High-Nickel SBC Chevy blocks?

[ss wannabee]

Having an argument with a friend. I always thought that they were only available in the Chevy Performance Catalog...usually as a Bowtie block or something like that.

He says that some production-line blocks were high-nickel as well. Never heard of this...checked online...and the banter goes on and on...

Need the straight scoop..First WHAT is a high-nickel block? Isn't it really the percentage of (tin) in the cast-iron slurry at the foundry? Could the Bowtie or similar performance-catalog blocks have percentages of 10% or more?

Did regular cast blocks have a small percentage...(maybe 1, 2, or 3 %) anyway...and did GM adjust this... as needed...for production-line performance or Truck applications?

You machinists out there probably know...I hear these "hard" blocks are tough on cutting bits and stones....

[randy wilson]

Yes, there are high nickel content factory produced blocks. I believe they say 10 stamped on them somewhere. They'll correct me if I'm wrong. And possibly the 509 block. Someone else help out here.,

[Michael Kilduff]

I was thinking heat treating or cooling times/rates determines the hardness and that the '010' and '010/020' were different molds. But not sure. Discussed this in a Chemistry class with a grad student that was very familiar with metalurgy over 25 years ago.

[Tim H]

Not sure about high-nickel, but the front area behind timing cover used to to have numbers relating to nickel content in the old prodution blocks as I recall...

[Michael Kilduff]

Actually I'd be very suprised if GM used 'high nickel' in production blocks. I remember tearing down quite a few sbc's of 60's and 70's vintage out of crashed up cars in yards that had the 010 and 020 numbers in the castings...if that indeed correlated to high nickel content surely the cost to produce would be higher than using iron instead. Some of these blocks/engines were 307's and low performance 350 impalas and chevelles-4 door 2 barrel cars. No need to put expensive castings in those kinds of cars I would think.

[Tom Meyer]

If I remeber right chevy had a high nickle 4in block in the late 70s early 80s the number was in how to build a small block chevy book in that era I think I still have that book somewhere. My brother ordered one back in the day and never did anything with it. It was over 500$ back then. The 721 chevy II block from 1964 was also supost to be high nickle the 283 block that could be borded to 4 in. Tom

[Michael Kilduff]

Originally Posted by ss wannabee

Having an argument with a friend. I always thought that they were only available in the Chevy Performance Catalog...usually as a Bowtie block or something like that.

He says that some production-line blocks were high-nickel as well. Never heard of this...checked online...and the banter goes on and on...

Need the straight scoop..First WHAT is a high-nickel block? Isn't it really the percentage of (tin) in the cast-iron slurry at the foundry? Could the Bowtie or similar performance-catalog blocks have percentages of 10% or more?

Did regular cast blocks have a small percentage...(maybe 1, 2, or 3 %) anyway...and did GM adjust this... as needed...for production-line performance or Truck applications?

You machinists out there probably know...I hear these "hard" blocks are tough on cutting bits and stones....

I think if the percentage of nickel or tin was 10% or more the metal would no longer be 'cast iron'...it would be a different alloy.

[Dennis P Chapman]

I was told that the 010/020 blocks were better blocks and higher nickel in them. I have one in the garage for years it's also 4 bolt mains.

[Eddies66]

Edit: David Vizard says this in his book "Budget Building Max Performance Chevy Small Blocks:"

"The best blocks to get are the blocks that have a number 010 and 020 under the timing chain cover. These have 1% tin, and 2% nickel. The tin is used to help the metal flow better into the casting mold.

These blocks are the least prone to cracking. Also, because they pour more easily, they have the least problems with hot spots caused by porous metal. If you find a block that only has one number that's either a 010 or a 020, this means it has no additionally added tin, but does have one or two percent nickel."

[Greg Reimer 7376]

I always heard, knew, was told that the 010 casting 4 inch bore 350 block was the starting place. When tearing it down and the timing cover and the cam gear were removed, the numbers 010 were visible to the right of the cam bearing boss, about a half inch high. If the number under that was 020, that was the block. They came in 4 and 2 bolt mains, in fact, the last one I had came out of my 71 El Camino. In fact, it was the original engine from that car, as the VIN matched the car. Now, having found a block, that doesn't mean you can just go hog wild. It has to be sonic tested. Core shift was all over the place back then, just because it had the optimal material doesn't mean the casting cores were in the right place. My block was filled, then line honed, bored, then power honed, dummy assembled, the deck height was determined, then disassembled and decked. I will say that it was 13 years from the time I built it in 1998 and blew it up in 2011. Rod failure to blame. I think that by the time you buy and open up several engine cores until you find one, then mag it, sonic test it, and finally have a good casting, you could have gotten the legal replacement Dart block, machined it as necessary, and had a better motor. The Dart block won't need to be filled, it is noticibly more heavy than a factory casting, but you would be time and money ahead doing that. Actually, the best OEM block I ever found was a 660 casting-four inch bore two bolt main large journal 327 casting from a 68 Chevy.It came up with no core shift, the cam and the lifters were in the right place, the mains were correctly centered, and it's in my wagon right now. It's the best 327 I've turned out yet. You don't always have to have the 010-020 casting to have a good motor.