TOPIC: TBI 2"-Bored Units Require Medium Bit Size

Hello out there, this tip is from me to everyone out there to say learn from what I did.

This is ONLY for TBI Units that have been Bored out to 2" for 645 CFM airflow, 300+ HP.

The modified Throttle bodies as shown in the pics below will illustrate what I mean. The bored TBI unit only has 3.8mm thickness at the bottom of the groove, where the original TBI has 5.92mm. Can you guess what happened? Lets just say that I carved a slot big enough in the passenger side that I went through the bolt hole, the entire bottom groove and the iac re-route. I'll be saving for a new TBI but that will take a few months.

I also had the throttle plate pushed out 2.5 turns to allow for 15% throttle before the groove took hold.



Stay groovy, and even with the not so great groove she still wants to burn the tires off the axles.

Enjoy the pics, and ask questions if something isn't clear.

Ken



New Bored Throttle Body, notice the thin section at the bottom?



Measurement of new throttle body.



Measurement of Old Throttle Body. (Large bit had no issues)



First cut through bolt hole area, patching this while making it large enough for the bolt was plenty of fun.



Picture looking down into passenger side groove, had to fill the entire IAC to regroove this.



Other side was much thicker, only broke through a little on driver side.

Pretty epic looking work there, Ken! Yes that thin bore wall section is a challenge all right. Thanks for the pics detail, I bet you have the Only one of it's kind on earth!

Tracy G

I have seriously thought about filling in that groove and using the medium size bit; but Ron's voice keeps echoing in my head when he was talking to the gadgetman in Nebraska about always using the largest bit possible even if the shape is a little off.

I'll see how this groove works and maybe try the other but not for a while; i'm having too much fun driving with the groove again. Ha!


Hopefully i'm not the only non-certified guy out here that kept watching tons of Rons videos before i'd even attempt at working on someones throttle-body. Trying to match how Ron held the tools in his hand really helps me to keep the groove consistent throughout the cut.