If you’ve been around this hobby long enough, you’ve probably come to realize that engine building is, to a certain extent, just engine building. The block gets machined, the rotating assembly balanced, and then stuff gets torqued. You spend as much as you can on the good stuff, you cheap out in one place that inevitably comes back to haunt you, and at the end of the day you hope you end up with a stout new powerplant that can keep you happy for as long as it takes you to save up enough cash to do it all over again. At Vette magazine, we’ve covered hundreds of engine builds throughout the years, diving into the tech that really matters, all while trying to help build combinations that work well for the real enthusiast.
With the advent of the fifth-generation LT1 small-block engine, this tried-and-true formula remains pretty much the same. The camshaft goes in the same hole, the crank still gets held in place by the main caps, and the heads still need to be torqued in what seems like 500 different steps. However, not everything about the Gen 5 small-block is business as usual, and before you go ahead and pull those 6.2 liters of technology out of your C7, we suggest you do a little more research into the intricacies of direct injection, variable valve timing, and GM’s new take on many old ideas.
That’s not to say this can’t be done—quite the opposite really—but it is worth spending some time with guys on the cutting edge of the field before you end up wondering how quickly you can get a new high-pressure mechanical fuel pump from your local dealer. That said, when Howard Tanner of Redline Motorsports told us he was ready to tear into a new LT1, we were all eyes and ears. Redline, as you may know, has been on the forefront of C7 technology, and took the time early on to partner with other key shops, tuners, and parts suppliers to get a step ahead of the Gen 5 curve before it came barreling down the track.
This work up front allowed piston manufacturers like Wiseco early access to Gen 5 cylinder heads and pistons, while shops like Redline and Vengeance Racing were already working on new camshaft designs and supercharger combinations. Callies was quick to work up new crankshafts and connecting rods, while bearing manufacturers worked up solutions to the new three-piece thrusts. All of this came together thanks to an industry willing to push the boundaries while working with one another, and that hard work has culminated in the smashing of barriers (10- and 9-second C7s, 1,000+ horsepower street driven Stingrays, etc) in record time. A 416 cubic-inch stroker motor build for a C7 already equipped with a supercharger, long-tube headers, and more before the first six months of new car deliveries is even over? That’s progress, people! And now you can do it all yourself at home without having to learn as you go. Want to find out what’s new and what’s business as usual? Hang with us and Redline as we dig into a 416 cubic-inch Gen 5 LT1 build.
1. The foundation of the Stingray’s direct injection 6.2-liter engine is the all-new aluminum block, which features cast-over cylinder liners, deep skirts, and nodular iron six-bolt main caps, along with improved windage and larger M12 cylinder head bolt provisions.
2. The Gen 5 block is precision cast from 319-T7 aluminum and features new cast-in-place liners, which are encased below the aluminum deck surface. This smoother surface, combined with the larger M12 cylinder head bolts, allows for improved cylinder head sealing.
3. From the underside, the Gen 5 block looks very similar to its Gen 4 brothers, although every Gen 5 LT1 ships from the factory with polymer coated bi-metal crankshaft and connecting rod bearings.
4. Of note, the thrust washer has also been upgraded to a three-piece, 180-degree washer design that is laser welded during assembly for maximum strength and longevity.
5. The factory crankshaft is no doubt a stout piece, although Redline Motorsports had no use for its stock 3.622-inch throw. The new Callies Magnum crankshaft sports 4.000 inches of sling, which is enough to punch this little LT1 out to 416 cubic inches, while supporting big power down the road.
6. Note the difference in thrust bearing area of each crank. The Callies unit has a much softer filet for maximum strength, although that does require running a slightly thinner thrust bearing.
7. Not a deal breaker, but it’s certainly something to remember before you dig in to your own build at home.
8. Tried-and-true 6.125-inch connecting rods still work in the LT1, and these Ultra units from Callies have been withstanding big power in Redline builds for years. The ARP bolts, H-beam construction, and Timken steel forging make these a favorite of engine builders across the country (and if you’ve built an LS1 in the past, you’re already ahead of the game here).
9. Of course, the real magic of the LT1 is in the direct injection (DI) design, and as you can see from these gorgeous slugs from Wiseco Pistons, that magic is about as complex as it gets. GM is said to have spent more than 6 million hours on computational analysis to design the direct injection combustion system, and Wiseco’s job was to add strength, reliability, and performance without compromising the mixture motion and combustion characteristics of the DI system.
10. That combustion system also relies heavily on the cylinder heads and camshaft designs, which must all work together perfectly to create maximum efficiency and power. It’s worth noting that the LT1 features reversed intake and exhaust valve locations, along with large, straight rectangular ports to really take advantage of every bit of airflow possible.