Anyone using the lq4 373 iron heads?

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Apr 30, 2008 | 09:45 AM

rufretic

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Anyone using the lq4 373 iron heads?

I bought these thinking they were the 317 heads. Anyone using them? Are they any good for a high boost application? I think they are going to bring my compression way lower than I wanted, 8:1 or maybe even lower with my -28 dish pistons. I'm only using them as a temp until I have the money for a set of the 6 bolt etp heads but I would like the car to still put down some good power for now. I should be seeing around 25-30psi

Here's the specs I found with a search.

Casting Number 373
Head: 1999-2000 LQ4 6.0 Litre Truck
Material: Cast Iron
Part Number:
12561873
Combustion Chamber Volume: 71.06cc
Compression Ratio: 9.5:1
Intake Port Volume: 210cc
Exhaust Port Volume: 75cc
Intake Valve Diameter: 2.00 inches
Exhaust Valve Diameter: 1.55 inches

The only positive I can see over the normal 317 is that they are iron, possibly a better chance of not lifting the heads?

How do you guys think they will work?

Forgot to mention they will be on a 402 LSX with a F2.

Apr 30, 2008 | 09:47 AM

hellbents10

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I think they may stay down a bit better. I have always wanted to try em' on a high hp boosted car to see how long you could make the gaskets live.

May 2, 2008 | 07:55 AM

rufretic

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Thanks.

No one else has any info on how these heads work?
Someone has to have used them before?

May 2, 2008 | 12:18 PM

deadmanTA

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They'll work, I just think tha twith a forged lower compression motor I would have just run the stock heads till I could get the betters ones. I got the 317's just to be alittle safer on the stock internals til I get a forged motor.

May 2, 2008 | 01:05 PM

rufretic

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Quote:

Originally Posted by deadmanTA

I didn't have stock and I got these brand new for a good deal so I'm not too concered. I can always sell them, but I needed temp heads anyway. Plus they have bigger port volumes so I believe they can flow a little more air than a stock head as well. I think they might even have a thicker deck, but I'm not 100% on that.

Heres stock specs to compare:

Casting Number 241
Head: 1997+ LS1 5.7 Litre Passenger Car
Material: Aluminimum
Part Number:
12559806 (1997-98) Chambers = 69cc
12559853 (1999-00)
12564241 (2001-03)
Combustion Chamber Volume: 66.67cc
Compression Ratio: 10.1:1
Intake Port Volume: 200cc
Exhaust Port Volume: 70cc
Intake Valve Diameter: 2.00 inches
Exhaust Valve Diameter: 1.55 inches

Last edited by rufretic; May 16, 2008 at 10:49 PM.