447 HP Vortec Small-Block Build - Budget Sledgehammer
We show you how to build a solid, reliable 447hp Vortec small-block for less than $3,500.
From the February, 2009 issue of Popular Hot Rodding
By Steve Dulcich
Photography by Johnny Hunkins
There are many different ways to build an engine, and when the object is a 350 Chevrolet, it would seem they've all been tried. We've seen or read about our share of "low-buck" builds, so the very concept is nothing new. The challenge was to try to do it better. To us, the essence of a low-buck build is creating value, and our yardstick for that is power for the money. Making the most under these criteria takes very careful parts selection, beginning at the engine core itself, and an eye on the overall combination. To get to the punch line, our 350 made 447 hp on Speed-O-Motive's DTS engine dyno, and when every greenback we doled out was accounted for, we had change left over from $3,500.
Anytime such an undertaking is carried out, there will be some who will claim that they can make even more for less, and that may be. As we point out in our price list, there are a few areas where the budget could legitimately be trimmed here and there, and if you can save over our example, we'd congratulate you on a job well done. We list full retail on all of the parts used, including the cost of the carb, distributor, plug wires, and all those little items that usually get lost on some engine cost price lists, including the cost of the basic engine core. We stayed away from the trickery of the sweetheart deals, like claiming $25 for a swap meet carb, or a set of ported heads that a buddy was giving away while sweeping up under his workbench. Sure, those deals come along, and if you're lucky enough to find them, that's great. However, the retail prices we quote are what it takes for anyone to buy the parts we used, at least at the time this story was written. It can be argued that an individual engine build could be done cheaper, but we can say for sure that many have spent far more and ended up with far less power for their money.
A successful engine build comes down to planning, and for us, that began at square one-the basic engine core we used as our foundation. Chevy 350s were produced for decades, but we had a specific idea of what we wanted and why. Our core, purchased from AA Midwest, is a late-model truck Vortec or Gen II small-block 350. GM sufficiently refined the engine package to offer many improvements in quality. These late-model blocks can commonly be had with the robust four-bolt main bottom-end configuration, with an excellent factory windage tray arrangement. There is no debating the Gen II's superior gasket sealing systems, reducing the possibilities of oil leaks. Those features are nice, but the real advantage in our low-buck power plan is the factory hydraulic roller cam configuration these engines are designed to accept. With a factory hydraulic roller cam engine, we would gain the advantage of a roller, be able to re-use the factory lifter retention yokes and spider, the pushrods, and even re-use the lifters themselves. These items alone represent the potential for a significant cost savings, while reaping the roller cam's power and durability benefits.
We've seen scads of these late-model engines torn-down, and are always amazed to find remarkably low wear in the key components. Decades ago, the typical engine core would normally be worn to the hilt, rendering it unusable without extensive machining. In contrast, late-model engine cores routinely come in with negligible bore wear, and serviceable cranks, rods, and even pistons. We've heard many theories proposed to explain the readily apparent improvement in OEM engine durability, but what makes sense to us is the use of improved, lower-friction rings, closer control of engine tolerances and machining, better fuel management with fewer internal deposits as a result of EFI systems, and lower rpm with overdrive transmissions.
Our engine came direct from a core-supplier, and was simply plucked from inventory with no special selection involved. Once torn down, it proved to be a good example of what is normally found inside late-model blocks, showing negligible bore wear, and serviceable journal surfaces. There was some staining of the cylinder walls where the rings rested during storage, but our inspection confirmed that the engine was in good overall condition.
Our $300 Vortec 350 core came...
Our $300 Vortec 350 core came from AA Midwest, a leading core supplier. Our '98 vintage engine had four-bolt mains, a factory roller cam and serviceable crank, rods, pistons, roller lifters, and oil pump. After jet washing the block, honing the cylinders (with no overbore), putting in new cam bearings, and resurfacing the deck, we were ready to go. These operations are best handled by a pro, and we used the services of Speed-O-Motive in West Covina, Calif.
Exquisitely stock, our bottom...
Exquisitely stock, our bottom end was little changed from the way Chevrolet originally built it, including the factory 3.48-inch stroke cast crank and factory 5.700-inch powdered metal rods. Our block is one of the heavy-duty four-bolt main units, commonly referred to as a "truck-block," giving an added measure of insurance at our power levels.
It doesn't get any cheaper...
It doesn't get any cheaper than re-using what you've got, in this case the factory cast-aluminum dished slugs. Aftermarket flat-tops are a better choice, but these stockers will do the job if you're building "bucks-down." We simply cleaned what we had with Scotch-Brite, and freshened the assembly with new Sealed Power moly rings and Federal Mogul bearings-in standard size, of course.
Bill Shoemaker of Speed-O-Motive...
Bill Shoemaker of Speed-O-Motive slid the pistons in the bore using the slickest tool available for the job, a tapered ring compressor. While the tapered compressor is specific to only one bore size, common universal band-clamp or Lisle cam-lock style compressors work with any bore size you might encounter and can be had for pocket chang
Scrutinizing our bores shows...
Scrutinizing our bores shows no visible wear ridge, and the near-perfect finish was obtained with only a hone to renew the surface texture of the cylinder walls. This is common with late-model engine cores, as better rings, fuel injection, and overdrive transmissions have dramatically reduced the toll the bores take in service. We had a few surface stains on the cylinder walls where the rings were parked while the engine sat in the core pile, but we judged that to be acceptable. Plan on spending some bucks on machine work to freshen a stock block. We spent a total of $455, which included honing, jet washing, new cam bearings, deck resurfacing, and later on, cylinder head milling.
There is no doubt that re-using...
There is no doubt that re-using the factory pistons was a major contributor to our low-dollar equation, but the downside is contending with contrary aspects of the 12cc dish volume to the final compression ratio. The key here is the total volume to arrive at a power-producing ratio, something that requires the correct choice in cylinder head chamber configuration, and judicious milling and decking.
In the same vein of re-using...
In the same vein of re-using what's serviceable, the bottom end was assembled with the factory fasteners, which included the special hardware for the factory windage tray, which we were also re-using. An inspection showed the factory oil pump was in excellent condition, so that too was simply cleaned and re-installed, along with the original pick-up. The oil pan gasket is a premium FelPro one-piece design, since we're intolerant of leaks.