[seattle gmc]

The heat riser is suposed to be on the passenger side. The dorman ramshorns do suck. I had a cracked manifold and bought a dorman replacement and it didn't fit well. The machining was so poor i couldn't get the center manifold bolts torqued down until i opened them up with my dremel. The bolt head was hiting the side of the manifold where they didnt machine enough metal away. And yes i had to plug the smog tube holes. Surprisingly i got another manifold from LMC and it fit well and didnt have any of the problems the doorman one did. I have no idea who manufactured it.

I guess you need to keep an eye the parts board or ebay for a straight dump ramshorn.