Chevy Nova Forum banner

1 - 6 of 6 Posts

·
Registered
Joined
·
75 Posts
Discussion Starter #1
I got some sbc heads from a old hot rod guy he said they were power pack heads. Can't fined the cast#. They have the big valves. # 3878487x anyone know and are they good heads.
 

·
Registered
Joined
·
20,109 Posts
I got some sbc heads from a old hot rod guy he said they were power pack heads. Can't fined the cast#. They have the big valves. # 3878487x anyone know and are they good heads.
Powerpack heads were small valve small closed chamber 283 heads. Should have a raised square pad with a triangle coming off the top of it. This would be on the front head face. Not sure of that casting number though.
 

·
Premium Member
Joined
·
901 Posts
487x

A quote from the cited corvetteforum:

"Of the earlier, 76cc heads, the 487 is supposed to be the more desireable casting. It was also the casting core for the early LOW compression hi-perf engines (ie Vettes, 71-72 Z28s). I don't know that an X head would be of any significant improvement over a regular 487 head.
But regardless, when it comes to big chamber (~76cc), lo-comp SB heads, the 487 is among the most desireable castings."

In essence, the 487X is more than a 76cc open chamber smog head.
 

·
Registered
Joined
·
75 Posts
Discussion Starter #5
Thanks for the info they do have Manley guide plates and screw in studs with good springs and stainless valves.
 

·
Registered
Joined
·
139 Posts
487 and 487x heads are supposed to be the best of the "smog heads". But, they are extremely prone to cracking in the exhaust seats. So check them carefully with the valves removed or have them magnafluxed before buying any.
 
1 - 6 of 6 Posts
Top