I'm putting together a 455. I have a 73 block with 67 430 heads. I've been reading some threads about 67 heads being prone to cracking....what I'm unclear about is whether they're talking about 67 400 heads or the 430 heads. I'm trying to determine whether it's a good idea to have these 430 heads rebuilt or if I should put that money to better use and buy a new set of heads. Any insight would be appreciated!
I do believe its the 67 430 heads as I ran into having a set checked before I started anything with them. Sure enough 1 of them had cracks. So now I only have 1 good big port 67 paperweight.
Use that one for porting and know that industrial rebuilders weld those and put back into service everyday.
The cracks are between the valve springs, the castings are thinner in these area and there is coolant behind there. I would not weld and re use them, throw them in the scrap pile. To give you an Idea how bad they are the last time I needed 1 head it took 13 cores to get 1 good one, the time before that it was 11 cores to get 1 good one.
I've been thinking about shipping that pallet full you have this way. It wouldn't be an issue to do those with a full warranty, that stuff is no big deal. I'd be more concerned with trying to cultivate and create a market for selling that many in a timely manner. "We" shipped out nearly 150 heads a day used in a much harsher environment, without failure. Also did rare musclecar castings weekly as well, but charged up the wazoo for it. All that being said it would be extremely risky to trust a local shop not set up to do this all day long. There's a reason that the largest rebuilders only send stuff to a handful of places.
So what is the repair for the thin casting in these area's that crack with low factory spring pressures so that area will take larger spring pressures. I have no problem with welded cast iron if done correctly but how do you make all those thin area's thicker? Weld the cracks but all those area's are still thin right? Hence why buick solve the problem in 1970 up castings.
I got a 2985 head in service in now that was cracked between 2 or 3 springs can't remember, but its only got mild springs, I still worry about it tho, all the more reason to go aluminium on it I rekon
Mine were pinned on each end and sewed up, can't speak for longevity as its only seen 2500 to 3500 miles so far
This is a 1970 head, some people say they crack because they are a larger port but the problem area is above thin water jackets not ports.
I've been told that the 2985 head is desirable because if the larger ports. Sounds to me like you guys are calling them boat anchors....
Most of the problems I have seen is with the 1109's but I think most of the earlier heads had issues of some degree.
Pinning is often used to stiffen thin areas, so is adding some beef to it. Some of these I-6 heads out there are not very well supported to say the least. There's millions of heads in service way worse than these. Some have the span of the deck surface trussed up...and will go out to do another 500k miles at heavy or full throttle. It isn't uncommon to build up 1/2" beyond the original material, even that far past the finished machined surface prior to cutting it back down. Another way of viewing it would be that some heads are "re-poured" again. You're definitely not going to zap it inexpensively with a "special" wire or rod and get it to live. The process can be quite involved, therefore one set at a time isn't worth it for anyone. Fixing it isn't the challenging part. That whole business is structured differently than a walk-in, a-la carte style small machine shop. Fleet operations are paying for the cost of an entirely rebuilt, ready to bolt on head so they can get their vehicles back out making $$. The repair work is simply the first step in the process. Cores can be worked on before they even receive them, to keep the costs and lead times down on the common castings. Keep in mind that fleet customers and major rebuilders don't complain about a few hundred $$ labor hidden in the total bill or even the cost of shipping, as those engines can be quite expensive. Add that to the fact that each fleet vehicle is viewed as a $$ making machine and you can see why the general public never hears about the "magic" of welding heads, haha! Blocks can be $5-10k easily... Why would you even talk to someone about an auto casting? It can be done though...
Just reading this thread, and it scares me. I've got an original 430 that has about 120,000 on it and it has never been pulled apart. It still runs perfectly, and it gets beat on fairly regularly. But it is eventually going to have to come apart. Since I live in Canada, shipping up cores from the US becomes incredibly expensive in a hurry, is there another head I can use in case these ones come apart? So far there's no evidence of leakage or cracks or anything. There's no antifreeze in the oil. How would I know if they're gone? Does the car smoke? Or is crappy grey oil the only way to see it without pulling the covers off? Are all 1967 430s susceptible to this problem or was it only a limited number?
Pull the valve covers off time to time and look for a sludge build up between the springs along with coolant etc like in the attached pictures. This engine had about 100,000 original miles on and the anti freeze killed all the bearings in it.
If you look at the way it cracked, it's high stress crack of pushing side ways not front to back loads. Its a valvetrain geometry problem, not high pressure of springs or factory springs. I suggest to a friend that has several big port 430 heads. He had me make a list for him to send to a machine shop. Number one thing, crack for cracks, number two, sonic test whole heads, including between valve guides, then if good, proceed to valve guide work and enlarging valve pockets if desired to stage 1 spec's. And so on and so on. Known what to look for and do is a must in big port heads.
X2 So other than adding material, what sort of preventive measures can be taken to avoid this? Independent engine oil cooler and a bigtime radiator? I imagine this is in part due to high temperature. A big cam needs stronger springs right? Would a roller cam and roller rockers be easier on the heads?
You can't do anything to avoid this, they are thin from the factory and more spring pressure with a roller or bigger cam might only amplify the problem. The spring pressures are pushing down towards the head and the rocker pedestals below where they crack are getting pushed away from the head but that said there are still a lot of these heads that are still in service that have not cracked so maybe its a plant process related deal or something along those lines because they are not all cracked after almost 50 years.
Ben if I were you I would wait for a nice set of 1970-71 Iron Heads show up that have been worked and buy those or ask around for them. Then buy them for a lot cheaper than hat you would have to put into them in cash. I have seen nice Iron heads on here for the right price. Already worked and ready to go. That or just wait long enough and sometime Aluminum heads do show up. Not often but they do. That's just my thoughts though. Good Luck Man, Jesse Z.
