Which is better and why? Will the 440 rev faster? Any other Variations?
This will be going in a GTO, looking for 600rwhp on motor and can handle a 200shot.

 

Which ever has more power will rev faster. Whichever has more power will accelerate faster. Not a huge difference between them actually. The 454 will have a lil more TQ and a wee bit more power all else equal.

 

Any other insight on this?
I see alot of people building the 440 but not so many doing the 454.
Why is that?

 

441 is the LS7 block 4.125 bore X 4.125 stroke = 441

No sleeves or LSx block needed to go 441

However, shooting a 200 shot on the stock ls7 sleeves ? I've heard good and bad. But most of the problems are probably related to the tunes they had.

By the time you sleeve a ls2 block, it costs a lil more then the stock ls7 block, but you can go to 4.185 bore.

 

Well the new LSX block is a lil better but on the old ones it was iffy at BDC with the bigger stroke 4.1250crank.

 

What about 4.185 bore X 4.000 stroke = 440 ???

 

What about reliabilty? 440 vs 454 ?

 

I had the exact same goals you have. I called several places and the motor I ended up buying is what was recommended. I didn't want the extra weight of the lsx block, and the RHS didn't exsist.
The larger motor could make a little more power but I don't think you'd feel the difference. My motor is two years old now and has been perfect. It's currently getting a 200 shot installed, so we'll see how that goes.

 

Doing a 440ci using an LS7 block, just boring it and stroking it......not re-sleeving it....with a 200 shot....might just last for one shot and then go BOOM. The stock LS7 sleeves are weak to begin with. They usually spilt at the tops.

Doing a 454ci with a resleeved LS2 block would be nice if you stayed N/A. But a 200 shot I think makes it a crap shoot at 4.185 bore, might kill the gaskets pretty fast.

If you want to spray a 200 shot....IN MY OPINION, do a 434ci using a resleeved LS2 block. 4.155 bore x 4.0 stroke. It'll be strong and have alot of gasket.
Or like a friend of mine has.....iron 422ci (not an LSX iron block), spraying a 300 shot now for like 6 years on it. Makes 880 RWHP. Daily driver, sprays the thing all the time.

.

 

N/A...great.

200 shot.......BOOM.

.

 

I agree if it's a plate system.

200 shot all day IF it's a direct port and well tuned.

 

I was told no go on the 4.185" bore with a 150 shot. If you wanna run a 440 and a 200 shot go with the Superdeck 1

 

I mean 4.185 bore X 4.000 stroke = 440 WITH LSX BLOCK!!!

 

If I were you I would do a 4.125 Bore x 4.100 Stroke. That works out to a 438.

I think it would be better off for a few things. For one it will allow for the wall on the sleeves liners to be thicker and that will help keep them round and will help remove heat. Next you will get a little better rod ratio and with the pin being a little lower down it will allow for a better ring package. You may think .025 is not much but having that to play with sometimes really helps.

It all matters on the block and all the parts you want to use. If you try to stick with all off the shelf parts you can do it fast and a little less money, but you may not always get the best results.


Best of luck

 

Doesnt matter if its iron, theres not alot of gasket between the cylinders....FOR NITROUS.

N/A.....go for it, it'll be great.

If you want to spray, let the nitrous do the work and go smaller bore, like 4.125 or less.

OR....if you must have a big cube engine AND nitrous, go 4.125 stroke and 4.1 bore = 436ci. It'll be fine and last a long time. Just call it a 440ci, nobody will know......lol

.

 

I thought LSX block can take 150-200 EASILY!

 

I've read a lot of engine builder's comments that the LS7 block is good to about 1000hp, boosted or sprayed. LS6427, you seem to think it's closer to 850. Any reasons why?

 

440 if you want to spray it.

 

The LSX iron block can probably take a dual stage 600 shot with no problem all day long......if its built right. I'm just saying, if you bore the LSX iron block to 4.185 you won't have much gasket between the cylinders and you will blow that gasket pretty soon, possibly the first time you spray it with a 200 shot, unless the tune is just PERFECTION. But it still won't last long that way with a 200 shot.

.

 

That is right on about the space between the bores.

You need to keep in mind that the thinner the gasket area is between the bore the harder it is to keep it from spliting or melting. If you feel that you will never be off in tune up then you will never have a problem, but I feel safe saying that no body ever feels safe saying it will never happen. Thats why a racers #1 saying is " it should be good ". We just don't know.

I would play it safe and not build a NOS motor 4.185 bore. Go 4.15 or smaller and get it larger by doing it with some stroke. Just make sure you have good rod angles. The new tall deck stuff really opened up what can be done.