Helping us decide on an engine...
Helping us decide on an engine for our Corvette was Editor Heath, who challenged us to build a first-generation small-block that would out-power an LS7. This is no small task, as the all-aluminum 427ci LS7 features CNC-ported heads, huge valves, a roller cam, and 11:1 compression.
To spin the camshaft, we veered from the antiquated "wet" timing-chain setup in favor of a much more advanced design, the beltdrive. Jesel has long set the standard in dry beltdrives, with kits that eliminate the timing chain and instead drive the cam with a belt located outside the crankcase. Here, it can be easily accessed for maintenance and to facilitate cam-timing changes. We also chose Jesel 1.6-ratio aluminum roller rocker arms for this engine, knowing that their shaft-mounted design, which places each pair of rockers on an individual shaft, is far superior to stud-mounted rockers and provides additional valvetrain stability.
Internally, this engine will have to be able to survive the abuse we intend to hand it, on both the street and track, so only quality components would do. A quick check of Summit Racing's catalog and website was all it took to find the components we'd need for a tough bottom end. Starting with a Scat lightweight forged crankshaft, Scat I-beam connecting rods, and Clevite engine bearings, we added a set of Mahle forged pistons that will bring our compression ratio to 11:1, just like the LS7. To oil this small-block, we ordered a Stef's aluminum oil-pan kit that includes the pickup and pump, also from Summit Racing.
We've already taken the new parts to our local machine shop, Auto Performance Engines, to have the necessary operations performed. Once the machine work is done, we'll assemble this 427-inch combo and use the shop's Superflow dyno to test and tune the mill. How much power will we make? We hate to speculate before the engine is even running, but we'll be disappointed if we don't handily top the LS7's numbers with our "old school," first-generation SBC. Let us know if you think we have what it takes, and how much power you think we'll make, at www.vetteweb.com, and be sure to follow the rest of this series as we build, dyno, install, and test our LS7-killer small-block.
Like many enthusiasts, we'd...
Like many enthusiasts, we'd long since become accustomed to the moderate level of performance available from our Vette's stock engine.
Building a powerful small-block...
Building a powerful small-block will definitely give our project car a shot in the arm, and perhaps a chance at a dragstrip rematch with Editor Heath.
Since we wanted to model our...
Since we wanted to model our small-block after the LS7 in terms of displacement and weight, an aluminum block was our only choice. Dart Machinery makes some of the best aluminum blocks on the market, and had just what we needed for our LS7 killer SBC.
The Dart block offers the...
The Dart block offers the wider, Oldsmobile Rocket-style oil-pan rail for stroker clearance...
...billet main caps, a raised...
...billet main caps, a raised cam position, threaded core plugs, and optional 50mm cam journals and raised deck heights. This is a true race-style block, but it still retains full water jacketing and provisions for factory motor mounts, making it ideal for street use as well.
To top our block, we chose...
To top our block, we chose Dart's 23-degree PRO1 cylinder heads with 227cc intake runners. Like the LS7 cylinder heads, these Dart heads are made from cast aluminum and feature full CNC porting. Ours came fully assembled with roller valvesprings compatible with our Comp roller cam.
The Dart PRO1 CNC heads offer...
The Dart PRO1 CNC heads offer a great combustion chamber with plenty of quench area, along with large 2.08/1.60 valves. We'll still be giving up some intake-valve area to the LS7's 2.20-inch titanium piece, but we plan to more than make up for that with careful cam selection.
Knowing we'd need a stout...
Knowing we'd need a stout rotating assembly to handle the planned output of this engine, we called Summit Racing Equipment and ordered a Scat lightweight forged crankshaft with a 4-inch stroke and 350-size main journals.
Scat 6-inch I-beam connecting...
Scat 6-inch I-beam connecting rods will also be utilized in this normally aspirated combination.