Sorry man but I believe you're thinking of the 1962 409/380HP, since it was the factory stock option until 1965 or 1966...the dual four barrel 1963 409/425 (dual 4barrel carbs) was a "special order" from 1964 to 1965...it may have been a dealer factory option, but it was not something granny could just drive off the lot unless the dealer already had one on the lot. It was replaced in mid 1965 by the 396/425 which is much rarer than the 409/425 because in the 1966 model year the bhp was dropped from 425bhp to 325/350/360/375bhp, depending on the vehicle. After that short run in 1965 the 396cid from the factory never exceeded 375bhp. You can look up the serial numbers.
I never realized that (409 = 4.312" x 3.50") vs (396 = 4.096" x 3.76")...a .26 increase in stroke made the engine slower considering the 396/425 4 bolt mains could handle higher rpms and reached peak hp at over 6200 rpm (409/425 peak hp @6200 rpm). Pretty sure the piston rods and the crank were lighter in the 396 than the 409, not the pistons.
If both of those cars had the original rear ends in them after you replaced the engine/transmission...you should have beat him, because I'm betting the gear ratio in your buddies car didn't match what was put into an original 396/425 Impala SS.
The 409/425 was an RPO. The Z-11 was the closest thing to a COPO car in that era. A Regular Production Option was not "special ordered", you merely placed an order. Any dealer could get as many as they wanted at any time. The 409/425 cars were found on the lot, I know at least a dozen people who drove up on the lot, found a 409/425 sitting there, and drove home with it. In 64, the 409 was a 340, a 409, or a 425. They are ALL factory stock, and regular production options, they had no restrictions, all were found regularly on dealer lots in stock across the country. My uncle sold them brand new, as a Chevrolet salesman from 1958 until he died in 1986. The man owned nearly every Chevrolet HP car built in that era except a Z-11, a ZL-1, or an L-88.
Of the 409 HP engines, the only one that had its production numbers actually limited was the 63 Z-11, which was actually a 427/430, not a 409, and had a 3.65" stroke and a 6.136" rod. That engine was a limited production option that you had to get through a factory race program, it came in a car with a complete aluminum front clip.
The two four barrel 409 was not available in 65, only the 409/409 single four barrel, but it had the big cam from the 64 409/409 and 409/425. It was only sold in the 65 in order to use up the production inventory, and once that was used up, they were no longer available. The two four barrel version was not offered, the intake and carburetor setups were kept as over the counter service replacement parts, as they did not want the 409/425 to overshadow the new 396/425 and 396/375 engines. That is the same reason the 67 Chevy II was not offered with the 327/350, Chevrolet did not want it to overshadow the new Camaro with the 295/350. The left over 327/350 engines from 67 were sold in 68 in Corvettes, but they had their aluminum high rise intakes and 565 Holley four barrels removed and replaced with low rise cast iron intakes and Rochester four barrels.
You are completely wrong about the 409 as compared to the 396. The piston in the 409 weighed close to 1000 grams, without the pin, where as the 396 piston with the pin weighed about 825 grams. The 409 rod is is lighter, it is about 0.100" shorter, and has a smaller journal bore. But the rod and piston assembly of the 396 is 159 grams lighter than the 409, and the fact that the piston is over 200 grams heavier on the 409 over stresses the smaller and lighter rods. The two four barrel 409/425 had a bigger cam and more available CFM, the heads flowed very well. In fact, the cam on the 409/425 had over 0.550" lift, where the 396/425 barely had 0.500" lift, and the 409 cam had more duration as well. Further, the 4.094" bore of the 396 is a serious handicap, as the bore shrouds the valves significantly. The 4.312" bore of the 409 unshrouds the valves far more than even a 4.250" bore 427 or 454. On top of that, the 409 has no combustion chamber in the head to shroud the valves either. The valves on the 409 are nearly even with the deck surface, and the extra 0.050"+ of valve lift only makes it better.
Even the 65 409/409 had a much bigger cam than the 396/425, the 409 had 0.557" lift on both valves, where the 396/425 had the same cam as the 396/375 of that year, with 0.497"/0.503" lift. The 396 did not even get a 0.520" lift cam until later, and that is all the cam a 396 EVER got. The 409 cam had more duration as well, about 15 degrees more at 0.050" tappet lift. The 396/425 was identical to the 396/375 in every way, except for the carburetor and intake. It had the same block, crank, rods, pistons, cam, and heads as a 396/375.
The later HP ratings on the 396 had nothing to do with the car they were in. The 325HP version had a low lift hydraulic cam, lower compression, oval port heads, and a low rise intake with a Rochester carburetor. The 350HP version was still hydraulic cammed, but with more lift, more compression, and a high rise intake, it still had oval port heads and a Rochester carburetor, the 360HP engines sold in 66 were essentialy the same as the later 350HP engine. The 375 engines had solid lift cams, most after 65 had 0.520" lift and 242 degrees duration at 0.050" tappet lift, even higher compression with forged high dome pistons, rectangle port heads, high rise aluminum intakes, and 780 vacuum secondary Holley carburetors. All of those engines were available in most any 66-69 Chevelle, Impala, or other mid size or full size model, even station wagons. They were also available in 67-69 Camaros, and 68-69 Novas. Until late 68, the 360 and 375 engines only came with a 4 speed manual transmission.
I have no need to look up any serial numbers. I've built and raced both engines for decades. I know them like the back of my hand. I had my first 409 almost 30 years ago, and I've had over a dozen big blocks from 396/325 up to 454/450 LS6 engines, and even had my hands on both an original ZL-1, and an L-88. I've even had an LS-7 454.
If you read the post, both cars had 4.56 gears. The 65 began life as a SS 327-300 4 speed car with 4.56 gears. My 64 began life as an SS 327 automatic car with a 3.08 gear. I bought 4 chunks for it when I bought the 409/425 from my cousin, it had been in his garage for some 14 years. It was pulled from a new car under warranty for rocker arm failure. I put the 4.56 posi chunk in my car for street use, and got a Muncie M-21 4 speed (actually, it had several in it) with a Hurst shifter.
