As per my other post about using an LSX block for a nitrous motor.
What would be a good bore x stroke to use?

I was originally going to build a stock block 408. Should I still use that cubic inch just in a LSX block.

I was also looking at a 4.0 stroke 4.125 bore motor for 428cuin motor.

I want to make sure that I have enough compression height/piston deck on the pistons and obviously with more stroke the thinner the piston gets.

I do like a 4.1 stroke 4.125 bore 438cuin, but I'm not sure I could spray a lot of nitrous on that piston.

This motor will have TF GenX255 LS3 heads, with a vic jr (for now) with a single stage fogger.
I want to be able to spray 400hp+ on this motor.

Thanks,

 

4" stroke x 4.155 - 4.185" bore.

 

Seems like if you are spraying 400+ the difference of a few extra cubes won't be nearly as important as strength.


Since every 0.10" of stroke is only worth about 10-11 cubes I would think a 3.9" stroke would be a good choice. It would give you another 0.10" of journal overlap (compared to a 4.0 stroke)...beefing up the weakest spot on the crank and allowing for additional C/H on the piston.

Just my .02

 

If I wanted to use a 4.0" stroke could I deck the block higher and get a custom piston with a thicker compression height? Do people do that?
Thanks for the feedback guys.

 

Deep 8 second and high 7 second cars have used a 4" stroke on std deck blocks including myself.

 

what kind of pistons do you run? and what were the compression height of them?
Or a different way to ask it what compression height do you want for "heavy" nitrous use?

 

8 second cars on stock bottom ends too...

Not saying a 4" is a weak set up (I have a 4" myself). Just the OP expressed concern about compression height so I offered a solution. At the level he wants to be I doubt he'd miss 10 cubic inches.

 

I typically like to use Diamond pistons.

1.2x Compression height would be great for "Heavy" nitrous use but you're not going to get that in a std. deck height and make cubic inches. That's where 9.8" deck height blocks with a 4.25" stroke come in handy.

A 4" stroke with a 9.24" std. deck height will net you a 1.115" compression height. Many have used this with very good success.

A 3.9" stroke would give you a better compression height then a 4" like was mentioned earlier by 74u and would work well also. ( don't know C/H off the top of my head)

Both the 4" and 3.9" will work fine.

 

What crank and rods am I looking at to be at this power level?

 

Call Callies.
They will steer you in the right direction.