How do your bolt holes line up? If the heads/block have been milled & the intake/head faces haven't been milled enough, the intake will sit high on it's own....basically, the intake bolt holes will be higher up than the head bolt holes making the bolts hard to start & the intake not seal. You can mill the intake to fix this. This is the situation I had on a motor & adding the paper gaskets only made it worse (couldn't even begin to start the intake bolts)