who has documented proof which 396 motors were425Hrsp in 1965?

Question

I would like to know why the particulair webbing is different on my 396

porqupine was started with the mystery motor 427 cid 1963 I do alos believe 425 hrs 396 was available feb 1965 Ialso believe that 1st run motors were two bolt blocks and also gear driven they would not have known cranks would need extra bolts to keep from walking from rpm changes until used on actual circle track racing also 1rst rectangle ports were 208 rectangles butone must ponder the Idea that air travels better through a circle than a square! so I ask where do you find it written in stone which motor is the correct425 hrs 396?

Answer 1

The 396/425 was Corvette engine option RPO L78. I'm not sure what the first guys answer is supposed to mean. All big blocks have splayed valves. To identify a '65 L78, check the casting numbers. The block casting number should be 3855962, 4-bolt. The head casting numbers should be 3904391 for a '65. The heads are HI-PERF stamped rectangle port, 107 cc chamber, 2.06/1.72 valves.

The L78 was kept in production until 1970. GM changed the hp rating to 375 for the Camaros and Chevelles, but it was the exact same engine as the 425 version in the Vette. Kep in mind that post '66 L78's used various different casting numbers. It was also offered with the 425 hp rating in Bel Air's and Biscayne's basically as Super Stock cars.

Answer 2

Big block chevy motors. Common ones were 396, 402 (badged as a 396), 427 (My personal favorite) , 454 and now the 8.1 liter(496) Less common were 366 (trucks only) 502, 572 (marine and crate). Some big blocks actually have less cubic inches than the 400 small block but are larger externally and weigh about 200 lbs. more .The term "Rat" is only a pet name for this family of chevy engines and has nothing to do at all with induction or performance.

Answer 3

national auto museum the harrahs collection 10 s st reno nv 89502 775 333-9300 i believe that 65 66 67 68 ss chevelles were only made with 340 hp 396's. only about 1100 375hp 396's were sold each year. the RPO L88 427 inch big block corvette motors were the only engines made by Chevrolet with that much HP (425 and up) in 65-72 years. National Parts Depot (CHEVELLE PART) and Year One parts also have info. look in HOT ROD MAG for there address

Answer 4

The splayed-valve arrangement of the cylinder heads inspired the 'porcupine' nickname of the 1965 Chevrolet big-block 396 cid, 425 horsepower V8.

This engine was introduced in Corvette models mid-year 1965.

Answer 5

There is a covrette musuem in St Louis Missouri. Start there and they can direct you to a source.
Good question.