[JimGnitecki]

I've been saying it for some time, but for anyone who needs more proof that the internal engine parts in the 03 / 04 LM4 engine are no lower in quality than those in the 05 LS2 engine, how about this:

Hot Rod magazine, October 2005, on page 31, reports that in developing the Corvette LS7 engine, GM beta tested key components by running them on the racetrack for a full season in GM's World Challenge Cadillac CTS-Vs while the production engine was being developed.

Because that race series limits maximum displacement to 5.7 liters, GM fashioned a big-bore / short stroke version of the engine to test the parts. They used a PRODUCTION 4.6 liter truck crankshaft to do it!

The Cadillac LAPPED the field in the 2004 season opener after starting at the back of the pack. GM will not discuss what horsepower that engine made, but has demurely admitted to "well over 500 hp".

I think our cranks will take a supercharger just fine . . .

Jim G

 

[rick418cars]

Jim,
I think it was a 4.8L crank, the LS series cranks are supposed to be good
to 900 hp., there several guys running over 1200 hp boosted with stock
6.0L cranks..............something else usually fails before the crank.
I have a 4.8 in my work truck Silverado what a wonderful engine,
very thrifty and powerful for its displacement.

 

[JimGnitecki]

Rick: Yes you are correct. The Hot Rod article misprinted 4.6 and I blindly copied that error.

Will Handzel, who used to run the GM Performance Parts division, says that the connecting rod bolts are the only items that should be changed as a precaution, if you go above about 450 to 500 hp. Use high quality available afermarket bolts.

Jim G

 

[Donna & John]

Actually, this applies to not only the truck crankshafts but other "car" crankshafts as well. A lot of the newer factory parts are really pretty high-performance. In the LS series motors for example, the powdered metal connecting rods are actually just as strong (stronger in some tests) than the GM "Pink" rods that were sought after many years ago by hot-rodders. And yes, the LS series I refer to covers the late model truck engines like the 5.3L and 6.0L; they are all based on the Vette LS1/6/2 technology and parts

The real weak link in the LS series bottom end is the rod bolts, then the cast pistons (not very far behind the rod bolts). The connecting rods and cranks can easily handle close to 600 HP very reliably.