Re: 1974 - 232

[farna@xxxxxxx]

YES. All 199/232/258/4.0L blocks are essemtially the same. 85% parts interchangeability! There are some differences over the years, so you may have to mix and match certain parts. 

But for heads:
1. Head bolt pattern is the same for all years. 1964-mid 1980 (model year, mid March 1980 by engine date code) use 1/2" head bolts, from then until 1987 model year (through 1986) use 7/16" head bolts. 1987 4.0L and 258 went back to 1/2" head bolts. Alignment of the head is by head bolts only. V-8 step dowels can be used, but the easiest method of swapping heads is to drill and tap one bolt on each end of the head. Of course the holes on a 80-86 head must be reamed to fit a 1/2" head bolt block. 

2. Shaft (1964-71 and mid 73-74) vs. bridged rocker arms (all other years). Shaft systems have a passage in the block to oil the shaft. Bridged systems oil the rockers through the pushrods. A bridged rocker head can be put on a shaft block as the head gasket blocks the oil hole. Just remember to change to hollow push rods! Mounting a shaft head on a bridged block would require an external oil line. The line as described in the TSB to fix an early six (64-65) oiling problem would work nicely, but there is no real reason to use a shaft head since late model 258 and 4.0L heads are readily/cheaply available. The reason AMC went back to shafts in mid 73 was due to a patent dispute with GM over the bridged rocker design. I don't know how the settlement was reached, but when it was AMC went back to a bridged design for the 1975 model year. 

2A. There is a potential oiling problem on all 1964-71 shaft heads. Basically the oil passage to the shaft is small and can get plugged/gummed up easily, resulting in a reduced and destructive shortage of oil to the rockers. Basically the rockers wera out faster. Unless you're going for a 100% accurate restoration I'd replace the head with a newer one if the rocker shaft is badly worn, but that's just me. See http://www.mattsoldcars.com/techinfo/boltmod.shtml for details on the best fix. An alternate fix involved the external oil line mentioned above, but that looks a bit kludgey at best. If you have an older engine with a good rocker shaft I'd check that bolt out and make sure the work has been done or is done. The problem was taken care of in 73-74 engines. 

3. Port size changed over the years. Early heads have biggest ports, but the 91-05 4.0L HO head has the highest flowing ports even though they are some of the smallest. Has to do with port shape -- a more gradual curve in this case that leads to higher velocity. 87-90 is a close second. 

4. Manifolds generally interchange as long as both are kept together (intake and exhaust). Not that you have a choice -- the intake and exhaust manifolds bolt together through mid 1980. Mid 1980 and later use an aluminum intake with a hot water or electric heating depending on year (1985-88 use electric, possibly earlier) with a separated cast iron exhaust manifold. Port sizes may not match exactly, but a little grinding can fix that. 4.0L engines with their raised ports (all have raised ports compared to earlier engines) present a different problem. 1980 and later manifolds fit, but there is a bigger gap between the intake and exhaust manifolds. The trick is to either use a 4.0L exhaust with 1980-90 carb intake or to make 1/4" thick steel plates to replace the original washers. This is assuming you want to use a carb instead of the EFI. An early bolt together manifold system can be used, but a spacer would have to be placed between them and plates used (or separate and let !
 cold weather drivability suffer). 

5. Accessory mountings changed over the years, and this causes the most headaches! Some accesories used bolt bosses cast into the intake manifold for mounting points. In general if you stick with the accessory package from the year of the intake there is no problem. You'll just have to figure out the right combo of mounts and accessories otherwise. Generally 1964-73 accessories are about the same, and 1974-1979 are about the same. I'm not sure when in the early 80s the accessory mounts changed again, sometime around 1983. Serpentine belt systems are different than V-belt systems also. Just be careful and try to keep the intake close to the year of the car. That's the only advice I can offer! Otherwise you just have to mix, match, and modify until you find a combination that works. 

6. The 4.0L block and head is about 1/4" wider than other models near the top. All other block mounted items are in the same place. There are "wash-out holes" near the right side of the head normally covered by the head gasket on a 4.0L block. These holes are usually so close to the edge of an earlier block that water will seep from them. The fix is to plug the holes by welding, epoxy, or a mechanical plug. Easiest DIY method is to drill them out with a 3/4" bit and drive in 3/4" welch plugs (freeze plugs).... I have seen them tapped for flush screw in plugs too. Plug the holes with water soluble packing peanuts then put a layer of epoxy (something tough like JB Weld) over them at least 1/8" thick, then wash the peanuts out after 24 hours. Welding is best left to a pro! 

I can't think of any other things to consider when swapping heads on the 199/232/258/4.0L family, except to always have a head checked for cracks before rebuilding. You never know... 

Of course the 195.6 head/engine is a totally different animal. The aluminum engine head is iron and slightly wider than a cast iron block head. AL block head can be used on an iron engine but not the other way around, unfortunately. Well, not without some welding work anyway. The right side would have to be widened by welding a piece of 1/4" plate down the side, or machine the side smooth then drill and tap to mount the plate (preferred to welding!). 

On May 9, 2005 Jay Ciampi wrote:

> Will the head fit and work on a 1966 232 block?
> 
> Jay
> ----- Original Message -----
> From: "Joe Wyatt" <jwyatt@xxxxxxxxxxxxxx>
> To: <mail@xxxxxxxxxxxx>
> Sent: Monday, May 09, 2005 1:35 PM
> Subject: 1974 - 232
> 
> 
> > Any demmand out there for a Crank, pistos/rods, heads or intake from a
> > 1974
> > 232/six engine.............
> >
> >
> >
> >
> >
> >
> 
> 
> 
> 
> 
> 
> .


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