B'klyn9C1

Happy New Year,

I have heard a lot of opposition to the use of 4.100+" cranks in LS3/L92 based stroker builds. Especially for use in daily drivers. I have a 1995 Chevy Caprice 9C1(the police package) and I'm about to swap in a LSx stroker with ported LS3/L92 heads and a 6L80E/6L90E transmission. A lot of people think that if the the motor doesn't grenade a week after the the customer drives out of the shop it is a great build. I am interested in a high performance street build with near OEM reliability, longevity and driveability. My LT1 has nearly 200k miles on the clock right with little oil consumption. My performance goal is to get 525+ RWHP/500+ RWTQ.

So guys please me tell the reasons why a 4.100+" crank in a Gen IV OEM stock block is a still "a bridge too far" even with custom shorter pistons???

I also would love to hear from those who have LY6/LS3/L92 based 427 ci in their daily drivers not just weekend warriors So tell me why a 427 ci, Gen 4 OEM block, 4.100" stroker cranker is great for a daily driver and why it would it last at least 100,000 miles with good maintenance??

Or is the 4.000" stroke the best overall compromise for a daily driver looking for near OEM longevity????

CETAWS6

iTrader: (2)

Well I have a LS3 that's 4.070 x 4.100 that is daily driven. I had it for over a year now. I haven't had any problems with it.

COPO9560

How much routine maintenance are you planning? To get 525+ hp, you will need a decent cam grind and springs will need replacement far before 100K miles. Either rotating assembly will likely include forged pistons - good for hard use, maybe not the best choice for a high mileage engine. Looser fit in the bore will lead to quicker ring wear. 4032 would be a better alloy for this engine than 2618.

Just curious why you are moving to an LS platform in this car. There are many good options based on SBC that can hit your goals and might be less expensive to assemble, especially when you add up all the little items for the LS conversion.

My choice for 427 is 4.125 bore with 4 inch stroke but this was not an option to choose. Good luck with your build.

gectek

iTrader: (2)

The only reason I would use the shorter stroke in the LS3 block is if you could save any money. Otherwise I see no other reason. For an N/A Daily Driver that is.

B'klyn9C1

Why go to the LS platform in a 17 year old B-body?? The short answer is the LSx is the future, better than that it is the present. Hey if they are putting LSx's into '60's and early 70's muscle cars then why not into a '90s era muscle car?

To get 500+ RWHP out of a LT1 I would need a real radical solid roller cammed 396 ci stroker. Not exactly very daily driver friendly. A 600+ FWHP LSx would still be a hydraulic roller cammed and still get half decent gas mileage.

Here are some points that tip the scale towards a LSx:

The Optispark ignition is shall we say "problematic".

Stock LSx ignition is used even heavily modified FI engines.

The EFI Connection LS1 ignition conversion cost $1000+

Unported LS3/L92 flow nearly 300 CFMs(intake) out of the box.

For LT1/LT4 heads to flow like from a good porter(CNC) cost over $1000.

Conversion kits are getting better all the time(e.g. S&P, BRP Hot Rods)

LSx come stock with a fairly high flowing midlength runner compostite intake.

LSx 6 liter iron cores(LQ4/LQ9, LY6) are now cheap and plentiful and are still lighter than a iron headed B-Body LT1.

My 17 year car old needs a new wiring harness anyway. OEM wires aren't top notch.

Good custom exhausts systems including headers for either LT1 or LSx are about the same.

Gen III and Gen IV PCMs are superior to Gen II PCMs.

Gen IV PCMs allow the use of GM six speed autos the 6L80e and the 6L90e with manumatic capabilities.

CAMSTER

iTrader: (10)

My vote is in for the 4" stroke, and the best heads, you should be able to easily reach your power goal, and them some...

racerfox

iTrader: (4)

i have a 418 ls3 with WCCH 245 heads and cam and i dd it and love it if you want great mpg honestly i would look into forced induction for same power goals and still good mileage. my car gets around 20 ish with some stop and go on hwy it gets about 24
my old setup with stock bottom and just heads cam i still got close to 26 hwy

bnvus

My vote is for the 417. To many professional engine builders are recommending to stay with the 4 inch stroke for stock block LS3. Play it safe and heed these warnings. The last thing you want to hear is I told you so. Plus you will be able to achieve your goal with that 417 no problem with the right heads, intake and exhaust. I am real close to those numbers with my 416 Goat. I am thinking about this for my Impala as well. But man is it a lot of work to do the conversion. Good luck.

430 hp 70

iTrader: (3)

pistons have changed, but i still hear that the 416 is the safest. personally i dont think the little extra torque is worth it for the added stress in decision making. youll most likely fry the tires off it anyways.

frogslinger

Good luck getting a 6L to work in a non canbus car... only one shop seems to have it half figured out.

gectek

iTrader: (2)

58x - 24x converter box seems to always work well......Not sure what you are really talking about there in any other case.

allblowdup

Go with the 416. The 427 is fine for a street runner or racer engine but if you are planning on 100,000 miles it aint for you. Even the 416 isn't the best for that kind of mileage. te problem is the short pistons and the amount they come out of the bore. Even though they are designed for that purpose they still are going to have faster wear than a stocker. Performance and reliablity can be had as long as you don't want to much of one without giving up the other. If all you want is 525 hp then go with the ls3 crate engine. That will go 100,000 miles.

gectek

iTrader: (2)

^ I am sure that incorrect information like this is what leads people to believe that the stroked engines are not good for DD's or for longevity.

Mike454SS

iTrader: (4)

That's not true at all. I've seen a lot of swaps, including a bunch of DIY ones, with 6L80 and 6L90 transmissions running just fine in them.

I can't wait to put LS power in my B-Body...the engine is done, I just need to get the Camaro back together so I can stop using my 95 Caprice as my daily driver.

redtan

iTrader: (5)

Really, so all those LSx swaps in 60s-70s musclecars are done by this one shop?

What about all those LSx swaps in early 90s imports, like Mazdas and BMWs? All done by this one single shop in the world that has figured it out?