Our local speed shop had a collection of heads like this rather large for paper weights but they do make conversation pieces on the countertop.

This is a pretty typical high RPM failure of these heads, if you don’t need a factory Vortec head to meet class rules I’d go aftermarket as they are beefier castings and better suited to the rigors of competition.

In spite of the plethora of You Tube videos showing all kinds of castings being salvaged by barefoot mechanics in India or Pakistan the success rate on welding iron cylinder heads just isn’t all that great.

Bogie

 

I agree with "Bogie" not real easy to do, but now if you had a 1909 something and can't find another part then it is possible to Weld Cast Iron but if I recall the trick is heating it up and down up and down lowering the temp but still keeping heat to it. Casting something is usually a One Time Shot.

 

These guys can fix it, top name in cast iron repair and undercover race modification of cast iron heads.
They've been around a long time.

Brzezinski Racing Products | Cylinder heads & Intake manifolds (castheads.com)

 

This guys on line ad states he can weld/fix Cast Iron Exhaust Manifolds so I Emailed him 4 pictures of one Ram Horns needing a weld job fix then 2 or 3 days later his reply was he doesn't work on them. My advice is to call him and FULLY EXPLAIN what you want done with what ever you need fix'in .

 

The problem with welding cast iron actually there’s more than one, but the most immediate is that the brittle cast iron cracks along the weld as it weld cools and shrinks. Several techniques are used from bacons the entire head prior to welding then covering it in insulation to very slowly allow cooling. But consider the weld will be 2000 degrees and the general heating will probably be less than 500 F. So it’s still a far piece temperature wise. Add to this the Vortec head is a thin wall casting so it is structurally weak to start with. It really isn’t a racing part to start with. The performance you can obtain from the factory head far exceeds its design strength limits.

A trick that sometimes works immediately after welding is to peen the weld to stretch it as it cools and shrinks.

Cast iron goes through several material phases when heated and recooled this can and does rearrange the molecular structure leading to more cracking, it’s a somewhat a cranky material to deal with its quite sensitive to cooling rates, different cooling methods under control can net quite different properties of the cast iron.

Brazing often works for crack repair and build up but for threading and escorting something dymanic like a rocker stud it isn’t a process I bet on.

The breakage seen in the picture is pretty typical of running the RPMs too high to where the flex turn of the rocker stud combined with the pull of the spring and forces developed if the spring looses control of itself and or the valve exceeds the strength of the iron supporting it. Hex base studs spread the rocking load over more of the face of the stud boss taking some of the rocking motion off the studs threads. A stud girdle also helps this by load sharing across all the studs but there don’t mound with center bolt valve covers.

One huge benefit of aluminum heads is they are weld repairable without a lot of tricks to doing the repair. But aluminum heads being used hard benefit from HeliCoils in the stud threads installed before they are assembled. This has the steel of the threads working against the steel of the HeliCoil instead of the aluminum while the larger outer diameter of the HeliCoil spreads the load into a larger surface area of the aluminum.

Running aluminum rockers reduces the loading on the studs. 7/16 studs are more ridged so don’t impart so much rocking into the stud boss but they do pull pretty hard vertically.

Bogie

 

I have had cast heads welded by Brzezinski and Indy. Neither case worked out. I consider it to be a drag race only repair option and not for endurance or street. A guy local to me does repair on SBC blocks when the starter breaks the block. He has good results and is not doing anything exotic since the engine is still in the vehicles usually. FWIW

 

I had a bolt hole ear break off of a rams horn exhaust manifold when I was a kid. Had a shop weld it back on by pre-heating the manifold and then throwing it back in the oven to slowly cool. Welding took a few minutes, but prep and cool took an hour or more. Anyway, it lasted at least two years, after which the car got headers. But I certainly wouldn't try it on a cylinder head stud boss.

Hey, did any of you guys ever read Grumpy Jenkins' book? He would buy brand new castings from GM and then cut them up, make mods, and weld them back together! No telling how long they lasted, but I was amazed by the race prep that his shop did.

 

Here's what broke off my pass side, IIR its famous for braking on this one.

 

Grumpy’s welded castings only had to last a race or two.

Grumpy and Smokey both had tendencies to write things that didn’t tell the whole story, these guys and many others are or were pretty cagey competitors, if the competition didn’t know as much or more than they did they weren’t above leading folks astray.

Bogie

 

When I was really really young, I got to watch a head being furnace brazed. Holy crap is that an experience.

I suppose spray welding by a reputable shop could hold up, its harder than the parent material. However, it aint cheap and you'd have to build up a fair ammt of material.

 

He’s at the dilemma of backyard repairs on welding on heads is hardly ever successful and professional repairs cost nearly as much if not more than replacing the head.

I suppose the cheapest way to fix it would be to braze the pieces together. Then drill out the threads to install a HeliCoil to return the threads to the original screw in stud size. But while this might get by on a grocery getter I certainly wouldn’t trust on an engine that uses stiff springs and gets wound out even now and then. That’s kind of a back woods, third world country solution but would be iffy even there.

Bogie

 

I JUST HAD A PROBLEM WITH HIS AD SAYING HE CAN FIX/WELD CAST IRON EXHAUST MANIFOLDS, then double stepping backwards of his posted ad saying he doesn't work on exh. manifolds!