425 heads

[Guest oldtimer]

i can't remember if it was the 455 or the nailheads. i read or heard something about not wanting the smog heads (the ones with air injection tubes). any clues on what i'm talking about ?????? ('cause i need one).

[The Old Guy]

The 71 up 455 has holes in the heads that correspond to the AIR system on the intake manifold. If you have a 430 or a 70 455 ,you will have to plug the end holes in the later heads or you will have problems. I tapped the holes with a 3/8 -16 tap and screwed in some brass screws until they bottomed. I then cut them off and filed the surfaces smooth . This seems to work just fine.

[Guest oldtimer]

i just found a 425, it has a smog pump and looks as if the injection tubes go into the head (instead of the exhaust manifold).

[Guest]

In '66 Buick added the AIR system to the California nailheads. For more info on the AIR system on nailheads, the '66 Chassis manual covers the CA version. I put a '66 425 block and '66 CA 401 heads into my 65 GS. I plugged the holes with set screws and painted.<P>Dave

[Guest]

I too run 'smog' head with the injection tubes. They're from a 73 riv GS and now power my regal race car into the 8's in a 1/4 mile with NOS. The tube have been plugged and have not been a problem ever since I drilled and tapped them 7 years ago. any questions can be sent to me at buik455@aol.com

[Guest]

Must be 72 and up heads cause my 71 doesn't have air holes.