LA stroker Cast or Forged crank???

[swinger340]

Going to be building a 360 based stroker motor. What is the longevity of the scat cast cranks on a 500 HP engine. Debating on cast or forged crank. Will deff. be going with forged pistons. H beams if I go forged, or I beams if I go cast. This will be a street strip engine, so do I say screw it, go forged and get it over with, or will cast be plenty strong enough for my needs and hold up for years? $400 more for the sake of knowing it will hold up better will not break the bank. Was originally thinking solid flt tappit, may bite the bullet and go solid roller.

 

[cannucky]

my Scat has 15,000 on it in a 524hp stroker including a 3000km in 36 hours blast this summer , this is a cast unit but it's an alloy , Brian at IMM convinced me it was a solid piece when I was ordering my motor even tho I too was willing to fork out the extra for forged , I personally would still get the H beams they seem worth the extra regardless .

 

[Bad Sport]

Going to be building a 360 based stroker motor. What is the longevity of the scat cast cranks on a 500 HP engine. Debating on cast or forged crank. Will deff. be going with forged pistons. H beams if I go forged, or I beams if I go cast. This will be a street strip engine, so do I say screw it, go forged and get it over with, or will cast be plenty strong enough for my needs and hold up for years? $400 more for the sake of knowing it will hold up better will not break the bank. Was originally thinking solid flt tappit, may bite the bullet and go solid roller.

I have been looking at forged myself, complete kit balanced is around 2100.00. Good to 800HP. It also depends on how high you intend to wind it, 7000 rpm range suggests forged.

I am in the same boat as you, can't make up my mind. I am leaning forged though for peace of mind, I've seen to many pictures of broken cast cranks.

Where have you been looking??

 

[1970Duster]

Go forged! This will leave room to upgrade the power output. Cast youre pretty much hitting the limit.
Also it's better to have piece of mind and always overbuild your motor then that Intended app. that way you won't have to worry about breaking them. It's what I did with my 340.

 

[swinger340]

I have been looking at forged myself, complete kit balanced is around 2100.00. Good to 800HP. It also depends on how high you intend to wind it, 7000 rpm range suggests forged.

I am in the same boat as you, can't make up my mind. I am leaning forged though for peace of mind, I've seen to many pictures of broken cast cranks.

Where have you been looking??

Will go with Mike @ MRL once I make up my mind. Been picking his brain enough, so he deserves my business. Real helpful, knowledgeable, guy and his prices are reasonable. 4" stroke I really dont see much sense in spinning it much over 6500 RPM

 

[66340SEDAN]

Stroker....forged

 

[Bad Sport]

Will go with Mike @ MRL once I make up my mind. Been picking his brain enough, so he deserves my buisness

I might give Mike a call myself, I've spoken to him a few times. He used to live real close to me before he moved to Chesaning.

 

[swinger340]

Go forged! This will leave room to upgrade the power output. Cast youre pretty much hitting the limit.
Also it's better to have piece of mind and always overbuild your motor then that Intended app. that way you won't have to worry about breaking them. It's what I did with my 340.

Kinda what I have been thinking. just in case I want more out of it in the future. never fails, every engine ive had in the swinger seems awesome @ 1st and then I get used to it and then want more.

 

[autoxcuda]

Cast is fine for 500 hp and under. And go with forged pistons and I beam rods so you won't have to clearance block. SCAT has a kit ready to go like that.

I know people say go forged and you will have room to grow. But what is the reality of the complete motor if you pump this thing up other 100hp to 575 to 600 hp. And the reality of the rest of the car that needs to go with it.

Even at 500 hp stroker, you won't be able to hook up on the street.

And when you jump from under 500 hp to 575-600 plus hp you are most likely going to need different:

-Heads
-Intake
-Carb
-Headers maybe (larger size)
-Different compression (maybe handled by different head, but may need different pistons)

I'm just thinking a 475-500hp motor has a lot of different parts than a 600hp one.

At that point you may consider starting from stratch and selling you complete running old motor.

 

[Bad Sport]

Cast is fine for 500 hp and under. And go with forged pistons and I beam rods so you won't have to clearance block. SCAT has a kit ready to go like that.

Don't you have to factor in RPM range as well? I have been told that if you intend to race and you are winding it to 7000rpm forged is better.

 

[rlevs]

well I would go with forged it is much stronger than cast just by the way it is made but that is just my opinion

 

[autoxcuda]

Don't you have to factor in RPM range as well? I have been told that if you intend to race and you are winding it to 7000rpm forged is better.

If you are winding a 4" stroke small block that makes peak power near 7,000 rpm, it is making well over 500 hp. Maybe well over 600 hp.

A 7,000 stroker will need various other racer mods to the block.

This is Guiter Jones' 7,000 rpm W-5 headed 408 stroker with a tall-filled block that runs 9.756 @ 134.67.


Do you plan to run high 9's and have a chassis that can do this?:

 

[mopardude318]

maybe later he would wanna add a turbo? or even a little B&M blower? a forged crank is not that much more IMO...but, what are you plans for the engine? ya might not NEED a forged crank...but there are also alot of things i dont need, but want lol

 

[340sFastback]

Forged crank and H-beam rods are heavier. Heavier means slower revs. Heavier means more stress on main caps. Go with forged if you need it but remember its not a plus in every category. You aren't going to make any power with a 4" crank over 6,000 RPM unless you have some really serious heads and big solid cam or you have a power adder.

