In my mind, massaged is different than outright substitution (427 in for a 396) – one is playing the game and the other is fraud.

 

Agree, it's certainly different...but fraud?

 

Heck, who would not want a good sonic tested 427 standard bore block? Who cares if it was a 396 to start with. Being an early block which cam bearing set up does this engine have?

Now once this engine is in a car sitting at a car show and some 396 expert comes up and points out it is actually a 396, say, YEP, want to race! HA, have to have some fun with it.

 

Makes you think of the line from the old Twin Peaks show - "The owls are not what they seem". And neither is this block!

 

Pretty unlikely. Pontiac was only decisively outed on the 421 GTO when Jim Wagner confessed. I’m not sure who his counterpart in Chevrolet would be or if he is even around. Maybe Ed Cole or Pete Estes. Pontiac got caught up in a car enthusiast controversy with the GTO title and felt they should defend its use by challenging the Europeans in some flaky competition thru Car & Driver so they loaded the dice with the 421. The Chevy SS series had no such controversy or publicity campaign to defend.

 

it will NEED the grove in the rear of the cam with the matching grooved bearing

 

the amount of discussion in this thread is starting to remind me of the old trim tag replacement thread from 2019...

 

It was both. I think it was a 2-inch fuel line that was 11-feet long. It held 5 gallons of gas.

 

And it was hidden inside the frame rail.

 

IF my math is right: 2" pipe radius is 1 inch. 11 feet is 132 inches. Volume is pi x radius squared x height (or length). So 3.1415 x 1 x 1 x 132 = 414.7 Cubic inches.

1 US gallon is 213 cu in.

So about 1.79 gallons extra, which is still a big help, can get you several extra laps depending on the track and consumption rate.

 

Double post

 

1) Tonawanda forged and machined the engine blocks, and then assembled them.

because of the “962” casting they would not have bored it to “427”, but even if GM did, it would still appear to be a bored-out 396 because the “962” block was designed and cast to be a 396.

2)Fremont assembly plant did not put in orders for bare blocks. They put in orders for fully assembled engines. The “1007EJ” was stamped at Tonawanda, and indicated the engine ( long block) had the specified parts for a 360hp/manual transmission with A.I.R. ( California K19 smog).

3) the “Z08727” stamping was NEVER stamped by/at Tonawanda. That stamp, which should read “Z108727”, was stamped AT Fremont on the vehicle assembly line to correspond to a specific Chevelle on the same assembly line.

4). As noted, Fremont did not use bare blocks, and did not assemble engines.

and Tonawanda, if a mistake was made, would have stamped the correct coding over the previous. Of course, the 962 block would not have been used for a 427.

So you believe two mistakes were made.

Measurements will only confirm what it is now. Not what it originally was.

and regardless of what you think was the original size, it will always be a “396 block”, regardless of having a alleged “virgin” 427 bore….

otherwise, why did Chevrolet use different casting numbers for 396 and 427? Chevrolet knew there was a potential overheating issue with the 961/962 blocks bored to 427 specs. GM would not have risked the possible warranty issues.

Not worthless, but not worth as much as another 962 with less overbore.

FWIW, I have run several 962 and even a 961 2-bolt block with a 427 bore. Usually not an issue if sonic checked first.


BTW, ever ( or almost every ) 396/car427 has the “ Hi Perf” casting text. I run into a lot of people that think it’s special because it says “ Hi Perf”

 

From what I've been able to piece together, the 961 and 962 used different patterns for the water jackets, the 962 had a larger OD on the cylinder. The 427 blocks used that same water jacket pattern, but used a larger pattern for the inside of the bores, so they didn't have to bore as much to bring it to 4.25" bore.

This is related to how the patterns were used to make the casting mold. There are several patterns that were used to make molds for different applications, and they seem to have been marked for all these applications. So you'll see HI PERF, PASS and TRUCK on these parts of the block, but only one or two marks on places where the pattern was more specialized, such as seeing HI PERF on the top of a rectangular port head.

Is there a detailed description somewhere of the foundry process that was used to make these parts? If so, it might explain why things are the way they are

 

Hi perf pass was used on blocks for passenger car cars, Chevelle, full size cars, Camaros, Novas, Corvette and select pick up trucks. The blocks with truck embossed on them were the tall deck 366 and 427 versions. The biggest difference between 961 and 962 where 961 where 2 bolt main and 962 where 4 bolt.

 

Hmmm...doesn't really match up with what I've seen.

I'm still interested in knowing how the casting process works.