Thread: 305 pushin 480HP?

Tweet

I accually found out that 010 = 1% tin and 020 = 2% nickel. I have a 3970010 and the numbers 010 under and to the right of the timing chain cover indicate that it contains 10% tin that makes for a good casting as it allows the metal to flow adaquately and the nickel adds strength. I just recieved this information from a trustworthy source. Thanks for the craigs listing I'll check on that tommarow. Will I have to have work done on the lifter cyinders if I decide on a roller cam?

I don't think that's quite correct: almost all blocks you'll find to be in really good shape today will have "010" under the timing cover. If they haven't they're probably junk already. 010 means 1% nickel, 020 means 2% nickel. 010/020 means 1% tin, 2% nickel. The tin allows for better flowing and the iron will fill the mold better. Nickel adds hardness, so wear will be lower, especially on the cylinder walls. But nickel also makes for a more brittle block, so when power is going to go into the region where the block flexes noticeably, high nickel isn't an option. If you're thinking of doing a lot of drilling or grinding work on the block (oil galleys, boring, splayed caps, clearancing) remember: nickel is a tool killer. Some Motown blocks have as much as 5% nickel in them, but along with other additives to counteract the brittleness and there's no need to detail them.
If you're going for serious horsepower and longivity, go aftermarket. But up to 500hp you should be OK with a 1% nickel block, best bet would be to sonic test cylinder walls for equal thickness all round and put on splayed main caps. Then you're OK and cheap.
As I said, that is my information, without guarantee of correctness.
Max