LS1-450

iTrader: (33)

Can the inlet orifice be too small & be able to hold its' idle? I've got a drilled hole through epoxy for idle air supply (epoxy dilled area over manifild vent & idle control air where epoxy was used to continue the sloped area into the throttle body). Noticed that w/ the new block I already had to increase the diameter of the TPS inlet hole & she idles much better now. Was wondering if the hole can still be too small. Don't have a vacuum gauge to measure, but, she is sucking hard in order to get enough idle air through that hole (slight whistle). I've seen where some have also drilled a small hole in the butterfly plate to get a bit more air.

So, the question remains, if she idles well leave it alone, do we open the hole up until she doesn't sound like she's gasping for air, or should we add a small butterfly (throttle) plate hole? Should also say that it's new block & the oil fill cap will suck right back down onto the valve cover when checking for good vacuum.