Danny

iTrader: (16)

Hey guys,

I just bought a used LS2 block and I want to use it for a special project I have coming up. I’m looking into building a big inch motor that can withstand boost (15-18PSI), if I decide to throw that into the mix later. But for now it will just be an N/A motor with maybe a 250shot. I wanted to know how big can these blocks be bored out to (safely) when they’re re-sleeved. I was looking into Darton dry sleeves as a replacement for the sleeves. I was thinking of building at least a 440cu or 454cu with a 4.185” bore. Obviously the 440 would require a 4.000” crank and the 454 would require a 4.125” crank.

So here are my questions...
1). Would a 4.185” bore be too big for reliability (say for 15-18PSI of boost)?
1). If I decide to build the 454cu would the 4.125” crank require any modification to the block (maybe some clearance issues)?

This isn’t an “all out” build, just a strong street strip combination. I know a N/A and a boost engines are build differently sometimes (different pistons, rods, etc) but I just want to know if using this size bore and stroke is reliable. If I wanted to add boost in the future I want to be able to know that I can just swap the pistons and be done with the bottom-end.

Thanks in advance guys

Steve - Race Eng

iTrader: (1)

The Darton dry liners will go to 4.185" bore but naturally aspirated only. I would keep the bore size at 4.155" for any nitrous or boosted application to keep a bit more real estate for the head gasket to seal on.

Cometic makes a Phuzion head gasket in 4.180" bore only as I recall. That will work fine on a 4.155" bore.

When I install these sleeves, I cut rod clearance notches in the bottom end included in the pricing. The notches are deep enough to clear a 4.25" stroke with most rods.

Steve

Danny

iTrader: (16)

Steve,

Thanks for your reply. Ya, that's what I figured but I wanted to get a second opinion? The last thing I want to do is go to thin on the sleeves and end up regreting it later.

I'll just go with a 4.150". With a 4.125" crank that'll still give me 446ci which is plenty of torque for the weight of the car.

How much do you charge to resleeve a block like this if I were to take you the sleeves? I think my buddy can get them for me at cost but I just need to have it resleeved and bored to spec.

Thanks again Steve.

Shawn @ VA Speed

iTrader: (3)

you need to stay at a max of 4'' stroke for n2o or boost. this will keep a decent piston in the thing

1toofastlt1

iTrader: (4)

I hear that with a 440 ls2 long sleeve with a 6.25 rod will have problems with burning oil. Is this true that the oil rings wont seal good due to the placement of them over the wist pin????

Danny

iTrader: (16)

Guess I'll stick to the 433 I first had in mind.
Thanks for the reply guys.