Just a 5 cubic inch difference between the two. Not sure how to tell them apart but most likely nothing to worry about. I am guessing that the crankshaft will be the deciding factor between the two engines. Most things you will be replacing should interchange easily.
BTW my information shows that the 1962 Impala came with the 235, not the 230 engine. http://www.impalaforums.com/resource...58-2011-a.html
This is part of the text from the article:
In 1962 the option of the Super Sport was available on only the two-door coupe and convertible. However, the SS models in 1962 could have any engine from the standard 235 ci six to the 409 big block V-8. (Impala SS engine options included the 235ci 135hp I-6, 283ci 170hp V-8, 327ci 250 V-8, 327ci 300 V-8, 409ci 380hp V-8 and the 409ci 409hp V-8.) Horsepower ratings on the 409 ci V-8’s were upped to 380 on the single four barrel and 409 on the 2 x 4 barrel. The heavy duty mechanical items of the 1961 Super Sport option (HD springs, shocks, brake linings, etc.) were deleted in 1962, though they were available optionally. Chevrolet increased production of the 409 and made it available in all full size Chevy's - Biscaynes, Bel Airs, and Impalas. The Impala Sport Coupe came with a ribbed rear roof line and a smaller back window to mimic the look of a cloth convertible top. The Impala's were a bit less aerodynamic this year, which made some racers turn to the lighter and slicker Bel Air coupe. The biggest change from 1961 was that the front bucket seats with a short console between became a part of the SS package in 1962. On the exterior, the most noticeable difference between the Super Sport Impala and the regular Impala was the use of aluminum body molding inserts; plain Impalas came with painted inserts. The rear fender SS emblems were redesigned. For 1962 the SS letters with red inlay were positioned over the circular Impala emblem. An Impala SS emblem was located on the right rear part of the trunk. The 409 was improved by adding new cylinder heads and a revised camshaft. With the standard 4 bbl carb, the 409 produced 380 bhp. But the real news was the improved top of the line 409 which added a pair of Carter AFB four barrel carbs and a lightweight valve train, and produced an astonishing 409 bhp, or a magical 1 bhp per cid. The 409 legend grew. Prices ranged from $2,961-$3,925. Weights were approximately 3,450-3,920 lbs.
1977 Chevrolet Impala Sedan, 305, TH200, 2.56:1, 111K miles, 37 Lifetime Warranty Parts.
1989 GMC C1500 Sierra ECSB 350, HM290, 3.08:1, 344K miles, 23 Lifetime Warranty Parts.