C301 block

I was at a pull a few weeks ago talking with a man who currently runs a V8 Nostalgia tractor (M with a V8). Prior to this, and for the last 30+ years, he has pulled many tractors including but not limited to IH"s with supercharged 301"s with superchargers. He even pulled with NTPA for a few years chasing points. I"m giving you this information because what I"m about to tell you came from this man"s mouth during a conversation we were having over 301"s.

He said the cylinder bore "thickness" is much thicker on a 301 and if I want to see for myself, he told me to pull a freeze plug out of a 301 and compare it with a 263 or 291. He said the outer wall (where the water touches) will be much closer to the outside of the block on a 301. He said you can put your finger in the freeze plug hole and tell the difference.

I find this absolutely amazing. And if I didn"t hear this from a man who has personally built many of these engines, and blown up quite a few, I would dismiss it as sheer nonsense.

My understanding has always been a 301 runs the piston right on the bore and sleeves are used to sleeve down to a 291, 282, 263, etc. So why on earth would the cyl wall be thicker on a 301 than a 291 or 263? .. or did they do it so they could be bored over a few times ?

Anyone ? Is he correct ? Thanks

But what I'm asking is do you have first hand personal knowledge of the topic at hand. ie: you've measured the wall thickness, or you have gone through some other measuring process to verify wall thickness (sonic testing for example) and have done the same on a 263 for comparison ?

And here's the reason I ask. If I were the engineer on the original casting, I would make all castings the same (say 3/8 wall thickness) and during final machining, machine the bore for a 301 and if it's a 291 or 263, either find a sleeve with a OD that matches the 301 bore or simply set the final bore to whatever the closest sleeve OD is available.

Given that, you could do the sleeve/piston replacement as often as needed, and bore the 301 once (.030) or twice (.060) before needing sleeves at some future rebuild.

Now it is possible they needed to "reduce" the casting wall thickness on a 263 for cooling reasons, ie: too much total thickness between the casting and the sleeve for the heat to transfer... and that could answer why (if it's true) a 263 has a smaller outside diameter cylinder casting.

Once again, I'm looking for "personal knowledge" on the subject and if your first reply was one of personal knowledge, just state the fact and I will thank you for your time and go look for a 301 block to bore out instead of wasting my time with a 263.

Mark
Thanks

Gordo