I picked one up at my local True Value hardware store.

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“Buy the ticket, take the ride.”
― Hunter S. Thompson

After resetting the intake to get a better seal, I still had problems idling in gear. Upon further review, the EGR block off was leaking and actually cracked. I made a new one out of 1/8" flat bar and surprisingly found the correct gasket at the local auto parts store. Put it all together and now it's actually driveable, if not a bit loud... Just needs a little carb tweaking. Hopefully that will be all it needs. Thanks to all who provided help on this.

Found this old thread I started so I thought I'd post a long overdue update: turns out what the engine needed was a valve lash adjustment. On top of that, I ditched the headers (too loud) and went back to a stock single exhaust. Much more fun to drive now!

Kickdown linkage has nothing to do with the engine dying.
Nothing.
Also on your torque I hope you didn't use a "ft/lb" rated torque wrench. At that low a value you need to convert that 5 ft/lb to the 60 im/lb and use an inch lb rated torque wrench. On a lot of them 5 ft/lb isn't even enough to move the scale, that's why so many rated in ft/lb don't even start their scale til 20 or more ft/lb. But yeah I believe the desire tq on them is around 10. Or 120 in/lb.

Pretty sure I used a 1/4" drive inch-pound torque wrench and pulled the nuts down to 120 inch-pounds. No issues since