all 4/5e heads are the same casting wise. i have had all different variants of them (4efe, 4efte, 5efhe and 5efe) they are all the same. the 4efe springs are pretty weak and wont let you rev over about 7 as they start floating the valves. 5efe is pretty much the same. the 4efte head has slightly stiffer springs, they rev to 8 without trouble. the 5efhe has stiffer springs (like the fte) and also the exhaust cam on the ACIS/Cynos variant has a slightly higher lift. ive got a set of FTE valve springs laying about somewhere, you can have them if you like/i can find them. they are the only difference between the fe and the fte heads. hope that helps.