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Pulled old heads off the 5.0 88/Tang. Each old head has a water connection line/fitment at the end of the head (each hole was clogged with rust/corrosion) at the firewall end of the engine compartment. The GP40P heads have no similar fitment/hole in them. What's do we do with that line - plug it?
That pipe is actually used for the thermactor (smog) system.Its the thermactor air crossover pipe.Coolant doesnt travel through that pipe and it also doesn't travel through the passages in the heads where the pipe connects either.Smog pump air is the only thing that travels through that crossover pipe.It gets clogged with carbon due to the combustion process.The following link will explain everything you need to know about the thermactor system. If you have to go through emissions testing in your state/county,the gt40p heads wont accept the thermactor system because the passages arent present in the heads to even be able to run the thermactor pipe and system, but if you dont have emissions testing & youre not running catalytic converters,you can delete the thermactor components all together without issues.The only thing that will occur when deleting this system is,a few codes will be present when running koeo/koer tests,but driveability issues wont be caused.If you run converters and you delete this system, the converters will clog & fail in short order.
Heres the link.Once you open the link,scroll to post #10 & start reading.It explains the thermactor system perfectly.
When you are ready to lay the heads in place,keep this in mind.The head gaskets are labeled with the word FRONT on one end of them.After you lay the first head gasket down,with the FRONT label on the front of the block,then youre ready to lay the second gasket in place,youll have to flip the gasket over in order to position the end labeled FRONT on the front of the engine.Youll notice each gasket has a different side of it facing up now towards the head.It doesn't matter which side of the gasket faces up(towards the head) or down(towards the block).The only important thing is that the end labeled FRONT on both gaskets is on/to the front of the block.If either gasket is installed with the incorrect orientation, overheating issues will occur right off the bat.Backwards orientation causes the rear cooling passages, in the heads & block,to get blocked and coolant comes into the front passages only.The diagrams below will help.Its easy to tell if youve got each gasket installed correctly. Once the head is layed down,look at the very front,lower corner of each head,where the head meets the block,& you should see a squared off portion of the head gasket protruding from the head/block,like shown in the picture below. If this tab isnt visable,youve got the head gasket installed backwards/reversed.
One other important note.Make sure you use sealant on the lower head bolts (the ones below the header) They pass into cooling jackets,so theyll leak if sealant isnt used.
05-09-2018, 12:41 PM
Getting gt40P heads ready to install -
