Builders: Square engine, Over Square, or Under Square for you?
- Thread starter 318willrun
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You're dang sure right. I guess I had Cleveland on the brain. Thanks.
Some Ford guy jeez...lol
I know, right? LOL
I work on all brands at work, just matching so unless it's a Mopar I couldn't tell you what the deck height is on any of them lol
Newbomb Turk
Well-Known Member
Good thing you can sing and play geetar. Because your memory is about as junky as mine is.
I knew all this stuff when I was a mechanic and machinist and stayed with it, but I've been out of touch professionally for a long time now. We all know how out of touch mentally I am.
Right!
As am I lol
I consider myself in good company then!
Use it or loose it what I was told.
I write stuff down now. If I don’t make a too do list, I do nothing.
My library still yet grows.
That's very true.
Topless69
Well-Known Member
For N/A stuff, big bore, short stroke. Most Aussie Pro Stock engines are 4.2" + bore, with around a 3.6" stroke. RPM is always king when making HP.
Deck height will usually be as low as the package or available block allows.
Rod ratio depends on the builder's preference, ideally you want to keep all of the piston skirt in the bore, as it can tear them up if the skirts protude too low at BDC.
Rod ratios of around 1.6 - 1.68 are pretty common in various PS and Comp Eliminator engines, although Mountain Motor Pro Stock it's around 1.3:1
Many things have changed for these engines to evolve, advances in manufacturing processes and materials, data collection, design simulation etc.
Using a 0.5 mm (0.0196") top and second steel piston ring would have been crazy talk 20 years ago.
Deck height will usually be as low as the package or available block allows.
Rod ratio depends on the builder's preference, ideally you want to keep all of the piston skirt in the bore, as it can tear them up if the skirts protude too low at BDC.
Rod ratios of around 1.6 - 1.68 are pretty common in various PS and Comp Eliminator engines, although Mountain Motor Pro Stock it's around 1.3:1
Many things have changed for these engines to evolve, advances in manufacturing processes and materials, data collection, design simulation etc.
Using a 0.5 mm (0.0196") top and second steel piston ring would have been crazy talk 20 years ago.
Dale Davies
Well-Known Member
4" bore and 4" stroke makes a good balance of torque and power. Mopar, Chev and Ford all have blocks to fit the bill.
And which Mopar and Chevy engine is that?
360 with a 4" crank (stroker) is a square engine. 4 " x 4"
Not from Chrysler it ain't.
Ford was the only square 400 from the factory.
I think he said they all have blocks to fill the bill..... he didn't say factory stroke crank and block
He wasn't very specific, was he? lolI think he said they all have blocks to fill the bill..... he didn't say factory stroke crank and block
Looking through old magazines....SS & DI Dec 79. Article on long & short rods. Apparently at that time there was a junior fuel Chevy class. Ran fastest with a 1.9 r/s ratio, but et'd best with a 1.75 ratio. Junior fuellers were limited to 310 ci & had NO transmissions. With a 1.9 ratio, they would run 198-199 mph. With a 1.5 ratio, these turned about 185mph but regularly et'd 1 or 2 tenths quicker.
A hell of a lot has changed in 45 years, I doubt that much of that would be particularly relevant now
IDK about that. This comes down to physics, I believe.
Newbomb Turk
Well-Known Member
The physics are the same but the cylinder heads aren’t.
High (how long is a rope???) rod to stroke ratios helped with undersized ports.
You can just about get any cross section you need if you spend the money.
Then it becomes less critical but it still matters because it affects cam timing.
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