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[MATT2007]

I am going to be puting a new LIM gasket in my car i was wondering if i decied to pull the heads off and mill .0050 off them would I get enough horse power to pay for the $60 extra in gaskets and the $70 to get the heads done
also wondering if I put the 3400 intake on is it the same gasket kit as the 3100 or is it different

[bszopi]

You won't gain any HP by just milling the heads, no matter how much you mill them.

As far as the gaskets being the same between the 3100 and 3400, it depends on the year if the 3100. If its the older style (93-99), then no. If its the newer style, then yes.

[MATT2007]

so would a kit for a 3400 work if not what will and dosent milling the heads rasie compresion I have done it on some v8 for frinds and l4 and it raises compresion why would a 60v6 be diffirent

[IsaacHayes]

What car/engine/year do you have? Hard to guess what you have and recommend what will work without knowing.

[MATT2007]

1996 chevy lumina with a 3100

[bszopi]

Sure, milling the heads will raise compression, but not enough to be noticable on these engine (or really any engine for that matter). When you start milling the heads, you start bringing in more issues that you'll have to address, like piston to valve clearances, lower intake alignment, etc. For the insignificant gain you will achieve, its not worth the $$ or the potential problems that could arise.

[MATT2007]

all right now I under stand

[IsaacHayes]

Since you have a 96, you have roller rockers (so the larger LIM will clear the rockers fine) and could swap the large port intake manifolds on from a 3400. You'll need the Lower and Upper. You will need to use the lower intake gasket for your year heads (96 for small port 3100). Not the 3400 or large port 3100 LIM gasket. Fel-pro makes metal LIM gaskets too.

The upper intake gasket of course will have to be the new style

I think you have the screw type coolant fitting in the LIM, so you could go with 97-98 chevy lumina minivan LIM and UIM and the coolant pipe fitting and EGR should bolt right up. You can use a 2000+ style UIM, but you would need to use the 2000+ EGR too as it bolts on differently but will work with your wiring, and you may need to get the EGR exhaust tube to work/reach it though.

You could also use a 99+ LIM but you'll have to tap the coolant port to screw in your screw coolant nipple. A quick couple of searches and you can find more info about the subtle differences and what you will need.