I used one of them Adjustable Rubber Freeze Plugs from Vatozone, works great,(thanks for the idea team39763 ) not as nice looking as the GM plug, but it works, think its cheaper too , I Forgot the Size ,thinks its around 1 3/8 or so ,was going to try hammering in a regular freeze plug but i was worried i might crack the intake, Had the red plastic cap off of a WD-40 can siliconed on there for months before it collapsed and got sucked in.