Great post – Welcome to CHR!

As you’ve already ascertained, Tech is a fountain of knowledge – listen and soak up his wisdom. I’ve been roddin’ almost as long and he continues to teach me!

If you have not bought the 700R4, I’d suggest a 200R4. For the most part it is a bolt-in replacement of your TH350.
1. You re-use your current the driveshaft with no modifications whatsoever required. A 700R4 requires driveshaft to be shortened.
2. You can use your existing cross member – needs to be moved back 6 inches and new holes drilled - use Grade 5 or better bolts.
3. Same transmission cooler lines as the TH350.
4. Same shift linkage (can even get a new little window showing all 4 gears).
5. Same throttle cable and cable bracket at the carb.

There’s also the ratios – your TH350 is 2.52 in first. The 200R4 is 2.74 and the 700R4 drops to 3.06. Might not sound like a big deal but is huge on takeoff. Also at the other end, the OD on the 200R4 is .67 where the 700R4 is .70 – not huge but at speeds below 50-60MPH (depending on rearend ratio and tire size) there will be a lot of 3rd to 4th to 3rd going on.

I’d also second the Chevrolet Performance 12558060 (L31) heads. They’re readily available from several sources and a pair will be well below a grand – even with gaskets and some polished aluminum valve covers. Bear in mind that a new intake is required but Summit, JEGS and others have a kit that includes everything you need for this swap.

Ditto on the cam selection as well. I’ve installed a ton of flat tappet cams with very little trouble but the writing has been on the wall for some time as to their future – rollers are certainly the way to go.

Most important in this whole post is the father son aspect of the project. I bought my son a ’71 C10 when he graduated from high school. 350/350 real stock. We swapped the original intake for a dual plane aluminum, Edelbrock 1406 (yes – it was tamer that the stock Quadrajet), big free breathing air cleaner, Hooker ceramic headers, and HEI ignition. Went with 285/60 15 tires and GM SS rims, new Cheyenne interior and a tilt column. That was 13 years ago and it’s running like a champ – very fun to drive and he still loves it. I can not tell you how fantastic it is to see him and his beautiful wife snuggled together on that big bench seat to go for a drive. I have a new performance Q-Jet to re-install at some date, but the truck is just a great ride as is.

Have fun with this – memories will be made.

Glenn