What are my options?

[turboclam]

I've got a virgin stage II off-center. I'm just weighing the different stroke combos. More of a street car than anything but I want to keep the bore size down. It will be a GN1 aluminum headed car with a stock ported intake. What would the cubic inch be with a stock stroke vs 3.590 vs 3.625. Advantages or disadvantages on all please... like readibly available rods and such. I know there's a formula factoring ci somewhere but I can't find it. The compression will be in the 8.5 to 1 area. I've just heard on the Mustang 302 blocks that a 331 stroker will out live a 347 on the street as far as wear and tear. Thanks for the time!

 

[Nasty Wendy]

pi*R² X Stroke X 6 = displacement

R is the radius of the piston.

 

[gnxtc2]

With a 4.00 bore

Stock 3.400 = 256
3.59 = 270
3.625 = 272

If you want to play with bore size, just plug in the correct numbers:

Jack Merkel Performance Engines > Engines > Performance Calculator

Billy T.
gnxtc2@aol.com

 

[turboclam]

So what do you think would hold up longer? Does a bigger stroke put more wear and tear on a motor? Thanks

 

[turbodave231]

Both the 3.590 and 3.625 stroke cranks have been used extensively in these engines. I'd make my choice based on cost and availability of a good crank and rods.

Personally I did the 3.590 stroke and 4.00 bore in my engine. But either combo is a good choice.

Dan at DLS has sold some nice forged 3.625 cranks with wide rod journals for under $900. He also had billet cranks, but I'm not sure on the price. He was supposed to have rods, but I haven't heard anything about the rods lately.

 

[Nasty Wendy]

Dan also sells a 3.75" stroker crank.

 

[Big Turbo Scott]

pi*R² X Stroke X 6 = displacement

R is the radius of the piston.

CID= NOC X .7854 X (bore)2 x stroke. NOC= number of cylinders

 

[Big Turbo Scott]

I've got a virgin stage II off-center. I'm just weighing the different stroke combos. More of a street car than anything but I want to keep the bore size down. It will be a GN1 aluminum headed car with a stock ported intake. What would the cubic inch be with a stock stroke vs 3.590 vs 3.625. Advantages or disadvantages on all please... like readibly available rods and such. I know there's a formula factoring ci somewhere but I can't find it. The compression will be in the 8.5 to 1 area. I've just heard on the Mustang 302 blocks that a 331 stroker will out live a 347 on the street as far as wear and tear. Thanks for the time!

Mike, A few things to consider. Increase in bore will add to the frictional loss just as adding stroke since the piston will travel further per revolution. The draw back to adding stroke is the rod angle at 90^. The rod will load the piston as it is being pushed back to TDC wearing the cylinder wall. But, you take advantage of the longer stroke because at 90^ the rod is futher away from centerline of the crank. This is like using a 2 foot prybar vs a 5 foot prybar to move something. The increased leverage puts more torque on the crank.

A larger bore will help unshroud the valves but will leave less material for future rebuilds. For a street car, Id probably find a middle ground for both the bore and stroke. I cant wait to see how that turbo of yours responds to inches!!

This is just food for thought. Ill call ya later and we can go a little deeper.