new 289
5th Gear Member
Joined: Feb 2005
Posts: 2,707
From: San Francisco
RE: new 289
shorter piston rods increase displacement. i think stroker kits come with a differnt crank shaft that pushes the piston farther up the cylander, but since it has a shorter rod, it gets pulled out more on each stroke thus increasing the displacement.....
i could be wrong...but someone can correct or confirm...
i could be wrong...but someone can correct or confirm...
5th Gear Member
Joined: Jan 2006
Posts: 3,946
From: Colorado
RE: new 289
I never quite understood why there is always so much confusion over short block, long block, small block, big block. Hey it sounds like Dr. Sues! Short block ain't got no heads, long block does. It ain't got diddly dink to do with the size of the block or the displacement.
5th Gear Member
Joined: Feb 2005
Posts: 2,707
From: San Francisco
RE: new 289
yeah.
short block = less stuff already on it.....usually crank, pistons, timing chain.....
long stuff = pretty much everything except like the manifold, carb, airfilter and distributor and stuff....
big block = big displacement engine
small block = small displacement engine
this is all generally speaking
short block = less stuff already on it.....usually crank, pistons, timing chain.....
long stuff = pretty much everything except like the manifold, carb, airfilter and distributor and stuff....
big block = big displacement engine
small block = small displacement engine
this is all generally speaking
5th Gear Member
Joined: Mar 2005
Posts: 3,566
From: Marquette Mi
RE: new 289
The only things that change displacement is bore and stroke. Adding a longer rod will just move the piston in a different place in the cylinder. To keep the same compression ratio, the pin boss (where the rod attaches to the piston) must be moved closer to the crown, or top of piston.
Short strokes are good for high rpm. It has to do with how fast the piston is moving, and how fast it has to change directions, and how far it has to move. Moving something one inch is easier tham moving it 4 inches, there is less stress on the parts and less friction. The draw back is torque is reduced so more rpm must be used to make up for the short stroke.
Some engines are designed with a very short stroke so they can operate at a very high rpm. Usually that is the case because they are class limited in displacement. So how do you get 1400 hp out of 2 liters? Make it a V12 with a very short stroke, short deck, and oversquare bore. That means the bore is bigger than the stroke. Then add a couple turbos and you have a Formula 1 engine. They have alot of gears because the rpm range is so high and so narrow they need to make up for it with gears. They dont even start making power untill around 8000 rpm.
Long strokes make more torque and under 5250 rpm, torque is what matters. Especially for a street engine. They have greater leverage from a longer lever, like the difference between a 1/4" drive ratchet and a 1/2" drive ratchet. The 1/2" drive is longer so you can apply more torque. Take the 400M, it has a 4" bore and a 4" stroke. The 351M has a 4" bore and a 3.5" stroke. The 400 will make more torque at a lower rpm than the 351 everything else being the same. It has an additional .5" of leverage from the pistons, turning the crank. Up to a certain point, a longer stroke is good for a drag engine, unless limited by class rules.
Have you seen how well a 347 runs compared to a 302? The difference is a 3" stroke to a 3.5" stroke, which has more effect than the .030 or .060 increase in bore.
Short strokes are good for high rpm. It has to do with how fast the piston is moving, and how fast it has to change directions, and how far it has to move. Moving something one inch is easier tham moving it 4 inches, there is less stress on the parts and less friction. The draw back is torque is reduced so more rpm must be used to make up for the short stroke.
Some engines are designed with a very short stroke so they can operate at a very high rpm. Usually that is the case because they are class limited in displacement. So how do you get 1400 hp out of 2 liters? Make it a V12 with a very short stroke, short deck, and oversquare bore. That means the bore is bigger than the stroke. Then add a couple turbos and you have a Formula 1 engine. They have alot of gears because the rpm range is so high and so narrow they need to make up for it with gears. They dont even start making power untill around 8000 rpm.
Long strokes make more torque and under 5250 rpm, torque is what matters. Especially for a street engine. They have greater leverage from a longer lever, like the difference between a 1/4" drive ratchet and a 1/2" drive ratchet. The 1/2" drive is longer so you can apply more torque. Take the 400M, it has a 4" bore and a 4" stroke. The 351M has a 4" bore and a 3.5" stroke. The 400 will make more torque at a lower rpm than the 351 everything else being the same. It has an additional .5" of leverage from the pistons, turning the crank. Up to a certain point, a longer stroke is good for a drag engine, unless limited by class rules.
