There is only one real area of weakness in racing these Mopar flat head sixes. That is the oiling system. Here are some opinions from a life time of engine building. In the beginning, the oil pick up tube is a loose fit in the connection to the feed elbow. If you put a neopreme o-ring or two on the pipe before inserting it into the elbow, you will get a lot better feed of oil and less cavitation from air being sucked into the oil pump at this connection. Next make sure you use the later model geo-rotor oil pump. No oil pump is a good pump unless it is a brand new pump. When the block is toren down, remove all oil galley plugs and polish all oil passages. Do the same on the cooling system areas as best you can. I use a gun cleaning kit with a drill motor and the brass brushes of different calibors. Be sure to flush and blow clean after polishing. Include the crankshaft oil holes from mains to rods as well. The cam bearings only need a small amount of oil but have large oil feed holes. Federal-Mogul amd TRW used to sell oil flow restrictors for the four oil gallies going to the cam bearings. You can do the same thing by drilling and smoothing a 1/16 Dia, hole in the bearing and turning the bearing in the block so that the new 1/16 hole lines up with the oil galley in the block. There is a lot of oil pressure lost with the large original holes in the bearing. Also just lightly polish the bearing mounting holes in the block with a brake cly. hone and clean before installing the cam bearings. Caution: DO NOT OVER DO THIS. If you see bright, shiney metal after you are done you went too far. It only takes about one or two seconds of honing with cleaning solvent to clean this hole. Do this before you flush and clean the oil galleys. Next use full groove main bearings. Most suppliers sell these now as stock replacement bearings. The original main bearings only allowed oil to the rod bearings on the bottom side of the rod journal rotation. Block off the oil squirt holes in the con rods. These supply oil to the cylinders but with the full groove main bearings, you will get plenty of oil throw off from the side clearance of the rod bearings to oil the cylinders and cam lobes. Some times, you can just install the rod bearing upside down in the rod to block off this hole. This oil hole supplies an oil leak from the bearing to crankshaft area at TDC, just when you need the oil to protect the bearing. Difinitely replace the piston pin bushings and recon all the con rods. If possible, have this done by someone who can bore all six rods center to center the same. If you are only racing this engine, remove and block off the oil filter and feed lines. The filter is only a partical-flow and as so , it only filters a small amout of oil that is returned to the sump. Eliminating this internal oil leak insures more oil to the engine. Note: If you do this, change your oil often while it is HOT. Using your gasket as a guide, make sure the intake and exhaust passeges line up between the maniflod and block. Blend these with a light grinding if nessecary. Be sure to replace the water distribution tube that is in the block behind the water pump. Have your block and cly. head surfaced on a rotory broach machine. ( Strom-Vulcan Block Master ) This creates a rough surface that helps hold the head gasket in place and improves the sealing ability. You may already know some of this and I encourage you to consult your machinest/mechanic before doing any of these things. I have built these engines for many different applications and have never had any of them go bad but to each his own. Good Mopar Luck to you. Garry
