Hot Rod Forum banner

Couple of head questions

1K views 8 replies 8 participants last post by  cdminter59 
#1 ·
Is the exhaust seat in the picture hardened? I don't think it is, but want to confirm.

Also, I have a set of fully ported Sportsman II heads that I was planning on putting on but my machinist is trying to talk me into some "fantastic" stock rebuild 487 heads, which are what the truck left the factory with. Engine is a 355 with a Crane Energizer 274h06 cam. He says the 487s will perform better? I call BS, the Sportsman heads aren't ideal for my combo but have got to be way better than stock smog heads. Opinions?
 

Attachments

See less See more
1
#2 ·
They look like open chamber heads most likley hardened seats.. If it's going in a truck stock casting would prolly be a better choise. The bigger runner on the sportsman might take away from your low end somwhat Depends on a lot of other info like compression. Gear , tranny, exc. if the stock castings are done rite no reason not to run them. But again depends on rest of combo..
 
#3 ·
487 is a good head. On "the list" (popular among circle track at the lower levels where stock heads are required). 487X is purportedly the L-82 head, found in late '70s Corvette. No verification. Anyone?

All stock heads made after mid-72 have induction-hardened exhaust seats. Any engine equipped with EGR, anyway. That includes 487. "Heavy duty" (C-30 and bigger) may have "inserts" for seats. LPG engines certainly do.

Sportsman head is a decent head for a 400 and torque. Better for mild performance than torque on 350 (IMO). If you want power over 5,500, use the Sportsmans. If you want power UNDER 2,500, use the 487s.

Jim
 
#5 ·
Heads are the originals that came on the truck. March 1971.


I'm leaning towards the sportsman heads because I already have dished pistons and the 76cc chambers will drop my compression way down. I like torque, but I also want something that will make power above 3000 rpm...
 
#6 ·
Heads with induction hardened seats will show a bluish tinge to the metal surrounding the exhaust valve. It will also prove to be very resistant to abraision compared to unhardened cast iron.

The 487s were dogs back in their day and they do not have hardened exhaust seats they predate that requirement. I know GM pushed them as a performance head, but they do a poor job of it, even subpar for their day and silly by today's standards.

The Sportsmand II heads don't wake up till ported which your's are, they aren't up to current standards of fast burn chamber heads but they are vast improvement over the 487 or 487X.

Bogie
 
#7 ·
That certainly doesnt look like its induction hardened; as bogie said, it will look blue-ish. As with any old casting, its hard to judge by year, since they're often overhauled several times; but in '71 you wouldn't have had a hard seat. By the time you put hard seats in the exhaust side of those hi-po turds; you're left with an expensive set of pedestrian heads that somehow the circle track and GM parts guy mistakenly believe are performance heads. Sell them to a circle track guy; use the Sportsman II's. Or, sell them both and buy some more modern heads that fit your application
 
#9 ·
I think they are a 1971 head. So unless a previous owner has hardened seats install no they aren't hardened. Check out these Pro-Filer aluminum heads. http://www.profilerperformance.com/racing/cylinderheads/sbc-23-degree. The best way to purchase heads is to buy them bare and have your machinist to check them over and install the valves, retainers, springs and locks. You always need to purchase valve springs that are recommended for the camshaft.
 
This is an older thread, you may not receive a response, and could be reviving an old thread. Please consider creating a new thread.
Top