Kaase's Boss Nine Gets Blown

Jon Kaase has developed a series of Boss Nine engines featuring intake manifolds for 4150, 4500, and tunnel-ram carburetors, EFI conversion, and stack injection. Now, Kaase Racing Engines is proud to introduce their latest, a blower version. The blower will push the engine over the 700 horsepower mark and toward 1,000 on pump gas. The engines are available from 429-600cid with either a forged or billet crank. Jon Kaase has a lot to say about the latest in his badass lineup of Boss Nines.

Official Release:

Winder, GA: Seven months ago Jon Kaase introduced his new Boss Nine engine to much acclaim. Constructed with either a cast iron or cast aluminum block it was developed using five intake manifolds. These suit 4150- 4500- and Tunnel Ram-style carburetors, Keith Wilson’s EFI conversion, and Hilborn’s stack injection. But today’s news is of their blower version.

Fitted with heavy-duty bearings and special double-lipped Teflon seals for prolonged life, the BDS 871 series three-lobe standard helix blower proudly sits atop the mighty Boss Nine. In its naturally aspirated form it typically produces between 700 and 1000 horsepower on pump gasoline. Add to this the displacement of the BDS Roots-style supercharger (416cu in) and the 40-50 percent additional horsepower its makers claim, and hot rodders can expect much! One wonders if the crafty Kaase has considered a slight detune to maintain its flush of excitement and make it last forever.

Though a variety of engine capacities can be specified, from 429 to 600cu in, the most popular displacement has proven to be 520cu in. And so it is with the blower version. By using a 429 passenger car block with a .030in overbore (4.390in) and a 4.300in stroke ensures engine parts are readily available, making this the most cost-effective unit to build.

Like its naturally aspirated forerunner, the 520cu in blown engine uses either a forged crankshaft or the Bryant billet creation. The pistons, however, in the blower engine are very different to those of the naturally aspirated. With compression ratios of 8 to 8.5:1 Diamond’s low-compression pistons allow higher blower boost, producing lots of low-end and mid-range torque. Similarly, the camshaft was designed to eradicate any jerking and bucking at off-idle and part throttle in the low gears. Kaase resolved this problem with a camshaft design that sounds suitably belligerent yet beautifully drivable.

There is so much more to be said about this engine, not least the intricate work on the cylinder heads and timing gear, the full-race roller-tipped billet rockers by WW Engineering, the race-bred 3/8in thick-wall Trend pushrods, or the nostalgic Kaase Boss Nine valve covers.