349 CI on the cheap

whoops im sorry its a 318 stock stroke 0.40 and has valve reliefs on the pistons as for the headers i can switch over too them but i was really kinda wanting to stick with the manifolds seeing as how i already have them and the exaust is all new i'll want to change the motor over to a 349 but kinda tight on funds right now but seeing how i'll need to fix my heads for my current prob i was thinking i'd be a step further im gonna look in some wrecking yards and look for the 302 cast heads or would i need a different type of head also a ruff guest of what this would cost [ just for the head work and correct thickness head gaskets ] im also running a 904 with stock converter and 323 gears
thanks terry