I have also been considering removing the manifold and putting some nice big headers on my 1995 Roadmaster. I haven't opened the tool box yet, but all my research indicates that most small block headers will be a REAL hassle, and will require a lot of fabrication and headaches. There is also quite an issue with the EGR systems. If you just slap on any old pair of headers, the EGR will start throwing codes and the check engine light will stay on until you remove it from altogether from the PCM. Deleting the EGR system would also require some fabrication to plug the holes where the exhaust gas enters the manifold. Other than that the engine should run fine, but a check engine light blinking drives me nuts even if I know there is nothing wrong. The only direct fit headers I have been able to find for the 94-96 B Bodies are to be found at Clear Image Automotive :: The Clear Choice For Performance! which seem to fit the bill, but are kinda pricey. It have even read that tight tuck and shorty style headers have fitment and heat issues, not to mention having to fabricate a way to connect them to the cats. I personally think I am going to save up and spring for the Tri-Y's. I imagine some good flowing quads will really liven up the Roadmaster version of the LT1, and paying more for something that fits right makes sense to me. However, I have not been able to find ANY dyno information about the Tri-Ys on the LT1 B body, so I guess I will just have to find out the hard way.
The heads will physically bolt to it, but they won't work. The LT1 used a reverse flow cooling setup, so the block was machined a bit different. How ever, Vortec heads are basically direct copy's of the LT1 iron heads, and will work great on a Gen I SBC. However, you will need a vortec intake manifold(bolt pattern is different), then you will need to address the distributor. You either have to machine the vortec intake to fit the larger dist of the B-body, or use one from a truck. using one from a truck, presents it;s own issue. The reason for the larger hole on the B-body's intake, was so the dist could slide in past the cowl. You have to put the intake and dist in together, and work them in with a truck style intake manifold hole.
Jardin: That is a post for a whole new thread. I can talk your ear off on that subject.