65 396

[Walter F.]

What made the 65 396 with 425 H.P. so different then the version offered in the SS396 Camero and Chevelle? What was the difference between the 66 427 with 425 horsepower and the 427 with 450 horsepower? Both engine according the the black book cost the same.

[Bill W.]

Re: 65 396

Walter , I cant answer the 66 part of the question but the "65" 396 and the Camaros & Chevelles with a 396 both had engines with 396 cubic inches . That is about the only thing that is the same . They had different blocks (the Corvette was heavier duty ) Carbs & intakes were different . The heads were different . The Corvette had a little bigger cam . Forged pistons & rods . A cross drilled forged crank . A lightweight flywheel ,cast iron pulleys 8" damper etc. The 65 396 to me was almost like a practice L88 . I dont know if its true but I have always heard that a real 65 396 would dyno at more than 425 HP . Im sure other people will answer the 66 part and add to the 65 part . Bill

[Keith B.]

Re: 65 396

The 65-66 Chevelle SS 396 solid lifter engines used the same block and heads as the 65 Corvette 396. I think the diffreance in HP is due to the exhaust manifolds and just plain GM advertising hype

[Roger W.]

Re: 65 396

I remember reading some place that the Auto insurance companies were starting to complain about the high horse power cars. Chevrolet lowered the HP rating from 450 to 425 about the middle of the 66 model year. There were no physical changes to the 427.

[Bill W.]

Re: 65 396

Keith Im not sure about the 65 Chevelle heads but the 66 used a different casting number so there must have been some difference . Even the 962 4 bolt block used on the 66 375 hp Chevelle was different , it did not have the ribs on the front & back of the block . I never understood why they would remove the ribs on a 66 962 and still have the large oil fitting hole & 4 bolt main but not change the casting number ????

[Tom D.]

Re: 65 396

Which had the thicker cylinder walls?

[Joe L.]

Re: 65 396

What made the 65 396 with 425 H.P. so different then the version offered in the SS396 Camero and Chevelle? What was the difference between the 66 427 with 425 horsepower and the 427 with 450 horsepower? Both engine according the the black book cost the same.

Walter------


The 1965 Chevelle with 396 375 HP was equipped with an hydraulic camshaft of GM #3873844, the only use of this camshaft. Otherwise, it was similar to the Corvette L-78 except for exhaust manifolds.

The 1966 427 450 HP and 425 HP were identical engines. Only the decals were different.

[Bill W.]

Re: 65 396

Tom the 65 962 block with the ribs or gussets had the thick walls . I dont know about the late 962 Chevelle block without the ribs . Bill

[Joe L.]

Re: 65 396

Tom the 65 962 block with the ribs or gussets had the thick walls . I dont know about the late 962 Chevelle block without the ribs . Bill

Bill-------


Some folks might think that "thick walls" implies a good thing. It doesn't. Too much cylinder wall thickness interferes with engine cooling. That's why GM almost always revised block castings when the basic block was going to be used for a larger bore size.

[Larry E.]

Re: 65 396

IIRC: When Chevrolet came out with the L78 rated at 375HP in their Camaro's/Chevelles/Nova's is did not fool NHRA very long. In the S/S class
that engine was "refactored" into 425HP in a very short time. Larry

[Wayne M.]

Re: 65 396

Tom the 65 962 block with the ribs or gussets had the thick walls . I dont know about the late 962 Chevelle block without the ribs . Bill

Bill -- not so sure about that. Here's my "961" 2-bolt block, cast E_14_5, and it has the gussets, and (in a previous discussion on the DB), since I could barely slip a pencil between the castings in the water jacket, (through a freeze-plug hole) this meant thin walls.



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[Bill W.]

Re: 65 396

Wayne , I dont know much about the 961s other than they had ribs . What was the cast date on it ? And what was it used in when new ? I dont know what the cylinder thickness is on the non ribbed 962s . I have a ribbed and a non ribbed 962 both have been bored to 427 and then 60 both were blower motors and now both have 1 cracked cylinder .

[Paul D.]

Re: 65 396

I seem to recall reading somewhere that the orders to lower the HP rating came from within GM, although possibly to appease the insurance companies. The story alluded to a "rule" or agreement within GM to not have HP numbers exceeding cubic inches. Hopefully, someone on the board can elaborate. Chip.

[Wayne M.]

Re: 65 396

Wayne , I dont know much about the 961s other than they had ribs . What was the cast date on it ? And what was it used in when new ? .

Bill --- block cast date is May 15th 1965; pad assy. stamping is T0607LP, which is June 7th, 396/325hp with manual trans. Have no idea what car it was originally installed in.

[Keith B.]

Re: 65 396

Wayne that engine would have came out of a full size Chevy