I haven't had a chance to bolt the intake up yet, but I got to thinkin' anyways...If I got my heads milled .030 and I'm running an Impala head gasket (.029 compared to stock .049), that pulls the heads down quite a bit, and seems like it wouldn't let the bolt holes line up on the intake..Any experience with this? BTW, its a stock block that hasn't been decked, and a stock LT1 intake.

 

Mine bolted up just fine. But I was concerned just like you. My heads were decked to get back to 55 CC's after chamber work and I used the Impalla gasket as well. Please post some of your dyno numbers when you get them. Your combination is almost exactly the same as mine and I think I'm still letting some ponies on the table somewhere but need a reference point.

Steve

 

I can't say for sure but it may be close and you might need to elongate the manifold holes. I had a BBC block decked .040 and had to do elongate the holes to be able to fit the manifold. Other than that it works just fine.

 

Cool, thanks fellas, that makes me feel a lil' better And SABLT194, I'll post up my results in a few weeks when its all done.

 

Is that a typo? What in the world was done to the heads that they needed to be shaved so much to get down to near stock combustion chamber size? Running a blower previously?

 

Other than that it works just fine.

If the bolt holes are off enuf not to fit, what is happening to the intake port alignment?

 

if your heads are decked .030, and using a .029 gasket the intake will still bolt up fine assuming the block hasnt been decked. you may have problems with port sealing though and oil getting in the intake runners.

 

"will still bolt up fine....." What good is that? At least that you can easily see. But the "may have problems with port sealing though and oil getting....." and more important from the power output perspective, port alignment, is not as easy to be sure of without proper port alignment checks beforehand. AFAIC, telling someone it will bolt up ok after 'X' amount of stock removal, is basically guesswork and not addressing any potential 'out of sight' problems. I'd rather tell the guy, check it cuz/as YMMV.

 

by "bolt up fine" i meant the bolts will still line up good enough to go through the holes in the intake and be able to be threaded in the heads... as i said the port alignment can/will be an issue which will also hurt sealing

 

Damn, WTF can I do to help prevent bad port alignment? What affect does it have on horsepower/daily driving? I don't want to be adding a quart of oil every week

 

A knowledgable shop will take off an amount off of the intake side of the head when the block side is milled, to compensate. Not sure of the amount for .030, I'm thinking .010. Ask the place that did them. Tell them about the head gasket thickness also.

 

There are LOTS of people running LT1 heads milled this much with Impy gaskets and NO oil consumption problems. As long as the heads are flat milled, the angles will still line up the same.

Anyone with TEA or GTP heads will have the heads milled about the same amount.

As far as port alignment, anyone know what it is like stock? Assuming that it is perfect on a stock motor, and remove .030 from heads and .012 from head gasket thickness, you are lowering the port .042 in relation to the intake manifold. As long as the intake manifold was not "gasket matched" and raised at the top of the port where the injector is than you should be fine. If it was not raised here than the intake manifold is still smaller than the intake port and no "turbulence" would be had.

If you remove the intake manifold on an LT1 and look at how the ports on the gasket line up in relation to the intake manifold, you will see that there is a good "margin of error" here.

On pretty much any engine, if you want the ports to match up perfect, you are gonna have to dummy up the motor after machining, decking and milling with the head gaskets you are gonna run and with the heads marked pass and drivers and match the intake to THOSE heads on THAT motor. I would rather the intake manifold be slightly smaller than the intake port but some want it matched.

NightTrain66

 

There are LOTS of people running LT1 heads milled this much with Impy gaskets and NO oil consumption problems. As long as the heads are flat milled, the angles will still line up the same.

Anyone with TEA or GTP heads will have the heads milled about the same amount.

As far as port alignment, anyone know what it is like stock? Assuming that it is perfect on a stock motor, and remove .030 from heads and .012 from head gasket thickness, you are lowering the port .042 in relation to the intake manifold. As long as the intake manifold was not "gasket matched" and raised at the top of the port where the injector is than you should be fine. If it was not raised here than the intake manifold is still smaller than the intake port and no "turbulence" would be had.

If you remove the intake manifold on an LT1 and look at how the ports on the gasket line up in relation to the intake manifold, you will see that there is a good "margin of error" here.

On pretty much any engine, if you want the ports to match up perfect, you are gonna have to dummy up the motor after machining, decking and milling with the head gaskets you are gonna run and with the heads marked pass and drivers and match the intake to THOSE heads on THAT motor. I would rather the intake manifold be slightly smaller than the intake port but some want it matched.

NightTrain66

 

Thats just ridiculous, there is no reason to take that much meat away from the head unless your going for monster compression. If they are still in the 55cc chamber range then someone did something to those heads they shouldn't have, air powered jackhammer perhaps? Unless they were a former blown car - I still think that is too much meat to remove from an LT1 head without a damn good reason to do so.

If GTP is doing this as you claim, that is another fat mark against them. As for TEA, I haven't heard anything particularly great about them either.

 

Are you talking to me or SabLT194? If your talking to me, Lloyd did my heads and recommended i mill them .030 and use an impy head gasket, improving my quench and bring me to ~11.8:1 compression. I don't see why thats ridiculous, would you care to explain? (no flame intended, I'm just learnin' this crap) The heads were formerly just stock untouched heads BTW