“Police Issue” Vortec Heads?

[NightRunner]

Got a question for you guys. My buddy recently purchased a new to him GMT400 (should be lurking around here somewhere). We got a ton of spare parts for the truck, most important being an old set of rusty heads that the seller claimed were removed from a Police Tahoe. The casting number is 12554290, the reverse rotation cooling heads I assume? The seller said that the heads were welded and drilled to correct the reverse rotation cooling, so I’m curious if they’d be a better option to run over my ‘91 TBI heads.

I’ll have some pictures sometime tomorrow for you guys as well

 

[L31MaxExpress]

Got a question for you guys. My buddy recently purchased a new to him GMT400 (should be lurking around here somewhere). We got a ton of spare parts for the truck, most important being an old set of rusty heads that the seller claimed were removed from a Police Tahoe. The casting number is 12554290, the reverse rotation cooling heads I assume? The seller said that the heads were welded and drilled to correct the reverse rotation cooling, so I’m curious if they’d be a better option to run over my ‘91 TBI heads.

I’ll have some pictures sometime tomorrow for you guys as well

Those are cast iron gen2 LT1 heads. Not some mythical police Tahoe head. The police Tahoes had normal 906 or 062 casting heads on them.

I highly doubt being that they are cast iron they could easily be reworked for a traditional engine. Take a picture of the deck side of the head where the head gasket sits and post it.

Although I have seen the LT1 aluminum heads and intake swapped in place of a TPI top end on a 3rd gen Camaro. The coolant passageways were filled and welded and holes drilled in the front of the head into the water passageways to plumb an external thermostat housing into them. The LT1 intake was machined for a distributor and a collar added for the distributor base to fit into. ALOT more work than it was worth IMO.

I have a set of 205cc aluminum heads(bought bare) that now have 2.02/1.60 valves, double springs good for 0.670" lift, guideplates and 7/16" ARP screw in studs that were in the $750 range to buy and build. Even if I had payed someone else to do the valve job and assemble them they would have been under $1K. They flowed 260/180 @ .550 and about 10 cfm more at .650. I am running guide plates and hardened pushrods because I am running Scropion narrow body non self-align 1.7 roller rockers.

I actually bought these heads with a 396 stroker in mind but for now they are going on a freshened up stock 5.7 Vortec bottem end.

 

[NightRunner]

Here's some pictures of the heads. So probably not worth the work to get them cleaned up and ready to install?

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[kennythewelder]

Flip the heads over so we can see the under side of the heads. The side that faces the cylinders, and also take some pics of the ends of the heads. From what you have posted, they don't look like Vortec heads, the intake bolt pattern isn't rite.

 

[joep88cheyenne]

Those look like the heads on my Buick I had. It broke the U bracket on one cylinder and I got it for $100 and it took $2.97 to fix. I don't remember the the year but it was the one that looked sort of like a Cadillac with the truck lid slanted just after the rear window. Could be a 78 or 79 century, but details leave me stranded. haven't been under a GM valve cover since. although I have owned some, just never looked under the covers.

 

[kennythewelder]

Vortec intakes are bolted straight down. Here is a pic.

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[L31MaxExpress]

Those are cast iron LT1 heads. Give away to me is the lack of coolant passageways into the intake. If you flip the head over and look. The passageways for coolant (I circled one of two) are open directly to the lifter valley on a traditional smallblock.

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[NightRunner]

Sorry about that, I didn't really know what to look for on these heads so I just grabbed a couple of quick pictures before they went into storage. I'll see if I can get some pictures of the undersides of the heads soon and post them up for you guys.

 

[kennythewelder]

Sorry about that, I didn't really know what to look for on these heads so I just grabbed a couple of quick pictures before they went into storage. I'll see if I can get some pictures of the undersides of the heads soon and post them up for you guys.

It's all good. As mentioned, they do look like LT1 heads. If the chamber where the valves are is heart shaped, like in the pic that L31 MacExpress posted, those heads are LT1. You can just use the pics that were sent to this thread as a reference.

 

[NightRunner]

So I’m seeing some differences in the passages from what I can tell. Can anyone identify if these are the LT1 heads or if I have something different?

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