Just found this from Walker (printed in 2012) and says on page 3, that 575sci s/n 0L306696-0M950526 use Walker p/n 215-1026,but still unable to find the A03
http://www.walkerproducts.com/wp-con...-actuators.pdf

Thanks for all your help, I will make some calls tomorrow. Just wanted to place my order asap but wanted to make sure I knew what I was doing. I do appreciate your help.

I'd call Eddie Young - he will likely advise you of Merc vs aftermarket usage/application possibilities.

I have one in my hand for the engines that use an IAC for each throttle body.

GM# 17113099
AC Delco# 217-429

I have no use for this one anymore, no longer have 575's. PM me your address and I will send it to you if you want

I always carried a spare. Funny how these would last 200K miles in a car, but won't last 100hrs in a boat

What are the symptoms of a bad IAC? My motor loads up at idle and also keeps revving when the throttle is closed for a few seconds after high rpm operation.

High idle or won't idle. Sounds like you may need an IAC and injectors. The injectors are prone to leaking and making it load up at idle