were can i find the specs on my head
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Member
Joined: Feb 2004
Posts: 370
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From: MN
Car: 91 rs
Engine: 250
Transmission: 700r4
Axle/Gears: stock??
were can i find the specs on my head
the head casting number is 3986339 and it's a 71 307/350 74cc head. i would like to know valvue size and other specs were can i get these
Joined: Mar 2000
Posts: 43,187
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From: Littleton, CO USA
Car: 82 Berlinetta/57 Bel Air
Engine: L92/LQ4 (both w/4" stroke)
Transmission: 4L80E/4L80E
Axle/Gears: 12B-3.73/9"-3.89
From http://www.mortec.com/castnum.htm
3986339....71......307/350......74cc chamber
But you probably already knew that.
Since different valves could be put into the same castings, you can't always tell what you have just from the casting #'s. Having been put on both 307's and 350's is all the more reason to believe that. However, I wouldn't be surprised if they're 1.72/1.50" wonders.
Best way to find out the details is to get it from the heads themselves - measure valve diameter, cc the ports, measure flow on a flow bench, etc.
3986339....71......307/350......74cc chamber
But you probably already knew that.
Since different valves could be put into the same castings, you can't always tell what you have just from the casting #'s. Having been put on both 307's and 350's is all the more reason to believe that. However, I wouldn't be surprised if they're 1.72/1.50" wonders.
Best way to find out the details is to get it from the heads themselves - measure valve diameter, cc the ports, measure flow on a flow bench, etc.
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Joined: Jul 1999
Posts: 18,457
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From: Loveland, OH, US
Car: 4
Engine: 6
Transmission: 5
They're garbage.
It hardly matters how profoundly they stink. They're garbage. Not worth putting any effort or money into.
I've literally thrown dozens of sets of heads of that general sort in the trash, when it was inconvenient to take them to the scrap yard.
Measure the valves with a micrometer if that's important to you somehow. But regardless of what size they are, they're garbage too..... unless somebody stupided out and put Manleys in them or something. Highly unlikely to say the least.
It hardly matters how profoundly they stink. They're garbage. Not worth putting any effort or money into.
I've literally thrown dozens of sets of heads of that general sort in the trash, when it was inconvenient to take them to the scrap yard.
Measure the valves with a micrometer if that's important to you somehow. But regardless of what size they are, they're garbage too..... unless somebody stupided out and put Manleys in them or something. Highly unlikely to say the least.
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