OK, I'm looking at potentially pulling the heads. I really don't plan on doing anything to them other than having the broken exhaust manifold bolt removed. Additionally, I figured that while I had them off, I'd upgrade the valves springs and install a set of 1.6 RR.

So my engine is bone stock internally.

I have a CAI, 160* Thermostat, and removed the catalytic converter.

I'm looking at adding the

1.6 rr's
Long tube Pacesetter headers
removing the CAI and installing a LS1 lid setup.

So how much HP should I see. I know this estimation isn't an exact science and some engines may pick up gobs of power and some not much, but how much on average would these mods make?

Thanks!

 

I think anywhere from 15-25whp would be the norm.

 

While you have the heads off consider getting them milled .010 and a thinner head gasket to give a little boost in compression for HP.

 

Resurface the heads should be considered while they are off. Need a nice clean flat surface for sealing on the block. Alittle compression would come in handy but dont go too high. May need to start using 93 oct and retune for it if the compression gets too high. The stock small cam keeps cylinder pressures high.

For abit more money consider a valve job on the stock valves. Should net some flow and few ponies there.

I would think exhaust/lid when combined with a tune can be fairly significant gains. 25whp sounds plausible.

 

LT1's love compression...going higher will build power nicely.

You should be using 93 octane already and wouldn't need a tune for higher compression...

 

Agreed.

 

Def get some mill work done to the heads- if nothing else a simple valve job to make sure everything is kosher.

If you are going that far, why not consider throwing a cam in there too? If you go with 1.6's you'll need new springs anyway and with getting the heads milled you are probably looking at a day or two turnaround getting them done- perfect time to throw the cam in there.

But that's just me. BTW- get yourself some band-style clamps for your headers- they are worth every dollar and you will thank yourself the day you have to take them back off.

 

True, should be using 93 but even stock cars benefit from a tune. Add some compression and bolt ons, a tune will free up alittle bit of power.

 

I don't disagree, I'm simply stating it isn't necessary. Just an opinion, of course...

 

I dynoed at 288 with minor bolt ons... ported heads and threw 1.6 rockers and dynoed 316/327 not bad.

 

I'd expect 285-310rwhp on a 1.6RR/Full Exhaust/Bolt-on M6 car.

 

I agree... I dynoed the numbers in my Sig with no tune and Cutout closed. I now run the Cutout open and got a tune... hoping for 325