My uncle, Chris werner, who had the record setting N/A V6 regal...(Kenny Duttweilers old red regal..Chris ended up selling it to that cop...Billy Chaffin?), ran 9600rpm through the traps with 600hp on a CAST crank. He kept breaking forged nascar cranks and ended up going with an intelligently prepped cast crank. That crank never broke. If you know what you're doing, the cast crank is fine. I would drill out the oil galleys and do all the other possible oiling mods, (open up all the return holes and polish all the casting flash out of the block. This not only helps the oil get back to the pan faster, but it also greatly reduces the number of stress concentration points in the block where cracks start. Have a crank ground by someone who knows how to make a serious crankshaft (i'd recommend Howard Allen at JMS racing engines in monrovia, Ca.), and run an RJC main girdle and Eagle rods.....full floating setup on the wrist pins and some CP or JE pistons. Dont go too big on the piston to wall clearance if you plan on running the engine cool (160 thermostat) .003" absolute max. I would shoot for closer to .002". I honestly dont think steel caps are necessary if you run a kickass girdle like RJC's. Problem with the steel caps is that the metal is so much harder than the cast iron, that when you do the line hone, the honing bar resists removing material from the caps, and wants to drift into the block. You can end up with the crank and cam being too close together, and this will drastically reduce the number of line hones the block will take...plus another downside to that is that it moves the pistons further up the hole. I HATED doing steel cap conversions. Theres a boring jig that has to be bolted to the block, and the caps come undersize so they have to be bored out ALOT before they can be honed. Then the material is so hard that it makes doing a proper line hone a PITA. Find a shop that has a square decking jig. Go with a zero deck..a true SQUARE deck (great for quench which is real important on a force fed motor), and line hone with the heads torqued down on the block. Also use a torque plate to hone the cylinders (after the line hone) and run total seal rings if possible...you want that quench. If you want a truly blueprinted motor, you have to do it all in the right sequence. Do all the oiling mods first. Then line hone with heads torqued on the block. This gives a true position for the deck squaring jig to locate on. Then do the squaring and zeroing of the deck. Then Bore and hone with torque plates. Ive seen alot of old school block decks, crooked about .020-.030" Really terrible. If the head bolts arent perpendicular to the deck (which is the case with a crooked deck), then the head can creep after the bolts get torqued. Then you lose the seal. Of course you also end up with inconsistent preload on the lifters and varying quench from cylinder to cylinder among other things. A quality blueprinting job on a block is far more important than people think on any motor. You can free up ALOT of power doing a proper blueprinting job cause you're reducing all the parasitic frictional losses between the proper honing jobs and getting the exact same dynamic compression in every cylinder. Most of these old blocks are screwed up from being machined at the factory with worn out old gang tooling machines. Its not uncommon to gain 40-50hp and gain alot of mileage just from doing the block right. Also, next to detonation, nothing will break a main cap like poor alignment. Dont skimp on the line hone and make sure the line hone is done with the girdle in place and torqued.
