A regular GM code is a 215 from 63. A a JN code is the higher compression version. The good thing is that the regular 215 run well on lower octane fuel compared to the high comp versions. How does yours run?
The pictured engine (code) is from a motor and trans I purchased several years ago. Not sure how it runs. I bought it because my 63 Skylark's 215 engine is in pieces, and I decided it might be a good idea to have a spare. The original skylark engine had a 4 barrel, so I might assume it was the high compression motor ?
I have been told and read that there were both 4bb low and high compression 215s in 63. http://www.britishv8.org/Articles/GM-215-Engine-Identification.htm
OK, who wants to take a stab at this one? I was told it was a Buick 215, but the heads and pistons are definitely Olds. It came with a 4 bbl intake, but I set this one on it. Jim
High compression Buick 63 215, it was about 11:1 ratio however with the olds heads that have larger chambers it should be about 10:1. There is more detail about all this in my upcoming book about SBB performance.
Where exactly is the JN code? I’m lost on the picture of the stamping and I’m trying to explain on the phone to a seller. The only numbers I have are the production 3J1548264. Which tells me that it’s a 1963 built in Michigan. The motor is a 4 barrel but it could have been change out. Is the JN stamp close to the above production numbers? Thanks for any help, Barry
You have to go by the head casting number. There were two high compression heads: the 4bbl head and the Jetfire head. They were essentially the same chamber size. I do not recall the numbers but hopefully someone here will know. Unlike Buick who used different piston dishes with the same heads, Olds used the same pistons with different heads to get different compression ratios. The Olds high compression heads had the same chamber volume as the Buick heads. If you use low compression Olds heads with low compression Buick pistons (the only 215 pistons available for awhile) the CR drops to probably somewhere around 6.5 and it'll still run and even produce good torque, but HP will be down and mileage will be poor. Jim
