I have a 426 wedge at the machine shop. Another guy doing my heads. Got a call from the guy doing the heads. He ask if it was a reverse rotation engine. I ask if it mattered. He said if it was reverse rotation the nerling on the crank main seal area was the opposite direction it should be. If the crank was run the normal way it would pump oil. The pad near the distributor that is not on a 440 has B 426 stamped on it. It also has 4.25 bore and flat top pistons. The heads have 2.08 intakes and 1.60 exhausts. Getting hardened seats and bigger exhaust valves. After thinking about the marine question it may well have been a marine engine. The ports to and from the water pump have had rust damage. They aren't round from rust damage so I don't know what I have.
I've ran into this before (although not on a mopar) and I doubt it will make any difference. If it really bothers you, have the knurling polished down. The case I saw the boat owner was told in the course of an overhaul that he needed a 'special' rear seal because of the 'reverse' knurling, turned out that the knurling was standard and the hi-buck 'special' seal was OEM repackaged at 10X the price... lol. This motor had been running reverse-rotation, without a rear main leak.
Another clue for a R R would be the piston pin offset , although Chrysler marine doesn't seem to think it is of any importance. A friend and mentor freshened a pair of LA style 360's that had taken a bath n fresh water and other than a reverse grind cam, no other mods were made.
I used to dabble in these engines and I am confused by the description of your engine. "The pad near the distributor that is not on a 440 has B 426 stamped on it." That same pad is on all raised block Mopars- 413-426-440. Why would the cylinder head machinist be concerned about rotation? Can your crank grinder figure out he proper direction of the main seal knurling?
A 426 marine engine is stamped 426 M. It is a very good block. Just because it is marine doesn't men it is reversed. Only on dual engine boats and then only one engine. I have done several of these over the last 40+ years. I prefer to use the 440 crank and rods. That said when the crank is rotating in the block in the proper direction is the knurling pushing the oil back into the engine of shoving it out? It is true you may be able to get away with it even if it is wrong however why take that chance? When I am inside a motor , mine or a customers (when I was in the business) I never take chances at something that can cause trouble. Check and make sure. You only want to do this once. BTW My 63 MAX wedge is actually a 426 Marine block. I set up and machined the Stage III dual valve reliefs for the cylinder bores when I built it. It all started when I found a set of STGEIII 426 Max Wedge heads for sale. Pistons are a real pain to find. Mazolini used to keep sets of custom made JE Sportsman forged in stock which he had made in batches. That is where I got the ones for this motor. Otherwise you can bore to stock 440 bore which is 070 over. The block wont even feel that. Have done it three times in the past. don
Back in the "day", we did have a problem with reverse knurling and rear main seal leakage. The pad stamping, B426 would denote a 1966 426 which could only be industrial or marine. A426 is a 1965 426 street wedge and the last street wedge. In 1964, the street wedge was V42, the max wedge was VMP-426. In 1963, the street wedge was T42, the max wedge was TMP-426. What are the casting numbers and casting date on your block? Don Carns, AKA Dodgeboy
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