Of all the big-block builds in this issue, this one will have the most limited appeal, and we know that. To summarize, this article shows the process Westside Performance went through to build a better-performing big-block Chevy that looks like a stock, 325hp 396. Most people building an engine from scratch or freshening up their old one would likely go for bigger displacement, aluminum heads, and so on. But some people want their engine to look as stock as possible, including cast-iron heads and intake, but built to its fullest potential. We can totally respect that, too. Though that particular build won't post the big numbers of an engine built with aftermarket parts, some creative thinking will get better performance than the stock engine could have hoped for.
Whether you want to build a stock-looking 396 is irrelevant. The most important concept to draw from this article is how to gain the most performance from the parts you have. Working within limitations that seem to restrict performance bore size and combustion chamber shape, for example, forces an engine builder to come up with creative ways to work around these confines to build an engine that's better than the sum of its parts. With that in mind, let's take a look at how Ted Toki, owner of Westside Performance, put together a 461ci big-block Chevy that still looks like a bone-stock 396.
The Starting Point
This engine was most likely an L-36 396 out of a fullsize Chevy circa '65 or '66. The bore and stroke were originally 4.094 x 3.76. It had 10.5:1 compression with oval-port, closed-chamber cylinder heads and a Quadrajet carburetor on top of a cast-iron intake manifold. These were rated at 325 net horsepower from the factory. Not bad, but it could be better.
For comparison's sake, here are some other factoids:
396
402
427
454
BORE
4.094
4.126
4.250
4.250
STROKE
3.760
3.760
3.760
4.000
A popular big-block build is a 496-that's a 0.060-over 454 (4.310 bore) with a 4.250 crank. Most big-blocks have a 9.800-inch deck height. Heavy-duty truck applications generally have a 10.200-inch deck height.
Of all the strikes against the 396, the most egregious is its combustion chamber design. Early big-blocks had closed combustion chambers. What does that mean? Compare it with the later, open-chamber heads of a 454 on the left. The 396's intake valve is so buried in the chamber it has very little room to breathe. Air needs room around the valve to flow into the cylinders, and with almost half of the intake valve shrouded like this, it has nowhere to go.
396, The Bad News
As we walked into his assembly room, Toki told us that of all the big-blocks, a 396 is the least desirable-almost as if he were bracing us for bad news. "With the small bore size, there aren't a lot of pistons available. Same thing goes for the rings. Plus, the heads are terrible." It turns out they are. Let's investigate.
The Toki Solution
You'd need a micrometer to discover that the valves aren't stock. The intake valve is the same diameter as stock-2.19 inches, but the exhaust is 1.81 inches, up from the stock spec of 1.725. Toki says a bigger intake valve wouldn't help-it would be shrouded even more in the combustion chamber. In a cool piece of trickery, he did use Manley stainless steel valves with thinner stems. Stock 396s are machined for 3/8-inch valve stems (as are most big-block Chevys). These valve stems measure 11/32 inch. "I really don't know that it will make a difference at all, but they intrude into the port less. It couldn't hurt," Toki says. In addition to fitting the guides to the thinner-stem valves and adding hardened exhaust seats, Toki cut the spring pockets for bigger-diameter valvesprings and machined the guides to fit positive-style valve seals. Except for some minor hand blending to the exhaust port, no porting was done to the heads.
PARTS LIST DESCRIPTION PN SOURCE PRICE Assembly lube ACXAC-9900 Ackerly & Childs $8.99 Piston rings 1/16 Ackerly & Childs 138.00 Cam bearings FH615F Competition Products 29.99 Core plugs P102 Competition Products 7.99 Distributor driveshaft 8151 Competition Products 11.99 Fuel pump drive CCA4616 Competition Products 13.99 Funky parts kit FKC-3 Competition Products 7.95 Gasket set RB-31170 Competition Products 39.99 Long steel rockers N/A Competition Products 80.00 Oil pump N77 Competition Products 36.99 Hydraulic roller 396275/284 Isky 335.95 Hydraulic lifters 3970HYRT Isky 645.95 Timing chain set 73142 Manley 94.50 Distributor D100700 PerTronix 275.09 Wires 808290 PerTronix 60.87 Bearings 829KDSS Pro Comp 69.95 4.155 piston N/A Ross 917.00 4.250-inch crankshaft QT425 RPM 260.00 I-beam rod CBC6385-I RPM 525.00 Champion spark plugs NY8 Westside Performance 31.60 Intake valves 11872-8 Manley 150.48 Exhaust valves 11381-8 Manley 150.40 7-degree valve locks 13084-16 Manley 51.20 Springs 22408-16 Manley 161.60 Retainers 23645-16 Manley 52.00 Spring cups 42126-16 Manley 67.20
