I decided to pass on a tall deck due to additional complications and timing.

The next option is going with a 454 (4.125 bore / 4.250 stroke) with an off the shelf rotating assembly, ETP LS7 heads / LS7 intake. Is that attainable and are there any complications that I should be aware of?

My second choice is 441 (4.125 bore / 4.125 stroke)

 

Also, what else would I need for this build that I cannot rob from my LS2?

 

you sure the sleeves are long enough??

 

There are a few threads on sleeve legnth that we have gone indepth on, on this particular subject. The stock sleeves tend to be to short for a "optimal" ring pack in the 4.100" and bigger strokes. You can still get a decent N/A ring pack with the 4.100" and 4.125" cranks, and if using a piston designed for the long stroke, it shoud hold up fine. I would highly not recomend the 4.250" on the stock sleeve legnth. If you would like to use the longer strokes, your best bet is to ditch the LS7 block and go with the LS2 block, resleeved with Darton LS7 sleeves.(which are longer) Then you would have a longer overall sleeve that can support the piston at BDC and you will be able to get a larger bore. (up to 4.190")

 

is it safe to run a 4.125 stroke on the ls2 resleeved block. I was told there are oiling issues with the larger crank and I was told the ls7 sleeve is longer than the resleeved ls2. That's what I was told by a certain engine builder. They recommended not to go any bigger than the 4.0 stroke, but those extra cubes would be nice. And I would like to throw a 200 shot on top of it.

 

thats a huge motor

 

If you are looking for a 454 the best combination would be 4.185" bore 4.125" stroke. This can be done with either an MID wet sleeved LS1 or LS2 or a Darton dry sleeved LS2 or LS7 block.

I have done a couple of blocks for this sized build. The April GM High-Tech Performance magazine has an article on Bob and his son, Jim Obrizok's 455 Firebird which uses an LS1 Darton MID block I did for them.

Steve

 

Now this man appears to know what he is talknig about and then some!

 

Do a 447ci, 4.125 stroke for real good piston support and a 4.155 bore. That is if you're doing a resleeved block using the new 5.800" long Darton sleeves. 4.250 is supposed to be ok for those long sleeves but why push it for a few extra cubes. 4.125 stroke with those sleeves has great support. You probably already know the stock LS7 sleeves suck and are short, and a 4.250 stroke will spell disaster if it'll even work.
Talk to Steve at Race Engine Development, he helped design them and explained all this to me already.

edit: I see he already chimed in


.

 

Steve,

Did you say that 4.185 will be strong enough for N/A, but not if you're gonna spray it with say a 200 shot?


.

 

What exactly is ring pack?

 

am i the only person here that thinks the best option is to just hold out for the LSX block?

 

The rings on your pistons. You know, the things that keep the oil from blowing by. There's more than one (3 to be exact), and they are spaced according to how much room you have with the stroke/rod legnth avalible. Cramming alot of stroke and using the same rods tend to "tighten" the rings together, which can cause problem if they are to close together.


It's only the best option if you can get over the added weight. Adding 140 lbs. to the front of the car isn't "optimal" when you can get a aluminum block with close to the same bore.

 

Beast, what is your bore x stroke?

And when are you gonna finish that damn thing????????LOL

Can't wait!!!

 

a couple of things...

1) WHERE DO YOU WORK AND WHERE CAN I GET AN APPLICATION!?!?!?!?

2) why the hell do you need all that motor!? is it going into the vette in the sig??? if it is then it appears to be more of a streetcar... which brings me back to my original question... why do you need all that motor?

i'd just stroke the stock motor. have the stock ls2 heads ported, and throw a 4" 4.1" or 4.125" stroke crank. 402/412/415 inches. n/a that would be VERY potent for a street motor. and i'd say hold off on the big shot on an alluminum block. for durability's sake, i'd say just keep it to a 150shot.

but that's just MY opinion. either way - good luck, and let us know what you end up doing and how it turns out!

the vette looks sick!!!

 

4.155" bore x 4.185" stroke. I'm starting assembally this week.

I can't speak for him, but I did it to have something completly diffrent. Not to mention the HP/TQ will be on the next level. It may even be "to much" for the street, but it should be fun.

 

Are you just really against doing a 427?

I mean, I can understand someone wanting a 455 Firebird, but I would think if your goal is to go X speed and quickness on X dollars, there would be better money spent elsewhere. 454 might be a classic Vette engine displacement, but so is 427.

Also, have you considered the LSX block? Is it out yet? I don't know what dsplacement it can be taken to, but 'm pretty sure it's more than the LS7. You'd be adding what, 150 lbs? I bet you could get that back with a battery relocation and aftermarket engine cradle.

Don't mind me, though. Just talking out my *** here. I can barely afford a forged stock displacement bottom end here.

 

yea beast I have been waiting a long time also! Glad to hear you are starting this week!!!!

 

that's exactly what i mean - with the h.p. and torque of a motor that size... in a lightweight streetcar.....

he's going to need to ditch the wheels and tires for ice skates!!!

a 402 ls2 w/ ported heads and a decent cam will still make spirited driving a challenge on the street with street tires.

i can see where you'd want to have something different... but damn!

 

You can never have too much power!!!