SBC head question

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Looking at buying a 383 from a friend of mine to swap into my '92 GMC Jimmy ( S10, not fullsize )  I pulled the valve covers off of it and the casting number is 3947041 with a date code of K 8 - 8.

Here is what I have found so far from doing some Google searching....

Made on 11-8-68
They came with either 2.02 / 1.60 or 1.94 / 1.50 valves
64 cc combustion chamber
They will not have hardened exhaust valve seats -- this is where my main question is.

The engine was in an older Monte Carlo SS that my friend picked up last fall, so neither of us know much history on the engine.  He pulled the 383 to swap in a big block, so the stroker is just laying in the garage waiting for me to buy it

The engine has been ran before, I have no clue on miles or age, but I do know that it has been used.  I don't however have any idea as to if they had hardened exhaust valve seats installed.  I don't want to risk any damage, so I might just pull the heads off for inspection before the install.

Is there any way to know visually if the exhaust valve seats are hardened?
If they are not hardened, how much ( ballpark ) does it run to have hardened seats installed?

[Disturban]

I would just sell those heads on ebay or craigslist and use the money to get some vortecs...then you dont have to wonder. As far as I know there is no way to visually tell if they are hardened seats or not...I could be wrong? To have hardened seats installed I would think would run no more than $200 for the pair and I do believe they are pressed in. If the motor is in fact a 383 and you have alittle extra cash I would not skimp out when it comes to the heads (Vortec heads) is probably bottom of the line I would run on that motor...383's like to breath so if ya can afford something better like AFR 210's by all means go for it.

[TOOLMANN72]

if you look close around the valve you can see a line where the head was cut out and an insert was pressed in if it has hardened seats installed and it would be on every valve .

[Squirell]

just sell them go give terry rosebush 400 bucks and get a set of darts

[Disturban]

just sell them go give terry rosebush 400 bucks and get a set of darts

Thats what I am saying...those heads are probably worth $400 or $500 to somebody looking to restore a numbers matching car, then use that money to buy a set of better flowing heads.

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I have also been told to watch out for very high compression with these heads on a 383, so I should tear the heads off and see what pistons are in it, cam, etc...

I can get a better set of heads then these for $400?  That sounds very nice!  I have heard a few people mention the Vortech heads, will they actually flow better then these? 

Not too sure though if I would want to sell these, they might be better then the heads that are on the 350 in my '94 S10 Blazer.


Bottom line is that I don't want to go through a small block swap and have less then 300 hp.  The trans will come out and be rebuilt with good stuff also, and I know I will break other things as well, but it won't really be an off road truck, so we will see how the axle holds up to my heavy right foot 

[Disturban]

Bottom line is that I don't want to go through a small block swap and have less then 300 hp.  The trans will come out and be rebuilt with good stuff also, and I know I will break other things as well, but it won't really be an off road truck, so we will see how the axle holds up to my heavy right foot 

Dude I am running a 355 with TRW 9:5.1 pistons 30 over, forged steel crank, afr 210 heads, edelbrock rpm intake, holley 750 and a comp cam 268H in my Trans am and on the dyno it made 425 at the crank. I was shootin for 450 and could have got it with 10:5.1 pistons but I chose to run less compression so I could also use a 150 shot of spray and be safe.

With the same compression ratio and cam I am running with Vortec heads (Use bee hive springs) you should make close to 400hp easy!

And yes even if your heads have 2.02 valves the Vortec's will out flow them with 1.94 valves. However there are vortec heads you want to stay away from. The 58cc heads are 305 heads (Stay away) The HD 906 casting has a exhaust seat that restricts flow. You want the 12558062 vortec's!

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One more thing that I forgot to mention.   The heads don't have the stock rockers on them anymore.  They have roller rockers on them and guide plates.  The guide plates are Manley, and my friend thinks the rockers are Harland Sharp.  Also, I don't quite know what they used for stock valve springs, but the ones on the heads have a second spring inside the main spring.

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I talked with my friend a little more about the engine yesterday...

My friend (Ted) was told that the engine was just rebuilt and only has about 100 miles on it. He was also told that the engine needs premium, but he didn't ask anything else, and hasn't seen the guy since.  I guess the car came from West Branch.

When he got the car home, he said that it didn't seem to have as much power as it should have and he found the timing off. He set the timing and it really woke up. He also adjusted the roller rockers and said that it made a huge difference in power also.

So, the engine would have about 150 miles on it right now, hopefully enough to avoid any damage if they used the wrong parts. With the guy suggesting premium and with the roller rockers and guide plates, I would hope that he knew about the valve seats and had them replaced.

[scooter08]

if they are 041 heads have them rebuilt if you don't want to buy a new set they will work

[millser]

pull the oil pain to see if its even a 383 might be stock

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Well, the bonus checks from work will be cut out on Friday so I will be picking the engine up!!!

Without knowing anything else about it other then it does run right now and runs good, do you think it would be worth $600?

I will pull the heads and oil pan and see exactly what I will be working with as well.  This is going to be a project that probably won't see the road until next summer so I have as much time as I need  to get different stuff if I need to.