Inliners International Forums General Discussion Engines curosity is about to kill this cat.

I have never owned one till now and I am WHY did GM build the 250 with the cylinder head and intake manifold as a unit. Is there any history of problems with this engine?

Al

Yes They are prone to cracking when Over heated.
And Not very good for a HP package.

The good news is not all 250's were built with the integeral heads and you can use a conventional head and your choice of intakes.

Jalopy45 is right, the 250 was introduced in 1967 and had a separate intake manifold at that point. It wasn't until some time in the middle or late 70's that GM went to the integral intake on the 250, so if you find a cylinder head from an early 250 or 230 or 194, it will work and they all have removable intake manifolds.

75 is when chevy started that head on the Novas.
and Like what was said many swap out for the Older heads.

Our 76 chevy 1/2 ton came with an integral head when we purchased it new in 1976. After 160,000 miles the motor was tired but the head never had a problem. Several items to note in defense of this head design. When new, we got 24mpg on the highway w/3 speed Saginaw and 3:08 rear end. I never had a problem with carb ice in the winter and unlike the 2pc manifolds, never had an intake or exhaust gasket leak. True, it was not a performance oriented design but it did what it needed to do for us without complaint. Now entering the 31st year of ownership and the third engine in this truck, (second was an experiment with a V thingy)I am back to an inline 6 and in this case it is a Goodwrench Mexican mfg 292, I am one happy camper. I will never diss the integral head as I never had anything but good luck with it. Your results may vary according to application, mine were OK.

jeff

Thr first question that Gr8 48 Bow Tie asked still has not been answered.
Was it just too reduce cost? Eliminate manifold-to-head leaks?

LOL I like that (Your results may vary according to application, mine were OK. )
The 78 Nova I had ,Had that same head and I never had a problem with it either. But it was just a daily driver for a very short time Then I sold it.

They're not bad, you're just limited on carburetion and exhaust choices. I think Clifford makes (or made) headers for these.

H;

It may have been SMOG related (in 1975).

Tom Langdon would probably know.

Good luck.

GM like Ford and all the rest do things to cut costs whether it be in manufacturing or warrentee work. If you can show a $10 savings per unit let alone a $.10 savings to them you are a savior. GM had to look t all the Ford 6's that had the intigrated manifold from 1960-144" thru the final 200" and saw less steps in construction and assembly time...It's always a compromise for the money. Good Luck

Reo had an integral intake manifold on their OHV sixes. The advantages were advertised as no vacuum leaks and that the manifold was heated it's entire length to promote better vaporization and fuel economy. This was not likely a cost driven compromise.

Thanks for all the info. The one I have has a 2 barrel carb, unlike several others that I looked at with 1 barrel. I suppose it is, whatever will float the boat.

Al

I believe John is correct in regards to emissions. For 1975 there were new standards for emissions that included the cats on most vehicles under 6000 lb GVW. This would also explain why 292s kept the old style heads as they were not available in 1/2 tons at that point.

The decision was probably a combination of all the above ideas. They get a bad rap because you can't upgrade them for performance, (but that only applies if you have that desire), and they are prone to cracking when overheated (and of course that only applies if you let it overheat!) So they are just fine, and I do like the idea of them not having the exhaust leaks as I had a heck of a time getting my stock non-integral setup to line up and seal, and I now have an exhaust leak haha... but I personally prefer the non-integral because adding headers is my next engine mod.