I did a how to on the DBW throttle bodies a while back... A small dremmel will take HOURS, but a 1/4" chuck die grinder will power through it in less than 1 hour...

https://www.performancetrucks.net/fo...light=throttle

Done several for members here and on silveradoss.com with very few complaints (one had to have a throttle plate adjustment). All of them that I've installed locally have worked fine with no need for tuning or idle adjustment. If you have any questions, let me know.

BTW, redLS1rado, you need to fill with epoxy and redrill those passages there to smooth out the airflow around them.

Also, a typical LS1 with this mod is shown to gain between 5-10 throughout the entire RPM range. I've seen 3-8 RWHP gained on ones I've done locally.

 

I used my dremel with the sanding drum to grind it down. Then I used some 2000 grit sand paper and sanded everything. Then polished it with my dremel and polishing compound.

Yeah I was going to do that but I didnt really feel like it.