Switching Heads


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By BFOOTER03 - 17 Years Ago
Can I get plug and play a set of ECZ-G heads on my 272?  I drove the truck to work and back Friday 40 miles each way and it ran like a piece of you know what.  It was miswiring  under load and got worse the closer I got to work and home.  Plugs and wires we replaced last year or 750 miles ago.  Pulled 3 plugs and they were covered with oil as I have to remove the headers to get the others out.  Not to mention I was not at all please to see oil on the plugs.  Assume the valve seals are leaking.  Wonder about doing the switch as I have located a set recently rebiult and figure it would be easier and about a cost effective to swap as to rebiuld my.  Thoughts??

Thanks

By charliemccraney - 17 Years Ago
First do a compression check to try to rule out the rings.  I would hate to replace the heads only to find that they are not the problem.  However, the G heads will help you to achive your 300hp goal.  Can you verify that the G heads have been rebuilt.  I find that some people have a definition of rebuilt which is far from my own.

Try an offset box end wrench to get the plugs loose.  It works for me.  They have them at sears.

By Doug T - 17 Years Ago
FoMoCo put G heads on 272's in '57 so there shouldn't be problems  and building a set of heads for the running engine is always nice.  But here are a couple of things to think about:

Compression in 272's is lower with G heads than it is on 292s and 312s.  When you use the current composition gaskets from Felpro you lose even more comprression because they are thicker than the original type stamped steel gaskets. This does not help power.  I would strongly consider milling the heads.  Your will see arguements on this site about how much can be taken off (my vote is for .060 max for an engine like yours) but the more the better. 

Also a compression test or a leakdown test might tell you that you have ring problems but it is not a sure test. If the ring stack is damaged or there is a serious scrape in the cyl wall these tests will show it.  But if the top two compression rings are OK and the oil ring functions poorly then you can still have good compression and leakdown tests but poor oil control,  the bottom ring is called the oil ring for a reason.

While you are into the engine I would check the timing chain unless the motor was rebuilt only 750 miles back.

That is a nice looking truck, why don't you bring it to Columbus next year?

By Y block Billy - 17 Years Ago
You may have just bent or lost a push rod or two, a cracked distributor cap could also cause the mis or a defective condenser, also water in the gas. you didn't state whether you have electronics or points. If you have electronic when the pickup starts to go it could act like that.

I would pull the valve covers and check your lash and for bent push rods, sticking valves, drain the carb and check for water. It may be a lot simpler than changing the heads.

By BFOOTER03 - 17 Years Ago
Gentlenman appreciate the feedback.  I have cooled down and relax a bit so now to the problem at hand.      

Charlie assume the heads have been rebuilt as they are from a buy on the forum but I will double check before buying.

Doug I thought about Columbus this year but didn't fell comfortable about driving the truck that far.  Maybe next year.

Bill still running points.

By BFOOTER03 - 17 Years Ago
Here is the latest and greatest.  Removed valve covers and could not feel or find any bent rods.  Checked compression in some cylinders but reading was only about 35-40.  Does this not seem even to low for the engine to run?  Replaced the plugs and it ran much better but still can hear problems on the passenger side when driving.  Passenger side tends to backfire sometimes going from 2nd to 3rd when puched that was never there before.  What should the lashing be on the rockers?  Should any part store have a lashing tool?
By charliemccraney - 17 Years Ago
You should hold the throttle open when doing the compression check. Disconnect the coil so that it doesn't try to fire when you do this. If it runs, I think you have more than 35 - 40psi. It usually has to turn over a few times before the highest reading is reached.
By pegleg - 17 Years Ago
Bfoot, Wrenches and feeler gages are all you'll need. Possibly a new set of valve cover gaskets. Set the valves at .020 to start with. The back firing indicates crossed ignition wires, intake valves set to tight, or a sticking valve, probably an intake.