Steve Baur
Former Editor, Modified Mustangs & Fords
June 1, 2007
Contributers: Tom Naegele Photos By: Courtesy of D.S.S. Racing, Ford Racing Performance Parts
The Boss has finish align-honed lifter bores-R blocks must be align-honed, as the bores are small out of the box. The Boss' big lifter bosses allow machining for offset or bigger lifters. They will, however, need to be machined down to use the factory lifter spider bar.

D.S.S. Block Blueprinting
"People often toss around the term blueprinting, but few understand it," Naegele continues. "Our new horizontal machining center was purchased because of the need and desire to CNC blueprint a block more accurately than was previously possible. Blueprinting is remachining the critical dimensions and geometry to correct it based on factory specs.

"The crankshaft main centerline is pretty much ground zero, and cylinders should be 90 degrees apart and equidistant from the crank and camshaft centerlines-each bank should be 45 degrees from the centerline. Another important part of blueprinting is ensuring the deck surfaces are perpendicular to the cylinder bore, which should be directly located over the crankshaft and parallel to the 90-degree centerline.

"From the factory, OEMs just need blocks to have similar compression between cylinders. The closer you get to a perfectly machined product, the better it will run and the longer it will last. Because of the slack in factory tolerances, compression from bank to bank will be different. D.S.S. has seen a minimum of 0.005 inch difference, and as bad as 0.025. The OEM engines just need to run and last through the warranty period; however, setting deck height and ensuring it is equidistant from the crank centerline is extremely important to get the most out of your motor.

"Many places use the Sunnen CV616 or CK10, as they're the industry standards and are designed to hone 0.030 over without boring the cylinder. If you do not bore the cylinder and then hone it, you are not correcting the cylinder; you're just averaging the wear and not straightening out the cylinder. You are also moving the cylinder over in the direction of wear. It'll run fine, but that's the difference between average and truly blueprinted.

"Honing cylinders with torque plates is also an important part of blueprinting. A lot of CNC equipment fixtures off the oil-pan rail, which is how Ford machines its blocks, but it's not the main bore and not a good reference point. The fixture that D.S.S. manufactured to do its CNC work is the only one of its kind, and it allows us to blueprint off of the mains instead of the oil-pan rail.

"Oddly enough most aftermarket automotive CNC and conventional machines mimic the same OEM set up off of the oil pan rail. Also, most bore off of the OEM cylinder and true the decks using a bubble level. For Joe Average, that's OK, but it should be perpendicular. Most boring machines go off of the deck surface, so if it isn't perpen-dicular, then cylinder bores won't be exactly 90 degrees from the crank.

Since the new Boss 302 block uses larger 1/2-inch main-cap bolts, a different oil-pump pickup was needed, and FRPP has you hooked up. Part number M-6622-Boss302 is what you need to fit the typical Fox stamped-steel pan.

"All of Level 10 and 20 CNC blocks are blueprinted off of the mains, something D.S.S. has been doing for the last five years. We invested heavily in this method, and though it's more profitable to do it the old-fashioned way, this is the right way to do it. Holding a block rigid enough to machine within a tenth or two vertically off of the main centerline is not easy (or cheap), but the countless hours of CAD design and machining paid off. This is by far the most accurate, rigid block fixture and machine we have ever seen.

"Why is that so important? Here's an example. Camshafts are ground with lobes 90 degrees apart, but what if your block was 89 or 91 degrees? What if your compression ratio was three or four tenths of a point different side to side or even front to back? Of course it will run, but it won't be optimized, and in a high-performance application, getting the most from what you have is of the utmost importance. Our Level 20 CNC blueprinting on the Boss block also includes the required lifter boss relieving so the factor lifter retaining hardware can be used.

"Twenty-five years of racing and honing thousands of blocks has taught us plenty about the importance of ring seal and cylinder prep. The three-step honing process we developed is done on all of our Level 10 and 20 blocks. These steps are pivotal to our customers' success."

Large and In Charge
Thanks to FRPP and D.S.S. Racing, Stolen Goods is in good hands. Our new Boss 347 should give us plenty of go-fast grunt to make mincemeat of the '93 R model, among others. Next month, we plan to have the short-block complete and detail the rotating assembly, along with some of the long-block parts like the heads, cam, and intake manifold. See you then.