I am currently doing a 5.3L carb setup in my 77 nova. This is my first LS swap. But I'm an ASE certified mechanic and this is not my first swap in a car where something wasn't original.

My question is I have a 2001 iron block that came with 706 castech heads so I'm swapping them out before they give me problems as i will be beating on this setup once running. I have a set of 799 heads that came off at 05+ 5.3L engine and from what Ive read the bolts were all the same length on the newer heads. All the bolts (other than the top smaller bolts) were the same on my 01 heads except for two under the valve cover on the outside. Do i just need to run the 05+ bolts/studs? Im going ARP either studs or bolts.

Ive been searching on here and online for this answer and figured i make a first post on here about this issue.

Also would it be better to run LS9 MLS gaskets or the LS1 MLS? Heads will be milled to raise the compression to where the 706 heads were. Just wondering if there was any advantage strength wise with the LS9 over the LS1 MLS head gaskets.

 

The type of bolts depend on the year of the block, not the year of the heads.

 

What he said on the bolt/studs. Block is 2001, so 2001 bolts/studs.

On the gasket, if you are going for compression, go with the gaskets that most closely match your bore. LS9 gasket (4.100") is going to be gigantic on a 5.3 (3.78") bore. LS1 gasket should be a 3.910" or so and what I would use in your situation not knowing your cam selection. If you aren't going too wild on cam, you might consider some thinner gaskets to boost compression a bit more and improve quench. That being said though, in the realm of cheap, good, factory parts that work without doing math, the LS1 gasket gets the nod.

 

ok awesome thanks for the help guys!