how to convert

if a have 300rwhp how do i convert it to engine hp if a have a manual box?? or maybe 1 of you inteligent people could do it for me![img]/phpBB/images/smiles/icon_smile.gif[/img]

Arithmetic central...
A popular guess is that the drive train absorbs 15% of the power, so if you divide the net 300rwhp by 85% you will get the gross of 353. You can't just add 15%, you need to add 17.65% to get the gross. The test is 353fwhp x 85% = 300. So either divide by 85% or mark it up 17.65%.

I read that RWHP is calculated by subtracting 18% for a manual and 25% for an automatic. These are approximations. For an exact measurement, put it on a dyno.