For an engine builder to develop a personal project completely out of the ordinary, it takes thinking outside the box. Hood Performance‘s Alan Hood has certainly achieved that feat with the construction of this 442-cubic-inch small-block Oldsmobile engine for his personal 1971 442 Olds street driver. Making big-block displacement out of a small-block foundation took a bit of work, but Hood was after something different.

“When you’re an engine builder, you get a little bit numb to building small-block and big-block Chevy engines, ’cause you’ve done every combination imaginable. For the money spent on this, you could probably build something for power cheaper, but that wasn’t the point of this build,” Hood tells EngineLabs.

It’s quite out of the ordinary in that he selected a 1985 5.7 dx diesel engine block to serve as the foundation for the project, not the typical Rocket block  or big-block casting. 

“This block is heavy-built with material. A lot of the drag race Olds guys use the diesel block – it’s similar to the NASCAR ’80s block. I cut down the OD of 4.25-inch big-block crank to fit the small-block. The motivation to was to build something different and see what could be done with the diesel block. I could have made a lot more power, but I knew the engine wasn’t going to end up in an all-out racecar,” he says.

The engine uses the 5.7 diesel block, bored .153-inch oversize to arrive at a final bore dimension of 4.210-inch. Hood has also equipped the block with old NASCAR splayed 4-bolt main caps for extra strength. A production steel Oldsmobile 425 big-block crankshaft has had the outer diameter cut down .375-inch to fit into the block. In addition, the crankshaft has been profiled, nitrided, and balanced. Eagle Specialty Products 6.250-inch forged-steel H-beam connecting rods use ARP 2000 bolts for retention.

A set of Ross custom flat-top pistons wear Total Seal 1/16, 1/16, 3/16 rings, and the engine bearings from Clevite with PolyDyn friction-reduction coating applied. The double-roller timing set is from Cloyes.

Induction is handled by a set of high-port cylinder heads and an intake from Wenzler Engineering – these are purpose-built cylinder heads for the Oldsmobile platform and have been cast from 356-T6 aluminum. The heads use standard valvetrain components and fit both the small- and big-block Olds engine. An adapter plate from Wenzler is required for use with the true big-block platform.

The street-oriented camshaft used here is a custom-grind flat-tappet design from Bullet Racing Cams, featuring .545-inch lift on the intake and .565-inch lift on the exhaust side, running on a 112 lobe separation angle. Duration figures mark out at 232 degrees on the intake and 239 degrees on the exhaust at .050-inch lift.

“This motor was pretty racy when I first built it, but I had to calm it down since we decided to put it into a street car. The cam we originally had in it was just too wild, and we would have needed a 5500 stall converter to make it work. We tamed it down with the camshaft change – now it has the street cam in it and it still makes over 500 horsepower,” says Hood.

In a continued attempt to be different, nearly every part on the engine has been powder-coated. The external surfaces of the heads, intake manifold, valve covers, oil pan, and front cover are all finished in a sweet metallic gold coating – both for appearance and resistance to the elements and stray fluids. ARP stainless fasteners have been used throughout. 

The engine has been set up to be able to run smoothly, without racecar-like tendencies. “I’ll be able to run the factory vacuum-assisted brakes, and the engine has a nice idle quality to it – there’s just a little bit of a musclecar sound. There’s even a distributor location that was plugged off when the engine was used as a diesel piece,” he says.

An interesting use of a long-forgotten engine platform. Although the only piece remaining from the diesel application is the block itself, it’s nice to see someone recycling the product and adapting it for current use,  instead of letting it rust away in a boneyard.