The block decks are machined to achieve perfect cylinder-head mating surfaces. Peart makes two passes on each side and shaves 0.010 inch off the decks. We couldn't help but notice the previous machine shop never cut the decks. | 
One pass of the milling machine shows this irregularity--deck warpage. One more pass will eliminate irregularities. Doesn't this tell you something about why cylinder-head gaskets blow on fresh engines because someone didn't check and mill the decks? Light areas are low spots--areas where coolant and/or compression could leak through. | 
Because our 390 block is already bored 0.030 inch oversize, we didn't bore to 0.040 inch over. Instead, we'll hone the additional 0.010 inch. We do this because boring creates excessive heat we don't want. We'll take a slower path to 0.040 inch over. JGM begins with coarse stones, then finer as he hones. Here, he tapers cylinder bores for smoother access. |
Why Use a Torque Plate?
Even though an engine block looks like a big, invincible chunk of machined iron, it's sensitive to virtually everything, including heat and stress. Install and torque a pair of cylinder heads and your block "moves" to that shape and union. Think about it--when you torque cylinder heads, you're "moving" bolt holes, decks, and cylinder bores. These elements change shape and dimension. We fire the engine and they change yet again with heat.
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Connecting rods are reconditioned the same way we line-hone. Peart disassembles each rod and removes the rod bolts. He shaves the caps first, and then hones large ends as shown. This gives rod bearings a nice crosshatch pattern to hang onto. The large end, if reconditioned properly, should have a crosshatch pattern and provide adequate bearing crush. New ARP bolts are installed in each rod before honing. | 
Summit Racing Equipment provided us with new Speed-Pro 0.040-inch oversize forged-aluminum pistons with coated skirts for reduced friction. These C3AE reconditioned Ford rods offer plenty of strength for our 390 street engine and will take a six-grand blast. Rods are bushed for floating pins. |
When your machine shop finish-hones cylinder bores, they must be the same shape they would be with the cylinder heads torqued in place. That's why reputable machine shops use torque plates that are torqued to specs for honing operations. This allows the cylinders and block to conform to the installed shape. Savvy machinists also understand there needs to be a cooldown period between honing phases because honing generates heat, which alters cylinder dimensions. Jim Grubbs hones a little, then checks dimensions top, center, and bottom before and after cool down.
Oiling-System Improvements
Even if you're building a stone-stocker, you should always be thinking about oiling-system improvements. All oil passages should be chamfered to reduce fluid turbulence and improve flow. Pressure is important, however volume is more important to not only lubrication, but also to heat transfer. Did you know oil does more than just lubricate? It also carries heat away from hot engine parts. Improving return oil flow to the pan is just as important. Chamfer oil-return holes and use red GE Glyptal paint in all oil flow areas--valley, heads, timing set region in front, even the inside of your oil pan. Before application of GE Glyptal, surfaces must be hospital clean or it will peel off. You can find GE Glyptal at Eastwood.