[jerry moss]

you should not have two heat risers, only one is normal. i work in a muffler shop and we also sell a block that replaces the heatriser. a lot of people make a mistake when they work on the exhaust manifolds and use gaskets between the manifold and the head, a guarnteed leak sooner or later. have the manifolds surfaced, clean the heads real good and bolt them up metal to metal, torque the bolts correctly for proper expansion and contraction and you'll not have anymore problems. if the studs at the flange end are iffy, nows the time to replace them too. if you have old style manifolds with the choke heat tube inside, those can burn through and create a leak also, if thats the case, you can have the choke tube holes welded closed before resurfacing. hope this helps.