Yes, I've been doing a little searching on that, straight out is an option. See the picture above.
There is a cheap one on eBay $30something that uses a SBC thermostat...but that doesn't work well with the LS waterpump and water will bypass the heater core. There is another I've found that uses the correct style thermostat, that's the one I'm looking at.
http://www.ebay.com/itm/CBM-10613-GM...983173&vxp=mtr