Does anyone make an exact replacement o-ring thermostat housing for a 91 TPI 305. Also do you have to pull the throttle body to change out the Thermostat housing i was told this but it looks to me you don't.
Thanks
JC

 

Not too sure about an 0-ring'd thermostat housing, every gen 1 SBC I've worked on had a water neck (what some call thermostat housing) and a regular gasket you use with gasket seal on one (or both) side(s). If you need a new water neck you can buy chrome ones on E-bay. If I need one I usually goto the junkyard and find once since its not a wear item and I'm not into chrome. Just make sure the gasket mating surface isn't screwed up, can even sand, prep, and paint the neck itself if you wanna make it look good. Gasket should be available at any parts store for like $3 or somewhere around there.

Every time I've changed the thermostat I had to remove the throttlebody to get that rear water neck bolt out. Its a long bolt and its much easier to get at and remove with the throttlebody removed.