Manifold Hitting the Block
Okay, here goes:
A reman engine can be other than your specific year. Most likely yours has later heads on it, say '73 and later. These have extended exhaust port surfaces on them, some may be drilled for air injection systems, some may not.
Early style heads/exhaust ports:
Later style heads with larger exhaust port surfaces and air injection holes drilled:
The issue is where the driver's side manifold drops down to it's exit- it is, out of necessity, very close to the cylinder head in order for it to clear the steering column.
This can often result in clearance issues with the head's #7 exhaust port surface.
The solution, as tempting as it may be, is not to grind the head- there is a water jacket not far beneath the surface, and if you cut into the jacket, the head is junk. Yes, I've done it. If the interference is extremely minimal, you may be able to barely touch the offending area with a grinder- but no more than that. A bit can also be taken off the manifold, but again, don't get carried away- too much can weaken the manifold and it can crack after a few heat cycles.
Try a nice, thick exhaust gasket- sometimes it gains you just enough room to clear everything.
Make sure you get 273/318 specific gaskets, the larger port 340/360 gaskets can have sealing issues on the 318 heads/manifolds.
If that's still not enough clearance, then you need to get a "header flange"- a piece used by guys who fabricate their own headers. They're typically 5/16-3/8" thick.
Sandwich it between the manifold and the head (no gaskets), and your interference issue goes away. You *may* need longer exhaust studs & bolts for this.
The last option would be to use a '73 and later manifold, made to clear the newer heads.
I have also run into a similar issue when using 340 manifolds on Magnum engines. I had to use the header flanges on that, too.
Okay, here goes:
A reman engine can be other than your specific year. Most likely yours has later heads on it, say '73 and later. These have extended exhaust port surfaces on them, some may be drilled for air injection systems, some may not.
Early style heads/exhaust ports:
Later style heads with larger exhaust port surfaces and air injection holes drilled:
The issue is where the driver's side manifold drops down to it's exit- it is, out of necessity, very close to the cylinder head in order for it to clear the steering column.
This can often result in clearance issues with the head's #7 exhaust port surface.
The solution, as tempting as it may be, is not to grind the head- there is a water jacket not far beneath the surface, and if you cut into the jacket, the head is junk. Yes, I've done it. If the interference is extremely minimal, you may be able to barely touch the offending area with a grinder- but no more than that. A bit can also be taken off the manifold, but again, don't get carried away- too much can weaken the manifold and it can crack after a few heat cycles.
Try a nice, thick exhaust gasket- sometimes it gains you just enough room to clear everything.
Make sure you get 273/318 specific gaskets, the larger port 340/360 gaskets can have sealing issues on the 318 heads/manifolds.
If that's still not enough clearance, then you need to get a "header flange"- a piece used by guys who fabricate their own headers. They're typically 5/16-3/8" thick.
Sandwich it between the manifold and the head (no gaskets), and your interference issue goes away. You *may* need longer exhaust studs & bolts for this.
The last option would be to use a '73 and later manifold, made to clear the newer heads.
I have also run into a similar issue when using 340 manifolds on Magnum engines. I had to use the header flanges on that, too.
