I am planning a 750-800 RWHP build. Reading threads with blackbirdws6 and Karl Ellwein, Karl mentions that he believes LT1 cylinders go out of round near the 700 hp mark. Why is this different than LS engines? I realize the iron LS blocks are stronger, but are the actual cylinder bores thicker in an iron LS?

 

I wouldn't be surprised if they do, but no one catches it or cares.

You will be fine, people have been doing it for years now. If it truly bothers you, fill the block, run a big *** oil cooler and pray you don't torch a head.

 

Not interested in block filling lol. I want my cake and eat it too, I drive it too much to worry about cooling issues.

So, what are the effects of the cylinders losing their "trueness"? I assume compression loss and/or oil consumption?

 

Mine is couple thou out and so far, no issue.

If I had to take a off the wall guess, I would say blower cars suffer more from this cause they can't control when the torque comes in. Low rpm and high torque means some very high cylinder pressures etc.

Either way a FI build will have loose rings and a potentially open PCV system so blow by is a price you pay.

 

Compression loss and blow by but it will likely live for a while with the right parts. I don't agree with SNM though. Torque spike is typically higher once the turbo spools . You are feeding the engine a greater amount of air earlier vs a centrifugal blower.

 

Half fills used to be pretty common when guys were regularly pushing the blocks back in the day, there were a good number of guys running around half filled as a weekend cruiser and at least one I can remember as a daily driver.

I believe George Baxter started having issues around 1200hp with the cylinders showing they were out of round with a half fill.

 

Ask Stefan's builder how to make them live. Tyree over at TyTech Performance. He can get them to live at well over 1000rwhp.