400 SBC heads weird casting number

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AuroraGirl

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so i have one head.. appears identical on examination to be 3998997
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but the head next to it, the one i believe would naturally pair, has a number set i cant figure out for the life of me.

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373483 is what makes sense to me

but that yields none. maybe not a casting number?
 

TubeTruck

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It's worn pretty bad. It's 3973493

3973493
400
70-76
1.94/1.50
76cc
 

AuroraGirl

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It's worn pretty bad. It's 3973493

3973493
400
70-76
1.94/1.50
76cc
72 appears to be the date based on the next number set? and wow thanks lol. does that mean the head is shot?
 

TubeTruck

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No, I wasn't referring to the head itself, just the numbers.

I would assume the 72 is the year based on those heads were made from 70-76 but I am unsure how accurate that is.
 

AuroraGirl

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this is a 400 out of my 78 i think. my gpa was going to build the engine back up, he prob got those pre smog heads to make a 400 that was ready to tow kind of thing. because the valve train is in a bucket, im guessing based on context clues

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75Monza

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They should work as a set just fine. If you don't want to rebuild a set of 400 heads and have a good set of 350 heads laying around, just drill the steam holes in the heads and your good to go.
https://www.gregsengine.com/convert... use the Small Block,exhaust side of the head.

As a track engine, I never bother, but for a truck engine that may idle around a bit, I think it is necessary or you end up with stress cracks from steam pockets trapped in the head.
 

TubeTruck

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Your first head is at least matched in CC's and valve sizes. No idea about runner volume, etc., but for a truck motor you probably won't notice.

3998997
350/400
71-73
1.94/1.50
76cc
 

SquareRoot

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If there ever was a more deserving engine than the 400 to be ****-canned for an LS....well maybe the 305.
 

75Monza

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If there ever was a more deserving engine than the 400 to be ****-canned for an LS....well maybe the 305.
Sacrilege! I love my 400's...granted a 509 2 bolt casting no greater than .030 over, lol.
 

Salty Crusty

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If there ever was a more deserving engine than the 400 to be ****-canned for an LS....well maybe the 305.

I've seen a handful of 400's hand some big blocks and even LS engines their butts. Don't listen to all the B.S. hype about overheating and whatnot. Plenty of folks have had great success with SBC400's.

Matter of fact, a 400 would be one reason NOT to LS swap something...

As for the 305, I'd ****-can one of those in favor of a Briggs...
 

AuroraGirl

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I've seen a handful of 400's hand some big blocks and even LS engines their butts. Don't listen to all the B.S. hype about overheating and whatnot. Plenty of folks have had great success with SBC400's.

Matter of fact, a 400 would be one reason NOT to LS swap something...

As for the 305, I'd ****-can one of those in favor of a Briggs...
i got a 2.5hp briggs and scratton for a water transfer pump. think if i make it electronic ignition i can swap it in my truck?
 

peats

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people that trash 400sb's don't know what they are talking about. been running them since '71 with no issues. cheap to build and gobs of torque
 

Ricko1966

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A long rod 406 with good heads on it is a lot of fun. I always drill steam holes, logic being the GM engineers are smarter than me and they thought they needed to be there. And I will gladly swap you briggs engines for 305's tell me when and where.Seriously I'd buy a 305 if it was priced right and close to me.
 
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