I'm going to be using ETP 240 ls1 heads, would it be worth my while to build a 4.125 inch with 4.100 stroke lsx instead of ls3 block with 4.00 strock. This is with FAST 90/ NW 92.

 

after decoding what you said there, It looks like you are asking how much it would be worth to go from a 416ci LS3 to LSX 437ci correct??? Roughly the same difference as going from an LS1 to LS2. Correct me if im wrong someone, But on these engines 1 cubic inch is worth about 1hp, So you are looking at roughly 21hp. With all that said is it worth it?? Depends how important your dollar is to you. Most will say there is no replacement for displacement. I built a 427 LS3 and wish already I'd gone bigger (seems to be a problem with these LS engines someone always finding ways to go bigger) Money wise It seems about $1500 or so more to do the LSX, But its a better foundation for any future plans I personally like having an aluminum block but thats just an opinion. IF I could start over again, Id get a darton resleeved LS2 block (4.125 bore) and run the 4.1" stroke and get the 437ci. Best of both worlds aluminum block and strong sleeves. Hope this helped somewhat.

 

That's exactly what I'm asking. Would the weight be worth the extra money. The price on an LS3 has me leaning it's way, but the future build thing has me thinking about the LSX.

 

After talking w/ my engine builder, I'm going w/ the LSX.

 

I hate driving iron block vettes and f bodys. It really all depends on your end goal. I would go with a sleeved ls7 block if displacement was my goal and I had some free $$$ laying around. I would only do this in a NA build also.

 

Keep one more thing in mind. I hear the LSX blocks require a good amount of machine work. Now that might have just been the older block not the newer one, But I'd look into it a little bit.

 

Good choice. I debated on numerous build combos but in the end I decided to do it once and do it right. My Vette has been down almost a year, while I've been scraping together the pennies needed to build this thing bulletproof. I'm hoping for over 600 rwhp N/A with the option to throw as much spray at it that I want in the future....Again....Good Choice!

 

I can't speak for the older block since I have the newer one, but according to the machine shop, it wasn't bad anything out of the ordinary.

 

We just built a Wet-Sleeved LS7 468 cid for a customer's 08 Z06 upon his request..... He road races the car so he didn't want the added weight of the LSX block. For me though, for high HP applications, and for cars that are dragged or rr'd hard, I'd take the added weight of the LSX for the added safety. The LSX block is proven over 2500 hp...No way you can say that about a sleeved LS7....on top of that you pay as much if not more than the LSX costs to dry sleeve an LS7....Wet sleeves are even more. Just my 0.2

Yes, throwing a heavy LSX in the front of a C6 throws off the weight balance, but there are steps you can take to lessen the effect of the added weight.