jeepthing07
06-16-2008, 10:28 AM
I am thinking about having my engine bored out .40 over. I don't know what combos make a moter a 416, 426 or a 440 i thought just boreing it out made it a 416. i don't want to stroke mine the crank and all the parts are to expensive. i just want to throw a weisco piston in mine and be done with it. i want to boost the compression up a bit but still run it off pump gas what would be a good compression to run for that?
I found this on another site is this true?
"The difference between the XR400 and the 400ex engine:
400ex: 85mm piston and 70mm of stroke. Comes stock with 9.1:1 compression ratio. Electric start only. The camshaft is a big difference. Lift and Duration .316 .302 .234 .238
XR400: 85mm piston and 70mm stroke. Comes stock with 9.3:1 compression ratio due to a thinner headgasket. The camshaft is also different. Lift and Duration- .326 .321 .240 .244
Just a fact about buying a piston for your 400ex from Wiseco. Whenever wiseco offers a piston for the 400ex engine they base their compression ratios off the XR engine. Example- If they say its an 11:1 piston its really going to be a 10.8:1 compression. To fix that problem you can put on a XR headgasket and that will bring it back up to the true compression ratio due to the 400ex having a thicker headgasket."
and how much does a shop normaly charge to over bore a cylinder? i have herd it was $20 a hole on car cylinders.
I found this on another site is this true?
"The difference between the XR400 and the 400ex engine:
400ex: 85mm piston and 70mm of stroke. Comes stock with 9.1:1 compression ratio. Electric start only. The camshaft is a big difference. Lift and Duration .316 .302 .234 .238
XR400: 85mm piston and 70mm stroke. Comes stock with 9.3:1 compression ratio due to a thinner headgasket. The camshaft is also different. Lift and Duration- .326 .321 .240 .244
Just a fact about buying a piston for your 400ex from Wiseco. Whenever wiseco offers a piston for the 400ex engine they base their compression ratios off the XR engine. Example- If they say its an 11:1 piston its really going to be a 10.8:1 compression. To fix that problem you can put on a XR headgasket and that will bring it back up to the true compression ratio due to the 400ex having a thicker headgasket."
and how much does a shop normaly charge to over bore a cylinder? i have herd it was $20 a hole on car cylinders.