Avernus

Ok I've been doing some reading and I'm starting to understand everything I think. I'd like to have all the information in 1 spot right next to each other.

To start:
305 and a 350 are the same block with different strokes?

Now more advanced:

305 bored(0.030) => 327

350 bored(0.030) => 355

350 Bored (0.030) and stroked (5.7"rods and high wrist pin pistons) => 383
Right?
So hypothetically
One could build a 350 to a 355 by boring 0.030 over getting pistons to match.

Then once one got more money one could stroke it with either a 400 crank or 5.7" rods w/ high wrist pin pistons and have a 383? Would one need different pistons or rods if one used a 400 crank?

Thanks for the time guys.

RexKarr

305 and 350 are completely different bore and stroke.

305 = 3.736" x 3.48"

350 = 4.000" x 3.48"

A bored 305 is not a 327. A 327 is a very different from a 305, and has more in common with a 350.

Hope that helps

Sonix

iTrader: (1)

A 327 is a 350 with a shorter throw crank as well. Just like a 377 is a 350 with a longer throw crank (or a 383 if it's bored .030" over).

Street Lethal

iTrader: (16)

Avernus, take a good look at that again. You have a .030 over 350 gaining five cubic inches, and a .030 over 305 gaining 22 cubic inches. Umm, what's wrong with this picture....?

carscomefirst

350,302,327=4"bore
283,307=3.875"bore
400=4.125"bore
267=3.5"bore
265=3.75"bore
305=3.736"bore
262=3.67"bore

267,305,350=3.48"stroke
265,302,283=3.00"stroke
307,327=3.25"stroke
262=3.10"stroke
400=3.75"stroke

Batass

377 is also a destroked 400.

Avernus

Thanks a lot guys that cleared some stuff up.

350's and 305 have the same stroke but a diffrent bore.

350's=4" bore
While a
305 =3.736" bore

However I don't under stand the engine numbers.

rexcarr said: 305 = 3.736" x 3.48"

I mean i'm not a mathematician but 3.736" x 3.48" does not sum up to 305.
prepare yourself this is completely hypothetical:
How would you determine what an engine size would it be if i said that i had a 4" bore and 4" stroke.
^ that would be a sweet engine though right hahah

Thanks a lot!

-Av

thewolf

iTrader: (5)

Area of a circle = pi * radius * radius

Volume of a cylinder = cross-sectional area * length

Remember, you have 8 cylinders. I'll leave the actual calculation as an exercise for the class.

For what it's worth, big blocks have gigantic bores. Each one seems about the size of a two-liter bottle. They can reach 4.5".

AlkyIROC

Play with this engine calculator to see what bore and stroke produces. My engine has a 4.500" bore and 4.250" stroke. I can safely bore the block to 5.600"

http://www.csgnetwork.com/cubicinchdispcalc.html

82Five-O

Wrong. a 327 is completely a different journal size than a 350, its the same as a 283 tho.

All you guys are confusing large and small journal motors. You cant turn a 305 into a 327.
The only difference in a 305 and 350 is the bore.

AlkyIROC

Actually, you can put a 400 crank into a 305, bore it out .030" and make a 334 but you'll never get a lot more displacement from just boring a 305 block. A 334 is inferior to a 327 because of the 305's smaller bore size.

Bore makes HP. Stroke makes torque.

A 305 can't compare to a Ford 302 however a Chev 302 is equal or better than the Ford 302. It's all about bore and stroke.

There are physical limits to all engine sizes. There are aftermarket BBC engines with a 5" bore. That's a huge area to get a flame front across the piston. Going huge creates a lot of other problems. Using a small bore such as a 305 can be more fuel efficient because the flame front has a smaller surface area to go across but the smaller bore also produces less HP.

A Jag V12 engine uses 12 cylinders and only has roughly 350 CID. Those are very small bores but has 4 more to produce power than a V8

Batass

4.250x5.600! ! What are you waiting for?! I heard something about a square bore, and the optimal bore/stroke ratio is 1:1, is that true?

Avernus

Wow thanks!! thats really awesome to mess with and now it's like I can even test myself. now i understand a lot more now.

I could bore out the 350 0.030 over and have a 355 for a while then stroke it from 3.48 to 3.75 and have a 383. I understand how the numbers matter but now it's a technicality that i don't understand. why 350? why 355? why 383. I don't get how 4.030 x 3.48 =383 CID. Without a engine calculator how would one calculate the CID of an engine by the bore and stroke? is there more needed? i found an x value of 25.321... when i divide 382.667 by 3.75 x 4.030 or (15.1125)

P.S. I really appreciate the patience that you all are having with me. =)

thewolf

iTrader: (5)

305, 350, or 383 refers to the displacement of the motor in question, in cubic inches; i.e., the volume of cylinder space traversed by the piston from top dead center (TDC) to bottom dead center (BDC). Knowing the bore and stroke, this is easy to calculate.

My 383 has a bore of 4.030" and a stroke of 3.750". Using the formula I gave above:

Cross sectional area of a piston (as seen from above) = pi * radius * radius
= 3.1416 * (4.030/2) * (4.030/2) = 12.7556 square inches

The volume of one cylinder is then = 12.7556 * 3.750 = 47.8334 cubic inches

Hopefully, my motor has 8 cylinders, so the total engine displacement = 47.8334 * 8 = 382.6672 cubic inches

Hence, we call that a 383. Other motors will have similar calculations, just with a different bore and stroke.

Class is dismissed!

AlkyIROC

Throw a wrench into the calculations.

Although we prefer to think in cubic inches, all engines are now measured in liters. That 350 CID is 5.7L. A 454 is 7.4L. It's still a volume measurement but just a different value. The new LS series of engines have a different bore and stroke configuration. That's why it's possible for them to make a 427 CID from a small block platform.

The 4.3L V6 is really a 350 with 2 cylinders cut off. People know it more as a 4.3L than a 262 CID.

My 540 would be considered an 8.8L or a 8.9L depending on how you round the number.

Avernus

You rock.
Thanks

camaronewbie

EXCEPT - there was also a large journal 327 block, which again is identical to a 350 block. You can install a 350 crank, pistons and rods, and have a 350 for all intensive purposes.

82Five-O

how often do you see those?

AlkyIROC

The blocks are still the same. 302, 327 and 350 all have used the 010 casting, 4" bore block. The small journal doesn't refer to the mains. It refers to the throws for the con rods. All the SBC blocks use the same main sizes except the 400 block which uses larger mains. To put a 400 crank into a 305 or 350 block, the mains need to be turned down. To put a 350 crank into a 400 block to make a 377, bearing spacers are required to take up the difference in size.

The 302 uses the same stroke as the older 283 but uses a large journal crank. Putting a 283 crank into a 010 casting block to make a 302 doesn't make a real 302 because it would require the small journal rods. Finding a factory 3" stroke crank with large journals that's forged and not cast to make a proper 302 is difficult.

avro206

Different stroke too eh? Even you figure quoted proved that wrong.

funniest statement on here! I am laughing with you.... relax.