Along about 1970 they bored them out to 402 but still called them a 396 in cars,pickup trucks had the 402 but badged as a 400 which is confusing since there was also a small block 400. That number also shows a 454 and could be either 2 or 4 bolt mains.
That block is apparently 1969-1972.

39698541969-72396/402 /454

 

Intake manifold numbers are for a 325hp 396 oval port.
3883948 1966-68 396 325 L-35

 

 

Actually as much as 425hp,that was a one year only Corvette engine though. 1965 was the first year big block Corvette and you could get the 425hp/396 that year,1966 it was enlarged to a 427 in all big block Corvettes.
The difference had to do with intake and carb combos (cast iron with a q-jet or aluminum hi-rise with a Holley), different cams some hydraulic some big lumpy solid lifters, some of the higher performance engines had higher compression ratio pistons and cylinder heads that were different even a few with aluminum heads,they also had forged steel cranks and rods with 4 bolt main bearings etc. etc.

 

The factory and insurance companys were butting heads back then. The 425 hp 396 lost 50 hp with the same engine in later years. How? The 425 hp rating was at a higher RPM. The 375 hp was about 800 less RPMs. In 1965 there was also a 396 with 375hp in the Z16 Chevelle (201 built). Different internals (hyd. cam) in that engine.

 

I'm also looking for a L78 396 and had a question in regards to "matching numbers". After some research I'm finding out that the block can actually be restamped. Does anyone have pics of a block that is stamped regardless of engine size. The "matching numbers" I've seen on some blocks are not all lined up like numbers on other parts. Just want to see if there is a difference so it will be harder for me to get taken.

Thank you

 

Good day everyone,
First off I’d like to thank all of you who took the time to respond and also provided great information.
Well my engine search is still ongoing. I’m now considering purchasing a 454 cic motor. Seems to me that they are more available than a 396 and priced about the same with some even being cheaper.
I’ll keep you all posted with what I come up with.

Thanks again,

 

If you go 454, there are 2 different deck heights, 9.80 and 10.20. The 396 is a 9.80 block, so stay with that deck height, it makes stock stuff fit your application.

 

That's because the 396 hasn't been made for many years,454's were in a lot of trucks for many years after the last 396's were made and for years after the last big block cars with 454's which was mid 1970's. Pickups Suburbans and motorhomes had the old MK IV version up 'till about 1990 so there's still a lot of them out there.