The type 4 case is pretty strong.The problem with the case imho is not the case itself but the hardware that holds it together,specifically the through bolts.If youīre going to build a large type 4 with a large stroker crank above 84mm and a 105mm bore than larger through bolts are the way to go.I have six 14mm through bolts that Remmele uses in my 3 liter case.A 5th or six stud system causes head leaks in my opinion.I had a 2459cc (71x105) with a 5th stud and the heads leaked.Also,if you are going to build a 3 liter or any type using a 105 bore or larger,then Engine Plus heads or Pauter heads will provide more stability and seal than an original type head.The Remmele heads are not sold to the general public by themselves. If you decide to use an original type 4 head DO NOT use a 5th or sixth stud,it just makes things worse.One option is is o seal the heads the way Porsche did on their turbomotors (aircooled) using a step machined into the head.Also in an NA application the type 4 head reaches itīs limits quickly above 2.7 liters or 220-240BHP - thatīs about as high as you can go and maintain somewhat driveability and reliability.If youīre looking for bigger numbers with an NA type 4,then different heads like Engine Plus are inevidable imho.Will a large Pauter or Autocraft have the same reliability as say a 2.7 type 4 with original heads or say a ca. 300hp 3 liter Remmele engine with the big heads? I donīt know....
As a side note: a turbocharged engine does not run hotter in traffic than an NA engine - just the opposite actually,because the heads on a high strung NA Engine usually are less efficient in cooling than a stock head with its large ports,high compression ratio,large duration/overlap cam etc..Most turbocharged engines have mild heads and while in traffic are not on boost and are basically a mild NA engine because there is no load on the motor in traffic,have less compression,milder cam,so intake heat and the associated cooling problems do not come up,unless improperly engineered
