416 Stroker Kits - Scat or Eagle

[erik70rt]

As I continue to gather parts together for my 416 stroker build, it's time to start looking at the different rotating assemblies.  When I build my last one, I went with an Eagle kit on the recommendation from the guy who was doing my machining work.  He thought Scat was absolute junk.  But in the posts here, I see several people prefer the Scat assemblies.

So I will put this post up as our chance to debate which assembly everyone prefers and why they prefer it.  Which kits do you like?  Forged crank/pistons vs cast?  H beams or I beams?  Combinations of forged/cast?

Ready.........go!

[gzig5]

I don't have any direct experience yet, but everything I've read puts Scat above Eagle.  There are a lot of posts on Moparts and FABO forums on this topic.  Most say that the Scat cast crank is good up to 600hp, but the Eagle cast crank is junk.   Molnar is also well regarded.  That is all I can contribute, but I'll be going with a Molnar or Scat.   I don't think my build will be wild enough to require a forged crank but for a couple hundred dollars it is cheap insurance and better for resale in the unlikely event I would part ways with it. 

The other topic that comes up is balancing.  Using the vendor supplied balance option or having your engine builder do it.  I don't have a dog in that fight yet.

[Chryco Psycho]

Buy the best parts you can , forged crank , light I beam rods & forged pistons why cut corners for a few $100

[7212Mopar]

My engine builder was going to use a Scat cast crank with forged pistons, good for 500 HP build. I told him to go with Scat's forged crank and pistons for just a few hundred dollars more. I think Scats has hypereutectic pistons with their standard cast crank package and both their cast and forged cranks are internal balanced. But you should check that to be sure. I prefer internally balanced engine so I don't have to deal with the external balanced flexplate or flywheel and harmonic balancer.

[Oldschool]

I have used both Scat and Eagle forged crankshafts in both BB Mopars and SB Mopars. I have used magna-fluxed, and polished and balanced factory cranks too. I have always sent them to the machinist before I do anything else and have the rotating assembly balanced. I have never had an issue with any of them. My current engine is running Eagle stuff and so far, no issues. I think that you can get good and bad in any brand. You probably won't go wrong with either of the choices.....

[autoxcuda]

I've been running the Scat cast crank, forged piston, I beam rods, balanced assembly for 8 years now.

About 20K miles

About 450HP build +/- 25HP.

I take it to Willow Springs Road course once a year and flog on it to about 6K rpm.

I cruise at 75mph at about 3600-3700 rpm down the freeway.

Been flawless for me. Smooth and engine balance is fine. Scat balances on site in Redondo Beach, CA

I've been to their facility. I've talked with the same people at SEMA. It's not just a drop ship kinda deal.

A friend and myself built it. We checked the parts meticulously before install and mock ups with correct tools. Items were spot on.

[erik70rt]

I agree about spending the extra $$ and go forged. 

How about thoughts on flat shaped pistons vs dish pistons?

[dave73]

Are you building your motor yourself or having someone else do it? I went down this road as well, questioning what was best and all. I ultimately deferred to what my engine builder recommended, what he prefers to use since that's what he'd stand behind. I didn't want to be in the situation where I bought parts he did not want to use, then god forbid something went wrong, he said "told you so". I got a great motor but like anything, now I want more and more power ha!

[gzig5]

I agree about spending the extra $$ and go forged. 

How about thoughts on flat shaped pistons vs dish pistons?

Depends on your heads and cam I think, and what you want for final compression ratio.  I think most of the aftermarket 63-65cc aluminum heads play well with flat tops at zero deck.  With the right gasket you get good quench and it will run on 91 octane at 10 - 10.5:1.  If you want/need to run on 87 swill you may be better off with dished pistons to knock it down around 9:1.  I plan on going with flat tops and getting as much squeeze as 93 premium will allow me to run.

[erik70rt]

I usually run the flat tops and build it to run on 93 octane. 

[kawahonda]

Forged doesn't automatically mean better.

[1 Wild R/T]

Forged doesn't automatically mean better.

Yes it does.... It may be over kill for an application but it's better...  Forgings are much tougher than castings... Forgings bend, castings break....

Some will tout the weight savings of cast & while thats true well designed forged parts weight so much less than OE that it's a moot point besides the reason the forging weights more is the density of the material....

[Chryco Psycho]

 

[RUNCHARGER]

I always go forged unless the engine is totally stock. It's always nice to know you can throw a better set of heads and cam in or a nitrous kit on if you want to in the future.

[chargerdon]

My engine builder was going to use a Scat cast crank with forged pistons, good for 500 HP build. I told him to go with Scat's forged crank and pistons for just a few hundred dollars more. I think Scats has hypereutectic pistons with their standard cast crank package and both their cast and forged cranks are internal balanced. But you should check that to be sure. I prefer internally balanced engine so I don't have to deal with the external balanced flexplate or flywheel and harmonic balancer.

Internally balanced yes...but one of Scats stroker kits comes with "Balanced by Scat" for extra $100...vs paying a machinist $200-300 for him to balance it.   Now does the machinist do a better job than trusting the mfg?