I have 1 set of bbc rec port heads off gen 6 502 mag just back from machine shop all new exhaust valves, guids, new seats new springs retainers and keepers heads where resurfaced and tested also had some mild porting done.selling to go with a set of aluminum heads.800 or b/o plus the ride have all receipts from machine shop have pics also if wanted sold

Will they fit a gen 4 block I'm not sure. Let me know [email protected] Thanks JOHN SR

yes, they will fit.

No, If you have a gen V or VI block any version of heads will work. If you have gen V or VI heads they will not work on a Mark IV block. They may bolt up but I heard you will have problems. I have Mark IV heads on a Gen V block and they work fine. Just will not work the other way.

I started a thread about this in the Tech section. Some say it will work, some say not. Lets see if we get a definate answer.

Ok, all cleared up. You can use the GenVI heads on the GenIV block as long as you use the genVI head gaskets for the proper water passages to line up! Ok....business as usual !