SBC Heads

[Ole Blue 68]

Hey all,

Got a hold of some heads today, casting #3973487 which I believe go back to the early 70's LT1. Think they're worth a trip to the machine shop?

Thanks,

John

[gentry69]

hi i looked up the casting for u they are: 71-72 350 used on 71-71 350 lt1' s and they are 75cc didnt say what valves are in them are they 202/1.6 or 194-1.5s

[gentry69]

to answer your ? i guess if it were me i would

[Ole Blue 68]

Thanks gentry, I can probably get them done for about $150 or $175.

[gentry69]

hey no prob glad i could help.

[bighead]

Sell them to a vette guy and buy some good heads. The performance of those are ok but some vortec's or darts are better and would cost less brand new than to fix the old ones. They will need hardened seats installed, maybe guides, valves, surfaced or ??? Just MHO, bighead

[Ole Blue 68]

The Darts I've seen run about $600 or $700.

[gentry69]

imo i should of bought a new set of darts cause i bought a pair af camel backs for $400 and then spent another 400 beefing them up but i did the works on them. if u just want a good set of heads for a stocker and dont really want to spend a hole lot i would just use the LT1s but if your going to go the hole nine yards then yea prob would sell them and try to buy a newer set of heads

[Ole Blue 68]

That's just it, you can get pretty crazy on a set of heads.

[Bowtie67]

If these where the performance heads off of the early 70's 350 they where exceptionly prone to cracking and one of the lowest performance heads that GM produced as a performance head, basically pieces of $hit. Sometimes a set of good used heads are a deal, but other times when you get done having them sent to a machine shop and they require any type of machine work, new valves or new guides you could end up paying more than if you just purchased a set of new heads.

Back to your question about taking thm to the machine shop, deffinately, at least have them checked for cracks...

[71-longbed]

im running those heads on my stock 71 350 .... in my opinion .. there fine heads ....i have over 250k miles on that engine ... they seem to last the test of time (knock on wood)

but if your looking for higher compression .. ditch the 74cc chambers and get yourself some 64cc heads ...

[gentry69]

u can also have the machine shop mill your heads down to at least 67 cc prob get by with 64 i cant remember what i started out with but mine are now about 60cc and it didnt cost much

[Ole Blue 68]

What about 882 heads? I see a lot of these being sold but they seem to have the same specs as the 487s.

[gentry69]

you can go to www.mortec.com and check out all the casting #s and descriptions

[Ole Blue 68]

Thanks!

[olblue81]

Originally Posted by Ole Blue 68

What about 882 heads? I see a lot of these being sold but they seem to have the same specs as the 487s.

Back in the early 90's I picked up a set and had them port matched and pocket ported. I kept the valves at 1.94/1.50. This was supposed to be the hot setup for very reasonable dollars and keeping the compression 87 octane friendly.
Go here http://chevyhiperformance.com/techarticles/41598/
They have a database of flowbench tests on heads, both GM and aftermarket. You can see the 882 has the best .400" flow numbers of the first 4 factory castings even the L98's. But look at the vortec castings and see how much better they are. 23 cfm at .400 over the 882's.

[Ole Blue 68]

Good info!

[olblue81]

I should also add that no matter whether you go with new heads or have the old ones rebuilt, make sure you spend the money to add screw in rocker studs. My 882's have had several come loose. It is possible to fix on the motor, but in reality, it's better to pull the head to repair.