79 GMC 4.1L 250 Cylinder Head Advise

[79GMCSierra]

Hi All,

After doing a through inspection of my new purchase I discovered the the cylinder head is cracked on the exhaust manifold that is part of the cylinder head.

I believe this head is known as an Integrated Head. Please correct me if I'm wrong.

Anyway I'd like to replace it with a Normal I6 head that has a separate Intake Manifold and Exhaust Header.

My little bit of research tells me that a 78 head might be what I'm looking for. Or as mentioned on another thread a 194 Head. More info on the 194 head would be greatly appreciated.

So what might be your recommendations, keeping in mind this is a California truck. Funny thing is... I just had it smog'd and it pasted with the cracked exhaust manifold.

[79Betty]

If it passed smog i would just weld the crack up. Can't do much with a vehicle after 1974? In cali.

[D13]

You can swap to a non-integrated, you will need intake/exhaust/carb and the carb linkage may not work. Is yours a 1 barrel or 2 bbl carb (take off air cleaner lid, if carb top is round, 1bbl, rectangular, 2bb)? There are no factory 2 bbl non-integrated mainfolds, so you would need aftermarket intake and carb or go to factory 1bbl.
194 head has smaller combustion chambers for a little more compression, but has siamesed exhaust ports so headers don't work as well. All the other non-integral heads are about the same. late 292 have AIR plugs in them so if you have AIR you would need those.
Rebuilt (or at lest cleaned and checked) integral heads show up on ebay time to time for $250-300. That's about what it costs to have a normal head reqworked, before you get the carb, intake, and exhaust. Just make sure you get the right one, and expect to add new rockers / gaskets, etc.
Oh, and buy Leo Santucci's book, version 2. Lots of good info on L6 even though it's heavy on race prep.

[79GMCSierra]

Originally Posted by 79Betty

If it passed smog i would just weld the crack up. Can't do much with a vehicle after 1974? In cali.

Yup that would work, or I may just replace it with a 79 remanufactured head. Thanks for your suggestion.

Originally Posted by D13

You can swap to a non-integrated, you will need intake/exhaust/carb and the carb linkage may not work. Is yours a 1 barrel or 2 bbl carb (take off air cleaner lid, if carb top is round, 1bbl, rectangular, 2bb)? There are no factory 2 bbl non-integrated mainfolds, so you would need aftermarket intake and carb or go to factory 1bbl.
194 head has smaller combustion chambers for a little more compression, but has siamesed exhaust ports so headers don't work as well. All the other non-integral heads are about the same. late 292 have AIR plugs in them so if you have AIR you would need those.
Rebuilt (or at lest cleaned and checked) integral heads show up on ebay time to time for $250-300. That's about what it costs to have a normal head reqworked, before you get the carb, intake, and exhaust. Just make sure you get the right one, and expect to add new rockers / gaskets, etc.
Oh, and buy Leo Santucci's book, version 2. Lots of good info on L6 even though it's heavy on race prep.

It's a 2-bbl. Just ordered Leo's book. Thanks for all your input.

[lilpoindexter]

My '78 California Truck has the crappy integrated head.

[79GMCSierra]

Talked with John from Autowerks today from Iowa and he said any I6 head can work from the 230 to the 292, but may need combustion chamber work. His machined & ported heads go for about $1,100... that's what I paid for the whole truck! Not sure if I'm ready for that. I'm going to keep a lookout for a non-inter-grated head. I'm thinking checking cylinder head gaskets to see what models they fit. Which may be a good clue where to look.

[79GMCSierra]

Originally Posted by lilpoindexter

My '78 California Truck has the crappy integrated head.

I feel your pain! Guess I should have done more research before I pulled the trigger on my new guest in the side yard. Oh well I'm learning...

[beamn7]

My 78 federal emissions C10 has the non-integrated head / 1bbl carb. Truck has been in the family since factory order and has 250K miles on her. Never been apart. Great engines! I would imagine you could swap it to a non-integrated and hope the smog guy is too young to even know what a L6 is but...........that's pushin your luck. I would try and find another integrated head even though they are problematic...

[moregrip]

I'm sort of hodgepodging a few trucks together to make one....long story short.....I started with an integrated head 250L6 motor and am now switching to a non integrated 194 head as a result of speaking with Tom Langdon........in a nut shell, he believed if the integrated head didn't already have a crack, it would soon would.

[Warrens69GMC]

I have a 331184 on a 250ci that I bought in a 1979 nova. You might want to look for that part # .

[79GMCSierra]

Originally Posted by beamn7

My 78 federal emissions C10 has the non-integrated head / 1bbl carb. Truck has been in the family since factory order and has 250K miles on her. Never been apart. Great engines! I would imagine you could swap it to a non-integrated and hope the smog guy is too young to even know what a L6 is but...........that's pushin your luck. I would try and find another integrated head even though they are problematic...

When I took it to the smog shop last week the young guy there couldn't figure out how to shift it. It's 3-sp on the floor. He keep putting it into reverse LOL!!

I see you live in California, and your 79 Chevy C10 non-intergated head passed smog I take it.

Does your engine have these items pictured below. The vacuum valve is attached to the detachable header, so I may be able to find a non-intergrated header with that smog valve. For some reason it rotated the pics when I uploaded them.

Originally Posted by moregrip

I'm sort of hodgepodging a few trucks together to make one....long story short.....I started with an integrated head 250L6 motor and am now switching to a non integrated 194 head as a result of speaking with Tom Langdon........in a nut shell, he believed if the integrated head didn't already have a crack, it would soon would.

Yup like the the machine shop guy said "It's a mistake"

Originally Posted by Warrens69GMC

I have a 331184 on a 250ci that I bought in a 1979 nova. You might want to look for that part # .

Thanks Warren I'll kook for that part number!

Thanks all! Jim

[powerdriver 1958]

When you get ready to remove the integrated head , Have an extra set of hands close . I weighed mine and it was 142 lbs .

[79GMCSierra]

Originally Posted by powerdriver 1958

When you get ready to remove the integrated head , Have an extra set of hands close . I weighed mine and it was 142 lbs .

YIPES!!! Good call!

[beamn7]

Originally Posted by 79GMCSierra

When I took it to the smog shop last week the young guy there couldn't figure out how to shift it. It's 3-sp on the floor. He keep putting it into reverse LOL!!

I see you live in California, and your 79 Chevy C10 non-intergated head passed smog I take it.

Does your engine have these items pictured below. The vacuum valve is attached to the detachable header, so I may be able to find a non-intergrated header with that smog valve. For some reason it rotated the pics when I uploaded them.



Yup like the the machine shop guy said "It's a mistake"



Thanks Warren I'll kook for that part number!

Thanks all! Jim

Yep! It's actually a 78 but yes, it does have the EGR valve and the charcoal cannister you posted in your pics. Difference also though is that the non-integrated heads use a single exhaust outlet manifold whereas the integrated head on yours has the dual outlets. Having said that, you would also need some exhaust work if you were to change it over.

Mines a 3 spd also (back on the column again) and sometimes I think that's the best theft deterrent around. Nobody knows how to drive them anymore!

[79GMCSierra]

Originally Posted by beamn7

Yep! It's actually a 78 but yes, it does have the EGR valve and the charcoal cannister you posted in your pics. Difference also though is that the non-integrated heads use a single exhaust outlet manifold whereas the integrated head on yours has the dual outlets. Having said that, you would also need some exhaust work if you were to change it over.

Mines a 3 spd also (back on the column again) and sometimes I think that's the best theft deterrent around. Nobody knows how to drive them anymore!

Yup every time I've taken it somewhere for service I've had to coach them on how to shift it!