may not be common among the V8 crowd but back in my "fast & furious" days of tuner 4 cylinders, I seen numerous people smash 1/2 their electrical wires between head and block when putting head back on. so make sure there is nothing in the way.
Yup!...be VERY careful of that!..
Had a friend who is a good mechanic do a valve job on a Olds 307 back in the 90's,and his customer kept pestering him to get the car finished asap by calling him on the phone repeatedly..(worst thing you can do to your mechanic,BTW)..
He got it back together the same day he got the heads back from the machine shop,and rushed to do so..he was rather irritated at the customer,so he stayed late that night so they could come pick up the car around 6 pm,so they wouldn't be aggravating him the next day..their car has tying up his only lift bay,he wanted it gone,had a lot of other cars waiting to be fixed piking up outside..
Well,the next day the customer called--said "Hey,the car runs great--but the heat wont work!--can you look at it today and see whats wrong"?...
He reluctantly agreed,and had to push another car off the lift he had half apart to get their car inside..it was about 20 degrees out in december..
A quick inspection showed the blower worked fine,but was blowing ice cold..turned out the heater control valve's nylon vacuum line tubing had gotten pinched between the drivers side head and the block!..
..the head gasket wasn't showing any signs of leakage--so he decided to take the wire cutters to it,and snipped it off cleanly on both sides where it was sticking out,and spliced it back together with some rubber vacuum hose..
..and he added a tube of Aluma-Seal to the radiator,just in case...every time that car pulled into his parking lot,his sphincter would pucker up--but they drove it three more years and it never needed anything more than oil changes and a muffler,much to his releif..
I have only done one valve job on an engine with it in the chassis..all I can say is if you have any back troubles at all I'd wear a brace while doing this job,mine ached for weeks after hoisting some 454 heads into the engine bay and bending over the engine for 2 days buttoning everything back up...
I learned how to adjust the valves on that 454 without running the engine on that job,my brother showed me how to turn the engine over to number 1 TDC and adjust certain valves,then turn it over I think 180 degrees,and set the rest of them,going by the procedure in the Motors Manual..
I was reluctant to put the valve covers on till I heard it run,but the engine fired right up and didn't tick at all,so I didn't have to remove them,to my surprise..adjusting the valves the usual way with it running and splattering oil everywhere is my least favorite job on a chevy engine..next to installing a timing cover or oil pan in the vehicle that is!..the suggestion to ditch those rubber end seals on the intake is a good one too,use RTV ,those things are nothing but greif 90% of the time,they'll leak or pop out later on ..
Only other thing I can add is to not use sealer on the head gaskets if they are Fel-Pro Perma-Tourque blue ones,other types like shim steel might need some though..and follow the torque sequence when tightening the bolts..head bolts are about the only ones I ever use a torque wrench on,those and main bearing cap bolts and rod bolts..clean the bolt hole threads good and the both threads before installing them--some bolts will need sealer on the threads,that pass thru the water passages in the block too,I use Permatex non hardening "bear tar" on them..