Have you seen how well a 347 runs compared to a 302? The difference is a 3" stroke to a 3.5" stroke, which has more effect than the .030 or .060 increase in bore.
5th Gear Member
Joined: Dec 2005
Posts: 2,634
From: SC
RE: new 289
Great post!! [sm=interesting.gif] [sm=groupwave.gif]
ORIGINAL: THUMPIN455
The only things that change displacement is bore and stroke. Adding a longer rod will just move the piston in a different place in the cylinder. To keep the same compression ratio, the pin boss (where the rod attaches to the piston) must be moved closer to the crown, or top of piston.
Short strokes are good for high rpm. It has to do with how fast the piston is moving, and how fast it has to change directions, and how far it has to move. Moving something one inch is easier tham moving it 4 inches, there is less stress on the parts and less friction. The draw back is torque is reduced so more rpm must be used to make up for the short stroke.
Some engines are designed with a very short stroke so they can operate at a very high rpm. Usually that is the case because they are class limited in displacement. So how do you get 1400 hp out of 2 liters? Make it a V12 with a very short stroke, short deck, and oversquare bore. That means the bore is bigger than the stroke. Then add a couple turbos and you have a Formula 1 engine. They have alot of gears because the rpm range is so high and so narrow they need to make up for it with gears. They dont even start making power untill around 8000 rpm.
Long strokes make more torque and under 5250 rpm, torque is what matters. Especially for a street engine. They have greater leverage from a longer lever, like the difference between a 1/4" drive ratchet and a 1/2" drive ratchet. The 1/2" drive is longer so you can apply more torque. Take the 400M, it has a 4" bore and a 4" stroke. The 351M has a 4" bore and a 3.5" stroke. The 400 will make more torque at a lower rpm than the 351 everything else being the same. It has an additional .5" of leverage from the pistons, turning the crank. Up to a certain point, a longer stroke is good for a drag engine, unless limited by class rules.
Have you seen how well a 347 runs compared to a 302? The difference is a 3" stroke to a 3.5" stroke, which has more effect than the .030 or .060 increase in bore.
The only things that change displacement is bore and stroke. Adding a longer rod will just move the piston in a different place in the cylinder. To keep the same compression ratio, the pin boss (where the rod attaches to the piston) must be moved closer to the crown, or top of piston.
Short strokes are good for high rpm. It has to do with how fast the piston is moving, and how fast it has to change directions, and how far it has to move. Moving something one inch is easier tham moving it 4 inches, there is less stress on the parts and less friction. The draw back is torque is reduced so more rpm must be used to make up for the short stroke.
Some engines are designed with a very short stroke so they can operate at a very high rpm. Usually that is the case because they are class limited in displacement. So how do you get 1400 hp out of 2 liters? Make it a V12 with a very short stroke, short deck, and oversquare bore. That means the bore is bigger than the stroke. Then add a couple turbos and you have a Formula 1 engine. They have alot of gears because the rpm range is so high and so narrow they need to make up for it with gears. They dont even start making power untill around 8000 rpm.
Long strokes make more torque and under 5250 rpm, torque is what matters. Especially for a street engine. They have greater leverage from a longer lever, like the difference between a 1/4" drive ratchet and a 1/2" drive ratchet. The 1/2" drive is longer so you can apply more torque. Take the 400M, it has a 4" bore and a 4" stroke. The 351M has a 4" bore and a 3.5" stroke. The 400 will make more torque at a lower rpm than the 351 everything else being the same. It has an additional .5" of leverage from the pistons, turning the crank. Up to a certain point, a longer stroke is good for a drag engine, unless limited by class rules.
Have you seen how well a 347 runs compared to a 302? The difference is a 3" stroke to a 3.5" stroke, which has more effect than the .030 or .060 increase in bore.
I just replaced the 6Volt 36 amp batteries in my golf cart today and went 18 holes. Shot an 82. Back was hurting me though. But, the dog enjoyed the ride. 
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