Considering new heads.

[OrangeCrush1970]

I think my heads have seen their day and I am considering a swap. My engine is original to the truck and my question is whether or not different heads would de-value the block? I know if I threw on some HO’s it would be a different story, but Im thinking VORTEC. Also, would I be able to burn 87 w/ a set of updated heads, or would this require further mod’s to the fuel system?

If some of you are wandering why I think my heads are worn out, it is b/c they were re-worked in 2000, at the same time the engine was rebuilt, and since had about 45k miles put on them over the last 8 yrs. I am burning oil as well as a bit of coolant. I know these symptoms point to a possible head gasket leak, but I have been using the ol’ Marvelous Miracle oil and what little amount of smoke I had from the pipes as diminished. I have also been replacing my spark plugs about every 6k due to excessive carbon / oil deposit on my # 7 & 6 cylinders. What do you guys think? Take me to school!

[cdowns]

you can put new heads on the old block after you completely rebuild the block //that way you get your moneys worth

[bigvinnie]

if your motor is stock, I would think adding smaller chamber heads alone might not be a good idea.... a cam change would be required in order to make the most of the higher compression, assuming your stock heads are 72 or 76 cc, vs. the 64 cc of the vortec head.

If you're not planning to change the cam, I'd rework my stock heads or buy a set of Dart Iron Eagles with the same cc as your stock heads.

[OrangeCrush1970]

Check out my sig...I state my engine build there, Im not going to build it again yet as it's only got about 45k on the 2000 build and the mechanicals are all heavy duty.

[c10crazy]

I say bolt on the new heads since your motor has relatively low miles on the rebuild.

[sneakysnake]

You might want to run a compression check also. It might show or help pin point some other problems. Ive always heard dont put good heads on an old motor, something about the better compression with old worn bearings will cause it to sling a rod quicker.

[OrangeCrush1970]

Originally Posted by sneakysnake

You might want to run a compression check also. It might show or help pin point some other problems. Ive always heard dont put good heads on an old motor, something about the better compression with old worn bearings will cause it to sling a rod quicker.

I agree, the block has never been bored, so there's no telling what kind of shape the cylindars are in after 38 years and who know's how many miles. The pistons were new at install (2000 build)....it's a shame Im not ready to build this engine again, that's just not in the cards for me right now. I can't say enough about how well the engine runs and pulls, it's the symptoms that are showing up that have me worried.

Thanks guys.

[streetstar]

If the new heads you were thinking about had a smaller combustion chamber, it would bump the compression a bit and may cause you to need more octane --- however , that is alleviated somewhat if you use aluminum heads vs. cast iron (you should be able to run 1 numerical CR point higher without detonating vs. an iron head assuming everything else is equal.

So if you have 76cc truck heads now, you may be able to run 64cc alloy heads without a problem

[bigvinnie]

Based on your build specs, I'd probably bolt on the vortecs if your compression checks out OK, and see if the z28 cam was bumpy enough to make use of the higher compression... if not, a cam change is not too pricey or difficult, just a bit of PITA to do without pulling the motor.

[Billla]

I'd look for the source of the smoke before spending any $$$. Could be seals - and that's an easy on-the-car fix.

[OrangeCrush1970]

Thanks guys, appreciate the help-

Rob

[OrangeCrush1970]

the I.D. # on my heads ended w/ 411. What does this mean?

[gmc67swb]

One other thing if you go with vortec heads ,you'll also have to change the intake. but i'm sure you already know that.just thought i'd make sure....running stock vortec's on mine now .they do flow good ,i'm just looking for a little more power so i'm gonna to upgrade to edlebrock 2.02 vortec heads and do a cam swap as well...lots of luck.....

[chevychase]

Originally Posted by OrangeCrush1970

the I.D. # on my heads ended w/ 411. What does this mean?

Are you referring to the casting #'s? If so, I checked mortec.com for last digits of 411 and 911 incase it was hard to read and come up with nothing. Double check the casting #'s, they shoud be 6 or 7 digits, go to mortec.com and do search for your #'s or post em up here.