Just call me "Lex"
- City of Halos
This is what i found from personal experience. I have 2JZGTE stock Valve Springs in my 1UZFE heads. The stock Supra valve springs are rated at 60 lbs seat pressure for the 2JZ head. However, my engine builder tested the supra springs in 1uzfe heads were 80 lbs. There are few company selling very expensive aftermarket valve springs that are rated at 85 lbs. The reason why the stock supra springs have higher seat pressure in 1UZFE heads is because the 1uzfe valve stems are about 1/4" shorter and therefore the stock supra springs will have greater seat pressure. Interesting find nevertheless.