Fastback71

So i tried looking for the casting number towards the front of each head but the alternator bracket and A/C bracket are completely blocking my view on both sides. So i went to the driver side Head and in the center of the head the only casting numbers I could see was 409 147. Can this tell you if they are 5, 6, or 7 heads?

another quick question.... I noticed I have pcv on both valve covers thats linked to my air filter housing then a tube down to the passenger exhaust manifold. does this mean i have EGR or it just positive crankcase ventilation to help it breath/vent a little better? and if i replace the filter housing to after market can i just get away with putting aftermarket breathers on both valve covers for ventilation?


thanks for your time

allyolds68

7's or 7A's, can't help on the other question

Fastback71

is the 7 or 7A worth keeping if I just wanted to port them a little bit and match them up to a good cam/intake/carb combo?

Fastback71

well son of a bitch! i wiped off some old grease/oil front the front of the head and got the right sunlight and looked between the cracks and low and behold i have #7 heads lol. time to do some research...

ihengineer76

The #7's are a good head. If you are going to port them anyway, there is no reason to switch to a 5 or 6. Most will argue that there is little flow difference between them assuming valve size is the same. These heads have the same size chambers as 5 and 6 also. If you are switching cams, adjustable rockers are a nice upgrade as well.

Fastback71

good stuff thanks for the info!