We all love small-blocks, and many of us love cubic inches even more. But, let’s face it; the 350- turned 383-c.i.d.”stroker” (a normal stock-block engine with the “stroke” of the pistons increased through the use of different internal parts to increase displacement) has been done to death. It’s about time that someone does something a little different. Unfortunately, “different” usually translates into “expensive” in car language and it’s hard to beat the value of a good 383 stroker.
While bench racing with some buddies one afternoon, we learned of a unique stroker project being put together by Sod Bogosian, owner of Hye Tech Performance (in La Puente, California) builders of the high-performance small-blocks (and big-blocks). Bogosian was going to build a trick stroker small-block using a custom-machined 4340 forged crank with JE pistons and the Street Avenger line of products from Holley.
While Bogosian’s approach to building this stroker was a bit unorthodox, it certainly wasn’t out of the scope of real street power. And the best thing about his idea was that it’s totally streetable and very affordable, thanks to the parts that he chose. We hit him up for the opportunity to peek over his wide shoulders as he assembled this new stroker.
THE MAKINGS OF A UNIQUE STROKER
Any time that you’re able to increase stroke in a street engine package you’ll typically gain additional torque. Since 350-c.i.d. small-blocks are notoriously lacking in torque when compared to their bigger brothers, spending money on a stroker crank kit and new pistons is a wise investment. Traditionally, stroking a 350 meant custom machining a stock 400 small-block crank’s 2.65-inch mains down to fit the 2.45-inch diameter main saddles in a 350 block. The 3.75-stroke 400 crank combined with boring the block 0.030-over ads about 33 cubic inches to the mix giving the owner a 383-cid small-block that’s very torquey and very affordable to build, but also very common and consequently boring.
What Bogosian wanted to do was take an aftermarket stroker small-block crank that already has the 2.45-mains and offset grind it further to give the engine a little longer arm. He picked up a 4340 forged steel crank from C.A.T. Power Parts and massaged its rod journals enough to yield an odd, but effective, 3.832-inch stroke. How he’d do it, you ask? By machining the rod journal diameters down to the 327 engine’s size of 2.00 inches. Thus, affordably offset grinding the journals to save money.
And since C.A.T. also offers 4340 H-beam connecting rods for the 2.00-inch journals, this operation added another 8 cubic inches to the mix without adding 8 cubic dollars to the cost. Not a huge increase in anybody’s book, but it offers a lighter rotating assembly thanks to the slightly smaller rod journals on the crank and can still pump up the torque numbers of your small-block. This, combined with Bogosian’s choice of 5.7-inch long rods and lightweight JE forged pistons means that this 391-c.i.d. stroker will rev like a much smaller engine, but still make the torque and power of its 383-c.i.d. cousins.
CLEARANCE TO RUN
Dropping a crank with a longer arm in a small-block that was never meant to have it requires a little forethought and some extra work. One place where all 350 blocks will need attention is creating extra clearance along the oil pan rails. That’s because the longer stroke will make the connecting rods hit the block, especially in the back on the No. 7 and 8 rods. This “clearancing” can easily be done with a die grinder and carbide burr. Although Hye Tech’s chief technician, Roland Marquez, goes the extra step and fully polishes the area that he’s ground for clearance, you could get by with leaving it rough ground if time and effort are a factor.
Another part that additional stroke can kill is the camshaft. The top of the connecting rod bolts on stock and some aftermarket I-beam rods will hit the cam lobes. To fix this problem, the top of the rod bolt can be ground on a bench grinder or, as Bogosian chose to do, you can have your cam ground on a reduced base-circle. This means that you’ll have plenty of cam clearance and the rods will not lose any of their engineered strength. There are also “stroker” H-beam connecting rods available to clear up the problem completely. Grinding a cam this way will not make it unusable in any other block either, so your cam can still be swapped out and run in another engine at a later date. The only drawback to running cams with reduced base circles is that custom-length pushrods are usually a requirement as well.
The last spot that needs attention in a stroker small-block is the oil pan. Although the crank and rods won’t actually hit a stock oil pan in any spot, to really get all of the power out of a stroker package, you need to move the oil further away from the increased stroke to control windage. Milodon came to Bogosian’s aid in that department and supplied a low-profile stroker pan to clear up any problem. Along with the new pan, Bogosian chose to use a high-volume Milodon oil pump and pickup, and he even installed Milodon’s Diamond Stripper windage tray to further control the oil. Although the tray does require a bit of notching to clear the factory dipstick, it’s an otherwise bolt-on part.
LET IT BREATHE
Since any engine’s limiting factor lies directly within its induction package, Bogosian knew that he’d have to bolt on some good-breathing parts. He turned to our friends at Holley Performance, who supplied their Street Avenger cylinder heads. In fact, Holley engineered a complete induction package for the Street Avenger line, taking the guesswork out of correctly matching components for the best power. Holley’s package includes new aluminum heads with matching flat-tappet hydraulic cam, timing chain, intake manifold and carburetor. Since this is just the first installment in this engine assembly’s life story, we’ll give you more details of the induction package in Part II. For Part I in this series, we’ll outline the short-block build-up in detail. And follow up next with the top end and finally, a dyno session to see how much power this wild puppy can really crank out.
Stroked to Perfection
Here’s an abbreviated recipe for the perfect “stroker” bottom end.Actual displacement: 391 cubic inches
Block: GM 4-bolt main bored to 4.030
Crank: C.A.T. 4340 forging with 2.45-inch mains and 3.832-stroke
Rods: C.A.T. 4340 H-beam, 5.7-inch, 2.00 journal, bushed pin end
Pistons: JE PN 183119 flat top forging, floating pins
Rings: JE ductile iron, moly-coated
Bearings: Clevite “H” series
Hardware: ARP main studs and bolts, ARP cap screws in rods
Oiling: Milodon high-volume pump with windage tray and “stroker” oil pan