Hey guys, i've got a 5.3 thats about to rollover 200k and i think i have either the dreaded castec's or a bad head gasket.. When i get around to fixing it i'm gonna buy a set of 243's and have them milled and rebuilt. I'm also gonna do a cam swap with timing set,lifters,pushrods, and all the other essentials. I have a little problem though. I had my headers welded to my ORY to solve some bad leaks i had.. Well i know i cant leave the headers bolted to the heads and swap them so i was wondering if i unbolt the headers from the heads would i be able to swap them and the headers not cause too much of a problem? I know it would be easier to swap the heads if i could remove the headers but with them being welded i would have to cut them off and i'm not doing that until im ready for new headers..

All help is appreciated.

 

Its a tight fit and kinda have to muscle them around but it is possible as long as you loosen up any flanges you might have so it allows you to move the headers around with the y-pipe , but it is possible I've done it ...

 

Hard to say. The locating studs for the heads may cause you some issues if the headers won't move. Other issue I'd be worried about is if the bolt holes will line up with the new heads properly.

 

Hate to say it but the $20-30 it would cost to have them re-welded if you cut them would probably be worth saving the fight of not cutting them for the swap.

 

I had'nt even thought about the header bolt holes not lining up properly, im glad i posted!! It does seem like leaving the headers on would cause alot of headaches during the swap.. i might just invest in a new set of SS headers for my swap and do it all right..

How much would i have to mill the 243's to get a 10:1 compression ratio on stock pistons?

 

Saws-all... Going to be a pita getting to lower head bolts with headers right in the way..

 

Just disconnect the Y pipe from the exhaust pipe unless it is welded also. Even it is is I would cut 1 pipe rather then both, to see if that allows you enough room to work.. That should allow you to possibly drop the headers and Y down enough to do what you have to do.. Other wise, cut the Y pipes at a area with no curves in it, then just band clamp them back.. Unless you plan to do the exhaust again..

 

On my 5.3, my 243's are milled .030 and I'm using a .040 head gasket. Put me at 9.9:1

 

Great help guys.. i guess i could just unbolt the ory at the stock exhaust location and drop it down but i would probly have to remove the trans crossmember to lower it..

If i wanted to use the stock mls gasket then i would have to mill the 243's probly .035" to make my compression 10:1.. would i have any alignment issues with the intake manifold or headers if i milled them .035"-.040"?

 

everytime i swap heads i leave the exhaust intact. when you do one side at a time move it over and down a little , put a head on, then repeat for the other side.