Rectangle port head intake side - picture?

[scuncio]

Hi all,

I am trying to figure out whether my set of 840 heads has been ported on the intake side. The ports look larger than my 291s. Can someone please post a pic or measure the thickness of the wall between the ports?

Thanks, Tony

[SuperNovaSS]

It should be fairly easy to tell, are the ports smooth or as cast? Maybe it would be easier if you posted a picture of your heads.


Jason

[scuncio]

I will get a picture. The ports seem smoother than the exhaust ports so I assume they have been gone over to some degree. Should the 291 and 840 castings have identical port dimensions?

[scuncio]

A few months late but here goes:

[markjohnson]

It's kinda hard to tell from a photo but it does kinda look like they do have some port work done. Your intake ports look pretty smooth and don't have that rough "as-cast" texture to them. Intake ports should be pretty much exactly the same between 840's and 291's but 291's are slightly superior because of their 1.88 exhaust valves while 840's only have the 1.72 exhaust valves. But hey . . . . . since the valves are out, just stick your finger in the valve hole and feel the short short side radius (the floor of the port), if you can feel a sharp edge just a little ways down from the valve seat than they probably have not been ported. If the port floor feels smooth without the sharp edge than they've probably had at least a little port work done.

[scuncio]

Thanks Mark. Good idea to check for the sharp edge. I'll dig them out today and look.

[Fast67VelleN2O]

Yes those heads look like they have been lighly ported or gasket matched.