I went with Scat cast and Scat I-beams because they are plenty strong for 500+ hp and they are lighter then the forged/h-beam set up. Have a good local shop balance it, get your block line honed, run ARP main studs, and get all the parts looked over by someone who knows what they are doing. Parts are important but prep and correct clearances/tolerances are also key.

As for pistons yes forged in a 4" engine.

 

[Abodybomber]

340fast nailed it.I started a budget build 408,in 04.The Scat crank has better metellurgy than a stock cast LA crank. A lot of issues I have seen,is the wider rod/ crank journal radiuses.You buy race bearings,or knife edge new stockies .That ,and a real balance job.

 

[srduster340]

At least get the forged crank. When the machine shop is finished balancing the assembly you would have spent enough for a forged crank. Don"t ask me how I know!

 

[autoxcuda]

At least get the forged crank. When the machine shop is finished balancing the assembly you would have spent enough for a forged crank. Don"t ask me how I know!

If you buy a forged crank kit that needs balancing, you will add the same cost to your build as a cast crank.

 

[inkjunkie]

maybe later he would wanna add a turbo? or even a little B&M blower? a forged crank is not that much more IMO...but, what are you plans for the engine? ya might not NEED a forged crank...but there are also alot of things i dont need, but want lol

Want to add forced induction you very well might be leaving some power on the table up front......got to watch the compression.....

 

[mopardude318]

Want to add forced induction you very well might be leaving some power on the table up front......got to watch the compression.....

true....i guess if it were me, id build it with a forged crank regardless...be advised though...... my stroker pic is in fact equipped with a....... SCAT CAST crank...
i got it on sale at Hughes Engines for 150 bucks...

 

[swinger340]

I dont need my car to go like Guitar Jones. LOL!!! I want it streetable. Although my duster is set up to rock and roll. Rail connected, mini tubed, caged, batt. in the trunk. Previous owner had her in the mid 6s in the 1/8th. With a w2 headed 340 and a 150 shot of NOS. Car now has a 450 HP 11:1 solid roller 340. It has a 3800 stall and winds up pretty well. Im looking for more torque without needing to turn 7000.

 

[moper]

The cast crank would be fine for you. The power curves for the stroker are totally different from the 340. So the peak torque is reached earlier, and maintained longer as long as the heads can support it. With gear they are crazy quick. Mild gearing they are still very quick off the line, and carry that torque into 3rd gear and over the stripe.

 

[Cudafever]

I dont need my car to go like Guitar Jones. LOL!!! I want it streetable. Although my duster is set up to rock and roll. Rail connected, mini tubed, caged, batt. in the trunk. Previous owner had her in the mid 6s in the 1/8th. With a w2 headed 340 and a 150 shot of NOS. Car now has a 450 HP 11:1 solid roller 340. It has a 3800 stall and winds up pretty well. Im looking for more torque without needing to turn 7000.

Every one that is pushing you to go with a Good "Q" Cast 4"Crank, is Right.!? It is a lighter assembly.(aka will wind up faster) You won't have to wind it as hard for the same power. "Aka" lower compression, pump friendly compression, that makes the same 450 HP as your 340. Only at a lower rpm.............But your not building a street car! your building a race Car,Right?
You are already making 450 HP Right? a good cast is good to 500 HP...............

I say build the forged assembly, and then, as $$$$ becomes available, Make It Faster, until your on the Coat Tails of GJ!!!

 

[Bad Sport]

Do you plan to run high 9's and have a chassis that can do this?:

I would like mid tens myself. I am shooting for the 500HP range with mine also.

 

[Bad Sport]

Good thread!!

 

[autoxcuda]

Every one that is pushing you to go with a Good "Q" Cast 4"Crank, is Right.!? It is a lighter assembly.(aka will wind up faster) You won't have to wind it as hard for the same power. "Aka" lower compression, pump friendly compression, that makes the same 450 HP as your 340. Only at a lower rpm.............But your not building a street car! your building a race Car,Right?
You are already making 450 HP Right? a good cast is good to 500 HP...............

I say build the forged assembly, and then, as $$$$ becomes available, Make It Faster, until your on the Coat Tails of GJ!!!

No, he has a Duster that is set up more race oriented.

This motor is for something else? that he wants to be street friendly.

I dont need my car to go like Guitar Jones. LOL!!! I want it streetable. Although my duster is set up to rock and roll. Rail connected, mini tubed, caged, batt. in the trunk. Previous owner had her in the mid 6s in the 1/8th. With a w2 headed 340 and a 150 shot of NOS. Car now has a 450 HP 11:1 solid roller 340. It has a 3800 stall and winds up pretty well. Im looking for more torque without needing to turn 7000.

Problem is this guessing game revolves around the target Horsepower and Torque of the motor decides to build. Problem is: he hasn't decided what motor to build yet.

Pick the cam, heads, intakes, etc then estimate the power your motor will make. THEN you have the info to what crank is NEEDED for that build.

Plan the motor build, stick with it, then pick the parts to support it.