Cabin fever discussion.
Let's say you have engine combo X.
You destroke, maintain CR, same cam/rpm/heads/valves/boost/fuel. You adjust the tune . . . .
What's your opinion or experience on the performance results?
Cabin fever discussion.
Let's say you have engine combo X........................
The 400s were big blocks and had better heads. The early 400 with the shorter stroke was the best performance wise. The 403 suffered from crap small block heads, and they were crappy small block heads at that, low compression, and if it wanted to rev, it couldnt, because it had the worst bottom end. But lets be honest, these are Olds motors, none of them are really good performers.I can give you my experience with Oldsmobile V8's in particular the 400 cu.in. motors. Oldsmobile made 3 different 400 cu. in. motors in the day. They made a 4.00 bore X 4.00 stroke 400 cu.in., A 3.87 bore X 4.25 stroke 400 cu.in, and a 4.351 bore X 3.385 stroke 403 cu. in. motor. Overall performance meaning best low end torque and high rpm horsepower the 4.00 X 4.00 combination worked the best. You can't use the same cam profiles for the different combinations because of the different piston speeds associated with each engine. The big bore short stroke engine (403) was the worst performer but the most efficient (gas mileage) due to it's low piston speed. It had poor low end torque but would rev higher. The small bore big stroke 400 cu. in. motor ( 3.87 bore X 4.25 stroke) made good low end torque but was more rpm limited. The 4.00 bore X 4.00 stroke 400 cu. in. motor was the best compromise. It made good low end torque and still made good high rpm horsepower. Bottom line is it all depends on how the engine is going to be used. Application always determines what the best combination is.
The OP's post was about bore stroke combinations not who's engine is better. And by the way the 403 we built had big block heads (yes they do fit with a little work) with a custom made intake.The 400s were big blocks and had better heads. The early 400 with the shorter stroke was the best performance wise. The 403 suffered from crap small block heads, and they were crappy small block heads at that, low compression, and if it wanted to rev, it couldnt, because it had the worst bottom end. But lets be honest, these are Olds motors, none of them are really good performers.
Since the displacement will be smaller,it will produce less power at all rpm. On a street car,it will lose power where you want it the most,down low in the rpm. To make the same power,you will need to run more boost then rev it higher. You don't destroke to make more power,you do it because you're forced to by running in a class that limits displacement. You want to have the biggest bore possible to unshroud the valves so you give up some stroke. The fact that the destroked engine can rev high is nothing to brag about. It had better rev higher. It needs to because it is smaller.Cabin fever discussion.
Let's say you have engine combo X.
You destroke, maintain CR, same cam/rpm/heads/valves/boost/fuel. You adjust the tune . . . .
What's your opinion or experience on the performance results?
Cabin fever discussion.
Let's say you have engine combo X.
You destroke, maintain CR, same cam/rpm/heads/valves/boost/fuel. You adjust the tune . . . .
What's your opinion or experience on the performance results?
Was hoping this thread went a little further in detail with build recipes of "destroked" motors that are making big power. IE actual bore and stroke, cam, heads, rpm.
A friend of mine who has built a ton of Buick race engine (big cubic in strokers) made a statement that has stuck with me. Regarding RPM it was his opinion that higher RPM was "less" destructive than loading an engine "diesel" style. Lots of way to interpret that simple statement.