O.K. Here's one for all you detail buffs. I recently bought a fishisned pro street 67 with a BB. By all accounts it oiginaly a 454 that came out of a 70 Corvette. The block deck appears to have been angled milled so the only numbers that I can make out on the right deck are the last 4 which are 3155. These could be from the machine shop stamp however. On the machined boss on the block directly centered above the timing cover is 104239XN. I tried to look at the numbers on the block behind the cylinder head however the engine has been set back and there is no way to have a look unless I would use a borescope and wouldn't you know it I just sold my last one. OK the last part was a joke.

Anyone that can enlighten me on the engines origin will be King of the Camaros for the next week.

 

The "XN" code stands for: 1968 396, 275 h.p., 2 barrel carb, Truck engine

 

After Camaro 69's reply, which was 100% correct based on the provided info I contacted the seller of my car and tore a trip off him regarding the engine not being what it was supposed to be. He swore up and down that it was indeed a .090 over 454, 4 bolt block.

I dug deeper, popped a valve cover and the casting # on the heads, 336781 did indicate that the heads were open chamber 454 heads. I then got my small digital camera down by the firewall on the drivers side and took several pictures to try to get a casting number off the block and there it was 361959, 454 block it is. Took off a cylinder head and measured the bore and it indeed was 4.340 bore with what appears to be accurate and the domes on the pistons do appear to be right for the 12.5 motor it is supposed to be.

Moral of the story, don't go by the stamped numbers but use the factory casting numbers to identify and engine. Stamped numbers can be altered, changed or be inaccurate.

Happy once again.

 

454 with casting #361959 was made between 1973 and 1985, and the heads casting # 336781 were also made between 1973 and 1985. are you sure about 9XN code,
9XN 1979 Marine 454 245 LF-8
9XN 1989 Marine 454 310 L-19 2 bolt Inboard.
2 bolt main from factory , someone could have had 4 bolt main caps installed .

 

That's different, now that we know we're looking at a 9XN 454 and not an XN 396. It's always best to get as many numbers off a block so you can cross-reference. Casting numbers alone don't always tell the story since some castings were used to build more than one size engine. At least you know what you have now. Your block casting was used for the Chevelle, Passenger car, and Truck. But the 9XN suffix code does show the block to be used as a marine build as mcmahon stated. And by the numbers, those head castings most likely are matched to the block. If the block was out of a Corvette, it would have casting series 39xxxxx.

 

Yea Camaro 69 , more numbers , easier to figure out what it is .