I initially planned on buying hemi style racing engine from GoPower Sports with a dyno of 11.5 HP.  But the $500 plus cost held me back.  In my eagerness to make design progress, I found I could not withstand the Harbor Freight sale price of $129, so succumbed to the lower price route.  This will also better allow me to put off the Stage 1 performance kit additions until later in the project. I think making these changes will also be fun and another great educational opportunity.  I believe Dennis and Steve both have excellent videos that detail this.  If memory serves me correctly, GoPower Sports also has a good video tutorial.

A similar story goes for the torque converter.  I initially planned on buying the GoPower Sports Super30-70 Jugg-A Verter.  I then read some comments by several people who claimed that the standard TAV was equally good as the high-priced ones.  It appears the green spring change delivers the best overall performance, so I just got one off of Ebay.