What is the difference between an LS and a LSX motor?

 

Same thing, lsx is just the X being open ended for 1,2,3,6,7,9, ect.

 

Unless it is stated,"lsx block", which is gm's aftermarket performance block.

 

Lsx block weighing in at 240+lbs? Isn't that more like a boat anchor?

 

Isn't that more like a useless post?

 

You must not be up on the nasty amount of power that piece will hold. The weight is there for a reason. Not to mention the depth to make a 6 bolt main and 6 bolt heads.

 

Not particularly, the #1 reason I switched to LS power was the affordable aluminum block and heads. I'd have stayed with the very affordable early small-block line if it weren't for these light weight components.

 

Rated to 2000hp I think I read ?
http://www.gmhightechperformance.com...k/viewall.html
4.250 bore x 4.500 stroke....max

LSX Bowtie Block specs and features include:

Fully CNC-machined cast iron block
True priority main oiling
6-head bolts per cylinder
Standard 4.400" bore spacing
Extra-thick Siamese cylinder bores, ready for final honing
Semi-finished, machined thicker decks
LS7-style, 6-bolt dowel-located billet main bearing caps
Wet-sump and dry-sump oiling capability
Production-style deep-skirt head bolt holes
Production bolt hole and thread sizes
Maintains production exterior accessory mounting provisions
Front motor plate mounting holes added
Additional material cast around cam bearings for greater strength
8mm exterior/interior fifth- and sixth-head bolt holes
All five cam bores machined for bearing P/N 19167218 (supplied)
Standard 0.842" lifter bores
Accommodates all LS oil pumps and oil pans
External oil pump feed (rear of block)
Main web bay-to-bay breathing holes to support greater horsepower
Includes unique cam retainer, rear cover, lifter retainers and production style replacement cam bearings For the advanced LSX competition engine builder, you will fully enjoy reading the following features of the new LSX Bowtie Block:
Front oil feed holes can be plugged/restricted for mechanical flat tappet or mechanical roller lifter applications
Can be machined safely to 9.200" deck height
Maximum 4.200" bore at .200" minimum wall thickness (naturally aspirated applications)
Head bolt holes can be machined for 1/2" studs
Cam bores can be machined to accept 60mm roller bearings
Can be machined for larger diameter lifters and/or 1.060" bronze bushings
Front oil feed lines can be plugged and external oil pump and/or aftermarket dry sump systems can be used via oil pump feed at rear of block-may be required with certain large stroke/aluminum rod combinations
Belt cam drive systems can be accommodated-some machining will be required
Front motor plate can be used for racing chassis applications (sprint car, drag racing, truck pulling, etc.)
Threaded water plugs can be used for external heaters or coolers
Extra stock for main bearing align-honed
Orange Powder Coated

 

There were some wieghts taken recently of the LSX block vs others. 100lb diff between it and an aluminum block. Only a 10lb diff between and LSx block vs an iron 6.0 block.

Pulled from the thread:


LS7...............107
RHS...............110
Dart Billet......128
6.0L Iron.......220
LSX...............230

 

So to summarize Doug G's excellent post, an LSX motor uses a much stronger and larger iron block. The block allows larger displacements and will hold more power. It has to use LSx specific heads due to the extra head bolt per cylinder. But my understanding that extra bolt hole gives better head gasket sealing which means it should withstand more boost.

And like Zones said a LOT of people use the X like a wildcard symbol as a generic reference to the LS line of motors. But that is not the same as the GM LSX motors.

 

You can use any of the LS heads on the LSX block. You just don't get the advantage of the extra head bolts.

 

Correct.