Whats the correct CASTING number??
 

Anyone know the correct casting number of the exhaust manifolds on a 72 K20 Cheyenne Super with a 350? My truck has 3932461 but most of the information I have found says these are Corvette manifolds. HELP!!!

Re: Whats the correct CASTING number??
 

I just did the left side on a half ton 72 .3932469 part #.Don't know if this helps you or not.

Re: Whats the correct CASTING number??
 

AASmedic
This Link may help
http://67-72chevytrucks.com/vboard/s...d.php?t=714663

The link also shows a link to speedways smooth one's if you are interested in non-originals
I have always heard that the 4x4's have a straight dump rather that one that curves

Re: Whats the correct CASTING number??
 

Unfortunately no, these are the angled ones. I need the straight dump. Thanks anyway.

Re: Whats the correct CASTING number??
 

What is your goal? I have the reproduction Corvette 2 1/2" outlet manifolds on my Jimmy. That's the route I would go again.

I'm building a 427 for my '69 short stepper and plans are to run the re-pop big block 'vette manifolds on it as well FWIW.

Re: Whats the correct CASTING number??
 

I would like to put originals back on since I have kept the truck as original as possible. Mine are cracked.

Re: Whats the correct CASTING number??
 

The Corvette 2 1/2" manifolds look very similar to the original center dump but will allow for more power. I replaced a set of Heddman Headers and 2 1/4" exhaust with the Corvette manifolds and 2 1/2" exhaust and the "butt-ometer" suggested power was unaffected but noise was mitigated significantly (I used Walker Hemi Turbo 20" case muflers).

The 'vette manifolds are also common compared to the 2" center dumps. Speedway has them for something like $59 each. But you do have to whack the generator mount off and smooth it. Mine have been on my Jimmy since '98.

Re: Whats the correct CASTING number??
 

typically the odd numbered casting numbers are for the left side and even numbered casting numbers are for the right side.

as for corvette vs truck, I would say that high performance corvette equal heavy duty truck.

and the 2.5 inch diameter exhuaste manifolds were for the FI engines

but never say never and if those casting numbers are for corvette they are most likely pretty valuable if not very valueable.

as for the 2.0 " vs. the 2.5" debate it depends on where the peak of your power curve comes in . peak torque may come in sooner and you may not need or even want the 2.5 inch manifolds.

tough call but it may save you a search , hope it helps

Re: Whats the correct CASTING number??
 

How about this? I have two sets off of original Blazers that are 3932461.

Re: Whats the correct CASTING number??
 

Good info. Nb2 is CA emissions? No LH vs RH listed for K pickups or Blazer w 350 - same side to side.
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Re: Whats the correct CASTING number??
 

K trucks used straight dump. Any straight dump will work. I guess it's because the v8 engine sits in the rear position like a 6 cylinder engine is mounted closer to the firewall. The straight dump gives a bit more clearance for the down pipe of the exhaust. Especially for trucks with manual transmission linkage.

Re: Whats the correct CASTING number??
 

Perfect!!!!! Exactly what i was looking for. Thanks!!