Could i have a valve seal problem? I looked at old heads , plugs in same clyinder locations are clean. Engine idles a little rougher, and didn't seem to make as much power as predicted. 86gt bottem end, e7's. cobra I/T, 1 5/8 headers, pullies > made 219rwhp/278rwtrq. .Old combo> with e6's . 201rwhp/280rwtrq