ive heard it gives significant power gains. is this true? and if so would i be able to put the 350 heads on the 305?

 

Which 305 heads? They will bolt on and are a direct replacement. However, there are 39573957397 versions of 350 heads. Most of which have larger chambers than your 305 heads so you will suffer a loss in compression ration. Every point lost in compression is roughly 4% in power. Assuming you have a 305 your best bet would be to find a set of 416 or 081 heads. Both were 305 heads that respond well to porting. Both have 56 to 58 cc chambers which will keep your stock 305 in the mid 9.X compression ratio. If you do go with a set of 350 heads, lets say mid 90's vortecs, you would want to have them milled to reduce the chamber size (64cc stock to 5X).

 

the only reason i considered putting the 305 heads on my 350 is because there are some people telling me it will bosst the compression and hopefully getting more power. but i have yet to find out what heads they are yet because im skeptical on doing it and was trying to find out if the rumors were true or not.

 

What cylinder heads castings #, are you referring too? Are they going on a 305 or a 350?

Occording to the flow# posted in the stiky treads, the 305 heads flow less then the 350 heads, probably due to the smaller valves used on the 305.