I know a few "strokers" tongue.gif

I hear of people talking about stroking an engine or having a stroker, But never knew what it meant.

I guess i'm out of the loop on this one.

Its putting a longer stroke crank in a motor that came stock with a smaller crank, ex: putting a 400 crank in a 350 motor. Putting a 4.25 crank in a 454 which has a stock 4.00 stroke.

Even I blushed at what I just edited out :D

remember this formula


bore x bore x stroke x .7854 x number of cylinders

or

350 chevy

4.0 x 4.0 x 3.48 x .7854 x 8 = 349.8

if you put a larger stroke crank in it

4.0 x 4.0 x 3.76 x .7854 x 8 = 377.9


.7854 is a constant. Its 1/4 of Pi ( 3.174 ) since we are working with a round bore we need this for the formula.


you see just py putting a crank in with a longer stroke it make the piston travel farther in each rotation, this increases the size of the engine and has an effect on the power produced.

I follow you with power. What does it do for tourqe?

Does the longer stroke make the engine take longer to reach higher RPM's?

Also I would think you would have to be concerned with clearence at the bottom of the cylinder and the crank.

I guess you have to make sure and do your homework to know what is going to fit.


Interesting.......

Also can you "stroke" a Big Block??

The longer stroke has a very large impact on torque. A stroker motor tends to make power at a lower RPM compared with an engine of equal size ( displacement) but with a short stroke.

You can stroke just about any engine. The 350 chevy is a "factory" stroked 327 and the 327 is a factory stroked 302

As for big blocks the 454 is a "stroked" 427.

You can also "de-stroke" an engine for example a 400 SB with a 350 crank makes a 377 and they are good for high rpms. I believe the 302's were like this might have been 327 bore with a 283 stroke? Also there are after market cranks made too stroke a 454 too a 496 or you can stroke a 400 SB too a 434? Im sure there are many other combinations. As you mentioned there are clearence issues in some cases. I know on a 383 SB you have too do a little bit of grinding on the block too clear some of the rods.

Originally posted by ACLineman:
I follow you with power. What does it do for tourqe?

Does the longer stroke make the engine take longer to reach higher RPM's?

Also I would think you would have to be concerned with clearence at the bottom of the cylinder and the crank.

I guess you have to make sure and do your homework to know what is going to fit.


Interesting....... It increases torque by increasing the moment arm of the crankshaft throw. Think of it like this. Remember the simple lever? If you incease the length of the lever arm, you can lift the same load with less effort OR you can lift more load with the same effort. This is what increasing the stroke does to the torque output of an engine.

So what would you say would be better at the track....Tourqe or HP????

At the track you need to consider things like vehicle weight and gearing as well as length of the track. I would think torque would be king in an 1/8 mile track. And torque is what guys with heavy cars seem to swear by. But don't tell that to 427L88/Gene, he runs and HP-style 427 and says forget the torque generators!

But it does seem like high torque moves heavy cars better and high horses can make lighter cars fly.