I think I already know the answer but Im not sure, will LS3 cylinder heads bolt up to an LQ9/LS1 block or would i need an LS3/L76 block for the fitment to work correctly?

 

LS3 heads are just like the many posts on here involving the L92 version. They can be bolted on 4" and larger bore LS engines, so stock LS1, no.

 

so, hypothetically speaking then, a set of LS3 heads could bolt up to a 370 or 408ci LQ9 and be dropped into a 98-02 f-body? would the same possibility work with LS7 heads? And if the swap worked is the exhaust bolt pattern the same on all LS1/LS3/LS7 cylinder heads?

 

1) Yes
2) I don't think so, the LS7 is in their own little world
3) LS based engines use the same exhaust pattern so your LS1 headers would fit the LS3 heads