At what power levels do you begin to have engine failures on s4 TII. Im trying to see if a rebuilt S4 block can satisfy my power goals. I've searched and all ive come up with is that the 13bre is stronger than the 13bt but i havent found any numbers.
Thanks for your help

 

Here's a thread that might show you what a 13bt can do. https://www.rx7club.com/time-slips-dyno-128/new-dynoo-490-hp-395-tq-593729/

 

400 without dowling. After that, the area around the oil filter casting starts to crack.

 

Could i solve this problem by using a S5 rear iron?

 

dowelling still won't save a motor, the reason the rear iron breaks is detonation from people running higher boost than recommended on pump fuels. apex seals generally die from pre-ignition which is either running lean or ignition is too far advanced.

if you setup and tune an engine correctly then even in stock form it should be fine for over 500wHP.