Motor is 9 years old and was advised to change the lower end seals which means lifting the powerhead. With all the bolts removed no end of force would separate the powerhead from the engine. Even with a gantry attached to the flywheel and the boat (1.4tonnes) lifted off the blocks it showed no attempt to split. Tried unscrewing the studs and that did not work either. The engineer said that the 4 long bolts at the front were typically corroded in and only extreme heat or sawing through the exhaust plate would do it. Has anyone any less destructive ideas. Needless to say I decided to just bolt the whole ting back up as there is no evidence of a problem yet.<br />Thanks