Is it ok to use LT1 heads on a standard small block? I was told that it will fry the engine from differences in coolant flow unless you use an LT1 block. any insight would be greatly appreciated

They can be made to work but they are not a very good cylinder head. Even with a bunch of porting they're not even close to a good aftermarket head. A vortec with bigger valves and a decent valve job will outflow them easily..

I Have Built My Share Of Lt1's For My Vettes And F-body's And Trust While They Are A Good Head For 350ci Engines They Are Not Good For Anything More And Dont Make Alot Of Power At The Top. Whenever I ChangeD The Cam I Just Dumped The Lt1 Heads And Went For A Set Of Ported Lt4's Or Afr's

here is the reason i ask. i am working on an engine build with the help of a good machinist. we started gathering parts two years ago and somewhere in the mix my vortec heads got mixed up with a set of lt1's and we didnt notice until it was time to put the intake on. we found the vortec heads but my machinist is saying the look like the same thing and doesnt really want to tear it all back apart to put the vortecs on. i was told that the lt1 head will not work on anything but an lt1 block because of cooling issues, any truth to this? we are going to switch to the vortec heads i am just curious at this point to see if gm actually cast a totally different cooling passage set up for the lt1's

Yes LT1's are a gen 2 small block with reverse flow cooling and they are not directly interchangable because of cooling passages
they can be made to work but not worth the effort

87,
If you notice, the LT1 heads have a water inlet in the front of each head. They are a totally different cooling setup and absolutely will not work on a "normal" small block without a bunch of modifications.