Just build what you have and have fun. It's really not that difficult to figure out.

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- Thread starter eschroeder1
- Start date

Just build what you have and have fun. It's really not that difficult to figure out.

A 383 has the same bore size as a 426 Hemi. Just saying. . . .

The little things again.A 383 has the same bore size as a 426 Hemi. Just saying. . . .

What a 383 does NOT share in common with the HEMI.... does it really even bear mentioning?

Go watch Nick's garage. He has notoriously conservative Dyno. He built a numbers matching hemi, right down to the points ignition. That bad boy made damn close to 500 HP, bone stock, manifolds and all!

The factory 383 would struggle to get to 400. It's just not the same league.

Correlating different engines based on bore sizes (and other such metrics like rod ratio, bore and stroke ratio etc) is misinforming people. That's the little **** that barely matters.

Ok, thanks for clarifying. It wasn't clearMy comment was a response to prior comments disparaging the 383's small bore. Of course a stock 383 makes no where near the power of a stock 426 Hemi. C,mon. . . .

Oh, that's OK. Hope I wasn't too much of a smartass.

I was being smart too. We're a callous bunch aren't we? This place isn't for the thin skinned.Oh, that's OK. Hope I wasn't too much of a smartass.

What makes it magic?

Volume of a cylinder times the number of cylinder (for the newbies)Same formula but I do it in a different order. BxBxSx785x8. I don't put the 4 at the end. Maybe that's the difference.

((Bore² x π / 4) x Stroke) x 8

(4.250² x 3.1416 / 4 ) x 3.750 x 8 = 425.59 and that rounds up to 426 inches cubed.

For an automobile engine, the bore would be the diameter, and height would be the stroke, and, of course, you need to multiply the volume of one cylinder by however many cylinders the engine has.

You can start by dividing the bore by 2 and then squaring it, or you can square the bore and divide by 4. Same number either way. You can avoid remembering pi by using one of the formulas available online that mathematically combines various of these numbers. There's more than one such formula, because there's more than one way to combine the numbers. Downside is that you have to remember the formula. For me, it's easiest to remember (pi)(r squared)(h) times however many cylinders the engine has. But whatever floats your boat.

Any way you figure it, put a 440 crank in a standard bore 383 and you end up with 426 cubes.

Your pi÷4 is where the .7854 constant that I use comes from. A handy little circle on most calculators.

B x b x s x 8 x .7854

B x b x s x 8 x .7854

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