Dear List: I was thinking about I should tell or not this information...but I got many help from this list and I think I should shire what I know...(Please do not misunderstand I thought I was not sure this information is useful to you or not) I was researching B28F and B280F because I think newer parts are better quality and it has extra 15 hp. You may think 15 hp is too little, but 15 hp is a lot for 130 hp 's NA engine modification. Also if I use newer component, I can modification from base 145 hp. What I am thinking now is polish intake and exhaust port (very dangerous if you do not know anything), shot peeing and balancing (polish and check weight and size) most engine components. I may use Aluminum cam gears and pulleys and titanium bolts and nuts. I am still researching. I am going to start this project next year.(After I got big money...) According to Haynes Volvo 740& 760 Automotive Repair Manual Differences between B28F and B280F Identification: B28F Continuous injection system B280F LH-Jetronic fuel injection Compression ratio B28F 8.8:1 B280F 9.5:1 Liner seal thickness: B28F blue mark 0,070 - 0,105 mm White mark 0,085 - 0,120 mm Red mark 0,105 -0,140 mm Yellow mark 0,130 - 0,165 mm B280F Orange mark 0,098 - 0,134 mm White mark 0,118 - 0,154 mm Blue mark 0,138 - 0.94 mm Yellow mark 0,130 - 0,165 mm Pistons Diameter B28F Grade A:90,970 - 90,980 mm B:90,980 - 90,990 mm C: 90,990 - 91,000 mm B280F Grade A:90,920 - 90,930 mm B:90,930 - 90,940 mm C: 90,940 - 90,950 mm Intake valves Head diameter B28F 44mm B280F 45.3mm Valve head angle B28F 29.5% B280F 44.5% Exhaust valves Head diameter B28F 37mm B280F 38.5mm Valve head angle B28F 44.5% B280F 44.5% Valve seat angle: B28F Compound(60-30-15) B280F 45 Camshafts Max Lift (at lobe) B28F Intake 5.44mm Exhaust 5.94mm B280F Intake 5.96mm Exhaust 5.43mm Crankshaft Connecting rod bearing journal diameter B28F Standard 52,267 - 52,286 mm Undersize 51,967 - 51,986 mm B280F Standard 59,971 - 51,990 mm Blacknight