All New GM Performance Parts LSX Block - LSX-Tra

The other requirement is the use of a Gen IV front timing cover for the ignition pickup mount, as the rear-mounted Gen III system would have interfered with the optional larger diameter cam and cam bearing journals. LS1 owners fear not. Thom Bates, GMPP marketing specialist, reports that for about $100 retail, an LS2-style front cover comes complete with the ignition sensor and seals.

Everything else on this block can use all components from any LS-series engine, including the LS7 internal-mount dry sump oiling system. The block even has provisions for an aftermarket external dry sump pump.

Since iron was chosen to create the ultimate big-bore racing block, the price of the block is significantly lower than the factory LS7 block. GMPP reps realized that more of these blocks will probably find their way into big-bore street vehicles, so they took great pains to cast in and machine all accessory and street-necessary lugs and bolt holes to run it in a street car, and to ensure that it would run cool and collected under all predictable street conditions. Bates told HPP, "We worked very closely with the GM Powertrain engineering team, which has thousands of hours of testing on coolant flow models for the LS engine series, and we have no problem recommending this block for street use at maximum (4.250-inch) bore with no cooling problems." Hmmm, how about a 500 ci LSX blown nitrous street car that puts out 1,000 hp? I immediately envision a glove box full of speeding tickets

Since this block is over-engineered for almost any reasonable engine build, or even for most racing classes, Bates also stated that there is plenty of extra material that can be "profiled" (machined out) to lighten up the block significantly. Guesstimates are that simply boring the as-delivered 3.99 inch bores out to the 4.250 maximum would drop approximately 20 pounds from the block, and if you don't need the block to survive 2,000 hp, there are plenty of other places that material can be safely removed.

Another point made by Judson Massingill of SAM racing, a well-known racer of LS-powered cars, is, "I have to meet minimum weight requirements per class rules and have to add weight to the car anyway, so the weight of the block is not a problem. Ring seal at high rpm with the old blocks is more of a problem."

Conclusion
It would appear that GMPP has put a large displacement race-ready engine block within easy reach of the performance-minded LS-engine community at a price that most can afford. If you're considering a major engine build on an LS-series engine, it is probably something that you should look into. But perhaps the greatest testament to the durability of this engine block is that it could be the last one you ever need to buy, no matter what you intend to do with it now or in the future-and the future looks very promising for the LS-powered cars.