Unfortunately, I think some are reading into my post, beyond what I'm posting. My question isn't a simple one, I know, because I've done my research. My '69 273 is running OK, however I thought to increase its ability, for now. At some point I may install another engine, but when I don't have to, then I see no reason to. I didn't realize the 273 was so disposable that there are limits to aftermarket performance parts for this engine. Mopar kept changing things in the 60's making it hard to keep up with the changes. I understand emissions were introduced as a concern back then that changed everything. I'm on hold right now with Edelbrock, just got off the phone with Weiand, no help there. I'll take it from here, I just thought someone may have run into this issue before me and that I might be able to learn from their research. Thanks for all the assistance. Glenn