I have a new 357 lt1 with a cc503 cam and im using a 58mm Summit TB. Iam having idle problems during cold start and when braking at stop lights. Was i supposed to drill the IAC on the TB? what size should i drill the hole?

 

Do you have a scanner? What is the IAC doing?

No physical mods are to be done until you know what is going on. There are most likely several things going on.

This is best asked in the computer section as your problems are related to programming, not the engine.

BTW, these are common problems with simple solutions...for the most part.

 

I had to drill my Summit TB. I used the closest bit that matched the hole in the stocker. Dont remember the actual size. I had to tweak the blades open a bit too. IAC counts are high 40's. Idles perfect now.

 

I dont have a scanner, i did drill a whole the same size as the stocker, its idleling close to perfect now. thanks!

 

A modded motor needs more air than stock so if you do it RIGHT you will probably endup bigger than stock and you should have the TB blades closed.