Mopar Engines West decided not to deck the block as much as they could have in order to preserve the deck's strength and leave room for future rebuilds. So the block's deck height ended up at 10.67 inches. The new compression height yielded a nice short piston, but not so short as to put the pin bore in the oil ring. The rod journals were undersized slightly to allow for aluminum rods, and the head was cut significantly, yielding a 44cc chamber.
 When it came time for rocker...  When it came time for rocker arms, a custom set of roller rockers were purchased from Cox Brothers in Columbus, Ohio. After they were installed, we found out the extra rocker arm ratio moved the pushrods closer to the block, requiring the engine be disassembled so pushrod clearance could be made. |  Here's a neat little tool...  Here's a neat little tool for you aspiring and experienced engine builders. Go to www.performancetrends.com, where they have this computer tool that lets you figure what your compression is. |  Well, here is the finished...  Well, here is the finished EFI intake, but will we see an increase in power? |
When all the math was done, the piston resides .020 inch down in the hole to allow for rod stretch since we are using aluminum rods. A steel head gasket was used, and the result is a 234-inch Slant Six with a 13.25:1 compression ratio using a flat-top piston and a 44cc chamber. What is not shown by any of the pictures is the weight savings of more than 100 grams per cylinder that was achieved. This will not affect the horsepower much, but it did allow the engine to rev quickly and go well beyond the typical 6,000-rpm limit of the Slant Six. The engine was singing happily at more than 6,500 rpm. The smaller journal size allows the use of 283 small-block Chevy bearings. This is important, because with aluminum rods you must use a dowel pin, and heavy-duty bearings for a 283 Chevy are easy to get. The wrist pin is also small-block Chevy measuring .927-inch. The piston rings are 1.5/1.5/4.0mm pieces used in the Honda Vtech engine. The rod bearings are Calico's coated CB745HD. The bearings are narrowed .040 inch on each side, chamfered, and coated with their CT-1 coating.
 With the engine all buttoned...  With the engine all buttoned up, we bolted it to the dyno. With the carbureted system on it, peak numbers were 300 hp at 5,750 rpm, and 293 lb-ft of torque at 5,000 rpm. But what if we ran an EFI setup? Would we get some better numbers? |  Before we could put EFI on...  Before we could put EFI on the Slant Six, we needed to modify a manifold to accept the injectors. We're certain the guys at Clifford added these bosses for nitrous, but MEW figures the EFI will fit just as easy. |  Controlling the EFI is this...  Controlling the EFI is this F.A.S.T. XFI module. |
The short-block assembly did require some special attention. The main bearings are coated Calico bearings 4M1419AL. Clearances were checked, and the crank was test fit in the block. A piston-and-rod assembly was then installed to see how close the connecting rods would come to the bottom of the cylinder bores during their rotation, and to check the deck height. This was when we found out how much the bores needed to be notched. We had already minimized the amount of notching required by making the rod end as small in diameter as possible. Notching the bores can be a touch-and-go process, because there's a cooling water passage close to the area needing clearanced. So after the rotating assembly stopped hitting everything, the crank was permanently installed. By the way, have your ever bought a rear main seal for your V-8 engine and wondered what those extra little angled pieces are for? Well, they are for a Slant Six. It turns out that the rear main seal for a big block and a Hemi is the same as the Slant Six.
Not only is the rear main seal the same, but the crankshaft snout is also the same as a big-block. So finding a high-performance SFI balancer took no more time than getting a 440 balancer. Of course, the timing marks on a big-block balancer are in a different place from that of a Slant Six, but we just made a new timing mark on the timing cover.