270RF-HR10

Specs:
Lift - .513 both I&E
0.050 Duration - 218I - 224E
LSA - 110

Rear end - 3.00
Cylinder heads - Ported DO0E 351W iron
Trans - wide ratio T5
Fitech FI
Exhaust - Heddman 2.50 shorties
Max RPM - 5000

So My engine, tho smaller than yours, is similar in usage.  I can pull from 1200- 5000 where I run out of air.  Therefore, with your 416 you could easily go to something closer to 230 deg.  Your choice of having one lobe config or two.  the .513 lift allows me to continue to use stock valve springs.  Sound burbles, but is not too loud.  And I do get a lot of looks when I drive by people.  I do a little canyon carving and like to punch it on fwy on ramps.  That is the limit of my need.  What is yours?  You need to determine that.

LSA is lobe separation angle.  The angle between the top of the intake and exhaust lobes.  Take TKO's advice on this.

Finding the proper cam can take a lot of time because you can specify separately, which lobe configuration to go with on the intake and exhaust valves.  Lobe designs come in something like 2 deg increments, so there are a myriad of combinations.  As you go up in lobe config the power changes incrementally, so, how far is too far?

  The cam mfg's have web sites to help and those here have their preferences that they are quite willing to share and recommend.  I spent several months with my search.

Wow, I was thinking of maybe doing this without pulling the engine or the heads. From what I can tell, and I am guessing, the current cam has a .472 lift and the roller cams have a .5?? lift. I guess that means my pistons will need to be cut some more for valve clearance.

Why not get a roller with the same specs you have now (I think Edelbrock has a roller with those specs OR......get a roller cam custom ground with the same specs as you have now).
I used Delta Cams  butt Howards grind special order cams too. As does Comp Cam.
They grind all kinds of custom ordered cam from  "Big Boy/snot slanging/take no prisoner cams"..... or Lil Girl grinds like what you're looking for.
Price is comparable to shelf grinds(in some cases cheaper)

Duration    Intake  204@050
               Exhaust 214@050

Lift             Intake 4.48                                                            This is what you have NOW
              Exhaust  4.72                                                            I would at least  get 4.72 intake and exhaust lift you shouldn't
                                                                                                need to change you pistons because you don't have issues now
LSA          112* (advanced 5*  center line 107*)

IF you keep the same LSA and  around the same Duration you will have smooth idle and good vacuum. 
Too much duration with LSA  around 112* will /could give you pinging issues at low speed you never said what your CR was.
6sal6
PS..........I'm thinking the heads will need to come off

Last edited by 6sally6 (10/01/2019 6:43 PM)

HudginJ3 wrote:

Wow, I was thinking of maybe doing this without pulling the engine or the heads. From what I can tell, and I am guessing, the current cam has a .472 lift and the roller cams have a .5?? lift. I guess that means my pistons will need to be cut some more for valve clearance.

How are you going to rebalance the crankshaft without doing a complete engine teardown? There's no other way that I know of to balance a crank.
And what's the problem with ZDDP? There are lots of oils out there that have plenty of ZDDP in them without having to add it.

ZDDP issues aside, I will never again build an engine without a roller cam, unless it was a 100% correct restoration (unlikely I'll ever undertake one of those again).  Wear is only one reason why manufacturers started using roller cams.  To me, the additional power under the curve is a major advantage that can really be felt on the street.  Whereas the only drawback is price.  This is why I run roller cams in everything. 

I admit I don't know everything about engine balance, but what I'm hearing doesn't seem to make any sense.  Crankshafts are balanced based on a set bob weight, which is the mass of the piston, rings, rod, and bearings.  Then they figure the effect of that weight using a program like Spin Balance that takes into account angular momentum.  I don't see how the crank can be out of balance if the bob weight hasn't changed.  Sounds to me like they just couldn't get the flywheel balance right...

I think this ends with you chasing your tail.  The flywheel change didn't work, so the crank comes out, goes back in, and it still isn't right.  Unless I'm missing something what's so special about the balance on this engine?  Typically you are going to be 28 or 50 oz imbalance and you just bolt on the right flywheel.  I run an off the shelf 28 oz. flywheel on my 289 without any issue.

