Anybody know the limits of cast stroker cranks?

If you'll Use a stud girdle & pour the lower part of the block it should hold up fine.

 

The only downside to Forged bottom end is that WHEN it lets go, it will be about twice as much money to fix it. Other than that, yeah, I'm told the forged cranks are much stronger. In my case, I guess it doesn't matter when the block is the weak point. Guess I could upgrade to an aftermarket block...but jeez the price of a Dart block is more than what I have invested in the entire engine minus heads!

 

Anybody know the limits of cast stroker cranks?

Yes when you hear bad noises coming from under the hood and see an oil slick.

 

Where do you shift? How high have you ever spun it? I am leaning towards a cast crank again.

I have been doing alot of reading and it seems cast cranks are good for aroung 600-700hp. I dont plan on making that much. I can save alot of dough by going with a cast crank and hyper pistons. I have also reevaluated the possibility of boost in the future and decided against it on this engine. The main reason is compression. I want to run around 10.5-1 or higher, but that wont be too boost friendly. Also, hyper pistons make for a tighter fit and are quieter with less slap as a result. Right now Im trying to decide between scat and eagle as they can be had for the same price.

 

I like both Scat and Eagle. Scat makes a killer cast crank (9000 series) that won't set you back too much. I think I got mine on clearance from a popular website for around $200, IIRC. Same for the Eagle, except it was about $250 with shipping.

How high have I spun it? In the burnout box, I've seen the high side of 8K before, unintentionally. I have a limiter and have a 8K chip in it...but sometimes it comes up so quick that by the time the limiter catches it, it's gone past it. When I first put the motor together, I was breaking it in (the hard way of course) at the track and I do remember seeing 8300 under full power once on one of the first passes I made with the 415. Don't remember how I got it up that high, but it lived through it, so I ain't afraid of it.

BTW, if you're leaning toward Hyper pistons....lean the other way. I personally am not a fan of them. If the timing is too fast, the top ring land will break out. Too lean=same thing. We've broken at least 2 or maybe 3 of them in the same engine. Yes, you can run them tighter yes they are "ok" for nitrous/blower/turbo and yes they're very heavy. I think the set we have in the Mustang cost something like $270 for the set (I think they're KB116's...dome...around 11.5:1 compression in a 302) and they weigh around 650 grams, IIRC. The pistons in my 415 are 405 grams, but they are forged and much shorter....flat tops. The ones in the 415 were only around $440 IIRC, WITH rings (they came with the pistons). Like I said, nothing really high $$$ about the thing. It just works better than I expected it to. I just wanted something that ran as well as my old 14.2:1 357w that grenaded and it does just that....and then some. The 415 uses a Scat 9000 crank, FYI. Eagle H beam rods and Mahle pistons. A home-brewed combination that didn't set me back as much as some have spent on a similar combo. If that wasn't enough, the heads are out of the box Victor Jrs...never been touched with a grinder. Had one welded up last year to repair a broken rocker stand but other than that untouched. It's just a bracket car, so I wasn't concerned about going 5's in the 1/8 mile....I would have been happy with 6.50s, but when I saw the 6.08 last weekend, I was tickled to say the least.

 

Well, hypers would have saved me money, but I was actually leaning towards them because I thought they would offer better wear, and a quieter engine. From what you tell me I will likely stick with forged. BTW, sounds like your motor is a beast, congrats on the times

 

Another question, are you running a solid roller to spin those RPMs? I had no idea the stock Edelbrock springs were good for those kind of revs!

 

I'd save some money on the crank by going with a cast and then spend more money on good forged pistons. Hypers break a lot of times at the ringland because the rings are not gapped properly for them. Hypers need a different ring gap than forged pistons from what I've read.

I went with Scat because they have a great reputation for quality machining and I thought I would save money in the long run on balancing costs. I've heard Eagle cranks are really good too, but I've been told that the machining isn't as clean and balancing them can end up costing more.

To balance my rotating assembly they had to machine my balancer to remove weight, remove the weights on my flexplate and weld on new smaller weights, and drill some holes in my crank. Now my balance is closer to zero than 28oz, which is better. It only cost me $440 for all the machining and balancing. If they need to add those heavy metal slugs the balancing costs get real expensive.

Also, if you want boost in the future, just run a lower compression. Why do you want 10.5 or higher? I went with 13:1 because I wanted to have a bitchen race engine naturally aspirated that I could also add a power adder (nitrous) later.

Finally, if you want a quiet car, just put a turbo on it. Ask mavman about that.

Anyways, let us know how it goes.

 

I bought the heads bare, then added my own springs & stuff. Yes, solid roller.

The E springs weren't that much different than the PBM springs I'm using now. I looked them up online and compared them. Mine are 220 on the seat and the E springs were 195. Difference is max lift; E springs are good for around .600" lift, and my cam is a .700"-ish lift so I had to change springs. Even then, it's borderline as far as stacking coils.

 

Yeah I know a little bit about turbos. I built a custom twin kit for my Mustang. I wonder how a 408 would run with a lower compression ratio such as 9.0-1? If I can run it that low NA, then I will be set up for boost down the road. I dont want it to be a slug until its boosted though, so it may not be possible to build it like that. I keep going back and forth between a turbo in the future or not, but knowing if I can build this engine low compression and maintain NA power will help me decide for sure.