Engine Displacement Questions

ElrodKTPQ_89 · Aug 11, 2014

Ok at the risk of me looking like a dummy :tongue3: I have a couple of questions. I figured this would be the best place to ask such questions in also with out getting shot down, lol.
After having my engine (5.0) bored .20 over, what does that make my engine displacement? I'm guessing not a 306, but I don't really know what to tell people when someone asks, lol. But then at the same time what is done different to build a 306, 331, or 347? I guess I don't really understand all the bore/stroke and how you calculate displacement based on that. And also how do you determine size in liters? Somebody enlighten me, I love to learn! I know I should know all this stuff just never was taught I guess :undecided:

Addermk2 · Aug 11, 2014

Just tell people its a 302, 20 over.

People are going to think you're retarded if you say its a 305 (304.62)

kb1982 · Aug 11, 2014

A stock 5.0 has a 4 inch bore, and a 3 inch stroke crank. To get more cubes, you can increase bore, stroke, or both. Since you can only bore an engine so far before the cylinder bores get to thin, and issues arise, people add more stroke to the crankshaft. A crank with a 3.250 stroke makes a 331, and 3.4 stroke crank is used in 347 stroker. This is with stock blocks. After market blocks such as the Dart blocks can be bored out considerably bigger, all the way to 4.185. So the max size with a 3.4 stroke and a 4.185 bore in a Dart block would give you a 374 (374.15) There are such things a short rod stroker and long rosd strokers but that is a different can of worms. Here is a good website to calculate displacement. http://www.wallaceracing.com/cid.php

RichV · Aug 11, 2014

D=(pi)/4 (B)[SUP]2[/SUP] x S x N

D=displacement
B=bore
S=stroke
N=number of cylinders

To convert to Litre, you multiply ci by 16.39cc/ci and end up with cc, then divide by 1000 for Litre.

A 306 is just a .030 over 302.
A 331 is a stroked 302, so is a 347. Stroked means it has a aftermarket crankshaft that increases the stroke. Bore is the same.

Standard 302, B=4" S=3"

Pi/4 x (4x4) x 3 x 8
3.14/4 x 9 x 32
=301.59ci x 16.39 = 4943cc which is a 4.9L

What?? My 5.0 is actualy a 4.9???!!!!

ElrodKTPQ_89 · Aug 11, 2014

Addermk2 said:
Just tell people its a 302, 20 over.

People are going to think you're retarded if you say its a 305 (304.62)

My thoughts exactly.

kb1982 said:
A stock 5.0 has a 4 inch bore, and a 3 inch stroke crank. To get more cubes, you can increase bore, stroke, or both. Since you can only bore an engine so far before the cylinder bores get to thin, and issues arise, people add more stroke to the crankshaft. A crank with a 3.250 stroke makes a 331, and 3.4 stroke crank is used in 347 stroker. This is with stock blocks. After market blocks such as the Dart blocks can be bored out considerably bigger, all the way to 4.185. So the max size with a 3.4 stroke and a 4.185 bore in a Dart block would give you a 374 (374.15) There are such things a short rod stroker and long rosd strokers but that is a different can of worms. Here is a good website to calculate displacement. http://www.wallaceracing.com/cid.php

Thanks that cleared up a lot for me actually. I was aware of only being able to bore a stock block so much, but I didn't know what difference a bigger crank made.

RichV said:
D=(pi)/4 (B)[SUP]2[/SUP] x S x N

D=displacement
B=bore
S=stroke
N=number of cylinders

To convert to Litre, you multiply ci by 16.39cc/ci and end up with cc, then divide by 1000 for Litre.

A 306 is just a .030 over 302.
A 331 is a stroked 302, so is a 347. Stroked means it has a aftermarket crankshaft that increases the stroke. Bore is the same.

Standard 302, B=4" S=3"

Pi/4 x (4x4) x 3 x 8
3.14/4 x 9 x 32
=301.59ci x 16.39 = 4943cc which is a 4.9L

What?? My 5.0 is actualy a 4.9???!!!!

Thanks Rich! After reading that formula now I know I've seen it before but just forgot. Thanks for all the info guys!