The crank was a promotion deal that Speed-O-Motive did in 2004. I came not balanced with pistons rings and connecting rods. The machine shop said they could balance it. They drilled holes in it and wielded heavy metal into it. They finished it off by welding more weight onto the flywheel. When I put in the T5 they said they could match the new flywheel to the old one. I now have two images in my rear view mirror so something is out of whack. I guess if this doesn't work I'll put an original crank back in whilst chasing said tail.

The  crankshaft is a aftermarket manufactured by Speed O Motive to achieve the 416 cubic inch stroke. They did not balance it during manufacture so I had to balance it. They balanced and weighed the connecting rods and pistons. I had to supply the dampener and flywheel. It was all re-balanced re-checked and balanced in 2004 adding Mallory to the crank and then to the flex plate. The machine shop gave me the balance results card and kept it in their records also. I asked him if they could match the fly wheel with the flex plate he said possibly but no guarantees. When we discussed that it didn’t work he told me he needs just the crankshaft, fly wheel, and dampener. He needs to add more weight to the original weight. The machine shop is Wells Racing. I have been using him since 1983. His engines have been pretty successful. I’ve never had any problems with any of his other work that he done for me.

"Always room for one more"(comment)!
With engines that are externally balanced like most SBF's "they" refer to the crankshaft as being and 'unbalanced' crank.  Meaning I guess ........crank unbalanced BUTT with the right external balance of flywheel and dampener it will then become 'balanced.
Now if they are building an engine that is internally balanced(like a lot of race engines) then they add mallory(heavy metal) and remove weight were needed.
I would think........going from a flex plate(I balanced) to a flywheel (I balanced) I SHOULD be able to get it right WITHOUT re-doing the crankshaft!!
Don't know'em butt.........."Something--is-dead-in-Denmark" huh Hakan?!!
6sal6

My guess is you have some bastard balance deal going on.  Stroker kits often come unbalanced because it adds cost for the supplier.  Typically a small Ford is going to use some measure of imbalance.  Now, what they can do is balance it at 28oz or 50oz imbalance, whatever is easiest to achieve, get it to neutral balance, or end up with some oddball balance that was easy (like 33.8oz imbalance, etc.).  I'm thinking you got the later.  Personally I always shoot for neutral balance, which was always easy to achieve on a SBC, but costly and simply not worth it on a SBF.  My 331 balanced using a 28oz. imbalance.  That way if I ever need to swap balancers or flywheels I can just use an off the shelf part. 

Balancing is an interesting subject.  I knew the guy who wrote the Spin Balance program, and I talked to him about it.  He said that an engine is never really perfectly balanced except in a very narrow RPM window, which when you think about it makes sense.  The faster the engine spins the heavier the piston/ring/rod assembly gets due to the forces acting on them.  The trick he said was to achieve the best balance for the operating range.  An engine that was going to spin NASCAR engine speeds would be balanced differently than a street/strip engine for example. 

351's come with a 28oz balance.  The two ?'s are done only if you need to change to a 50oz balance.  You should not have to do this.

Its a stroker, so the factory balance of a 351 may not apply.  It has to be balanced based on the bob weight of the rods/pistons/rings its using, which, especially in a performance engine, are going to be different than stock for a variety of reasons.  Its common for strokers to use non stock rod lengths for example.  The piston design is often varied as well based on where the pin hole needs to be for proper compression height.  Heavier duty aftermarket parts are often literally heavier as well.  4340 rods are going to be heavier than stock rods, etc.

Now, there's a lot they can do to make it easier to balance.  Pistons can often have material removed from non critical areas to lighten them up and reduce the bob weight.  They can sometimes change the orientation of the counterweights on the crank to improve its inherent balance relative to the bob weight without having to actually add any material to the counterweights.  This kind of stuff isn't typical for budget stroker kits though. 

My guess is that the setup was designed to balance with a 50 oz. imbalance like a 5.0.  Then I'm betting that the shop found this was more difficult than say a 43oz. imbalance and set it up for that, modifying the balancer and flywheel/flexplate to that balance.  This is why you're having issues.  If they had just set it up for a 50oz. imbalance you'd be able to use off the shelf parts.  Now deviating from the parts they balanced with the engine is causing problems because they are modified parts.