305 to 350

[T Anderson]

I know the header has nothing to do with the power steering pump. I've changed pumps before. Its a Chevy small block. It was in a mustang. The headers were hacked up

 

[MadOgre]

Never played with a 283, but the 305 manifolds have the rear most bolt farther back than on a 350. That's why the exhaust manifold gaskets on the block have the double bolt hole on one of them. So they can be used with a 305 or 350.

Interesting.

I have swapped 305 manifolds onto 350s and vise versa. I have never ran into that issue.

Im pretty sure headers are not 305 or 350 specific. They would have to be if there was a different bolt pattern and I have never heard of this before.

Do you recall exactly what motor in what vehicle and years ?

 

[DoubleDingo]

Never played with a 283, but the 305 manifolds have the rear most bolt farther back than on a 350. That's why the exhaust manifold gaskets on the block have the double bolt hole on one of them. So they can be used with a 305 or 350.

I have never seen a 305. I had to investigate on the good old web and saw that newer 305 heads have the extra hole so a regular manifld can bolt to it. Some people had a machine shop drill and tap the hole closer to exhaust port on their passenger side head so a regular manifold can bolt up to it. I find it very interesting when engineers do stuff like that. A 305 is a small block, why have an odd hole on the head. Is it solely to be able to identify a 305?

 

[DoubleDingo]

I can see what you mean about the rams horn style, but this is entirely different.

Just different because of the 305 head being different. I need to keep the bolt hole in mind when I look for 305 vortec heads for my 283. Thanks for the heads up.

 

[CSFJ]

I think it is. I ran into it on an '84 k10 with the manual trans, 305 small block. Only the passenger side head. Not sure what other models it showed up on, but it seemed fairly common. When I ran into it, the only other manifold I had layong around was exactly like it.

Found a pic online. Notice the odd spacing on the bolt holes by the manifold dump.

You must be registered for see images attach

 

[DoubleDingo]

Ever since I was a kid in our auto parts store, I have wondered why the exhaust manifold gaskets had some with the extra hole. Mystery solved. I learned something today, now I can go home...lol...

 

[MadOgre]

Ever since I was a kid in our auto parts store, I have wondered why the exhaust manifold gaskets had some with the extra hole. Mystery solved. I learned something today, now I can go home...lol...

Ya me 2 lol