5.7stroker

iTrader: (36)

I remember back when AES was pushing the 390ci combo hard for force induction setups. The logic behind it as many of you know was that a 4" stroke was hard on the skirts since the bores of the gen 3&4 6.0L iron block are short and pistons at BDC come further out of the block when stroking to a 4".

Hence AES promoting the 390ci and using a shorter 3.825" callies crank with 4.030 bore on a gen 4 iron block. Still not as easy on the skirts as a 3.662 stroke, but not as hard on the skirts as a 4" stroke.

Since piston design has improved over the years, it seems that the use of 4" strokes in applications where the car is a weekend warrior that sees the track 4-5 times a year are far more common these days over the use of a 3.825 or 3.9 crank with little concern of skirt wear simply due to less use on the motor. Seems like 390ci is no longer a thing on these stroked iron setups and many just go with the 4" stroke / 4.030 combo and make it a 408 if using a gen 3/4 block, or go 427+ if using the SHP dart ls next block.

I was considering a L96 block and just leaving the rotating assembly stock and just seeing how long I can make it last on boost pushing the 1100-1200hp limit but running it much lower than that on the street (vs upgrading the rotating assembly). Then I got to thinking about skirt wear and if I should go to a 4" stroke or a 3.9". Then I got to thinking about the hp limitations of the block itself and by the time the machine work is done on an L96 block + cost of the rotating assembly + putting on a different set of heads to tie it all together, you have to step back and take a look at what that costs vs doing the SHP dart setup and addressing the concern of the block being the weak point. I'm not looking to make over 1200hp and when I do push it to around there, it's only going to be at the track. So my options are to keep it around 1000hp and be somewhat durable or spend the $$ and do it right. There's just something about going the cheap way first and seeing how long it will last vs going the other route. I'm still undecided.

99 Black Bird T/A

iTrader: (4)

In my opinion if your doing Forced Induction, skip the stroker crank. Just increase the boost a slightly to make up for the loss of cubic inches. Many times 5.3's and even 4.8's can be pushed to 1,500 hp with forced induction.

The 4 inch stroker cranks work great in NA applications when the correct taper piston is used.

5.7stroker

iTrader: (36)

I guess the trade off is more heat generated with more boost to hit the same number, no?

99 Black Bird T/A

iTrader: (4)

Agree there are always trade off with all of it.

Probably just a few pounds of boost to offset less cubes due to not having the stroker crank. Maybe 2 pounds of extra boost or even 3 pounds of extra boost of off set ~30 to 40 less cubes?

A good set of ported heads would probably help offset the heat issue of 30 or so less cubes and slightly more boost.

One of the true guru's who used to post frequently implied the 4 inch crank really wasn't worth it on most FI builds.

5.7stroker

iTrader: (36)

Yep and the you get into the discussion about 427 stroker engines with 4” crank and boost always being faster than the smaller cube engine with boost. The durability factor gets mentioned with the smaller cubed engine but that argument loses ground when you start to get into the higher hp applications. There simply becomes a point where if you want 1200 hp that’s very durable and you want to run mid 8’s in a car that isn’t gutted, you have to pay the premium and step up to the aftermarket block or just accept the fact that the setup can let go at the track at any time. Could be the 5th pass, could be the 200th pass. I think some people that can afford it would be happier with a dedicated street car and a dedicated track car instead of trying to mix them both into the same application.

DualQuadDave

iTrader: (6)

My opinion is if you are boosting, building a stroker is a complete waste. If you want to go faster, put the $$$ in the heads/valvetrain/FI side. Making the motor physically bigger cuts the lifespan and makes for a whole new world of problems. Making the induction more efficient and it will make power w/ less stress/boost.

vorteciroc

I feel 5.7stroker should pose the following question to everyone:

Should preference lean towards a shorter stroke 390" engine built with an aftermarket block and rotating assembly...

-or-

Build a 408", 4.000" stroke engine with an aftermarket block and rotating assembly?

5.7stroker

iTrader: (36)

Yes with the stipulation that both combos will see boost. I came across this 2017 article which states:



The article mentions a 3.900" crank and the question takes it another step further with the 3.825" crank used in the 390ci.

https://www.hotrod.com/articles/choo...-engine-build/

Razor

I've debated the exact same options in my car.

But, I've decided I don't hate money and am more than happy with a 900-1000 hp car.

Lots of engine builders putting together 4" stroke motors for forced induction applications with the correct piston taper for a stock block. Look at LME for example.

K1 still makes a 3.9' stroke crank. Also, the brand new 6.6 GM engine has a 3.86" stroke, forged CCW crank that is already being exploited for stock LS block use.

Once you start down the DART block road, everything naturally tends to get "next leveled". Rods, pistons, crank, heads, etc...

5.7stroker

iTrader: (36)

Yes there's definitely an increase in cost the moment you start going past 1000 hp. I think this is why many guys just stick with the factory blocks and modify those along with good weight reduction to hit their ET goals rather than going with the aftermarket block route. The costs go up quickly when you start to go past 1000 hp while still wanting reliability.

Razor

Pretty much nails it.

1000hp in just about anything is fast. With that, I'll take the torque curve offered by the bigger displacement/larger bore (4" +) engine at a lower RPM.

5.7stroker

iTrader: (36)

Are you using a 4.030 bore with a 3.622 stroke then?

Razor

Just pulled that combo apart last week. If I buy a new crank, more than likely it will be a Callies 4.0 CCW.

5.7stroker

iTrader: (36)

That's a bad *** crank for sure.

Razor

Time will tell.

Good luck with your choice. Easy to get spun up and want to spend a ton of money after reading the internet.

ddnspider

iTrader: (26)

The more power you make NA the more power you'll make boosted. Plenty of people go 10s of thousands of miles with 4 inch stroke setups that are boosted without issue.

Che70velle

iTrader: (6)

Nailed it right here.

5.7stroker

iTrader: (36)

So in a nutshell:

If going aftermarket block, a 4" stroke is a fine choice. You'll make excellent power boosted with a block that is not being pushed to it's limits at 1000 fwhp, and can certainly go over that amount of hp without issue providing that the block is properly built for it.

If staying with a stock iron 6.0L as the starting point, mill it 4.030 and use a 3.662 crank because even with a bigger crank making more displacement and more power, your limited by the block itself and are pushing the block to it's limits at around 1000 fwhp. Upgrade the internals if planning to be around the 1000 fwhp limit if you want the block to last longer. You have the option of going with a bigger crank like a 4" and it will require less boost to hit the 1000 fwhp limit, but you need to account for piston design as well. This will result in less turbo lag on the street at reduced boost level due to the larger displacement.

ddnspider

iTrader: (26)

I ran a turbo in a 5.7 stock block with a 4" stroke, no issues because piston design from major manufacturer's accounts for this for 99% of peoples setups. Go with a name brand like Wiseco, Diamond, etc. and you'll be fine.

5.7stroker

iTrader: (36)

Even if you are boosting past the durability limits of the stock rotating assembly? Seems that if you are upgrading an iron block with a new rotating assembly to make it live longer and putting enough boost to what the limitation of the block itself is, might as well go with the 4" stroke because a K1 4" crank for example is pretty much the same price as a K1 3.622" crank. As long as you have the correct pistons, why would the 364 making 1000hp be any more durable than the 402 making the same power but with less boost?