My buddies dad gave me these yesterday, which he used on his propane truck. He wanted to get hotter burning heads, so these were up for grabs. Now I believe they are the World S/R tourquers but I want to be sure. They have a few casting numbers one being I-052, another being FU7 and it also has S/R etched in. If anyone can give me any info it would be greatly appreciated cause my lil 305 needs replacing.
Brandon

 

Are they aluminum? Have any photos?

 

No they are iron, I meant to post pics but I guess I didn't.

 

You ought to see if you can find a website for World Products somewhere on the net. With that big S/R in the casting, my first guess would be the same as yours. My money's on that they're S/R torquers. Depending on the casting #'s, they could be either 305 or 350 heads, as they made a different one for each motor. If you're running them on your 305, you don't want to use the 350 ones, as they'll drop your compression way down. The combustion chambers are quite larger on the 350 heads. IIRC the 305's are 58cc and the 350's are 64cc.