Mopar Stge IV head picture

What port do these come with???

Thank you for the recognition.

As the 906 has more potential than the 452, the Stage V has more potential than the Stage IV. Plus the Stage V has a much better exhaust port than the 906.

Chuck Millen at Best Machine and Dwayne Porter both ported a set of Stage V's back in around 2004 for myself and one other gentlemen. I believe the info is easy to find inthe tech archives by searching stage V. Also the exhaust port is improved as well (it's so shallow and tight radius ....it's amazing they could do much with it at all) and I believe the IV and V share the same exhaust port.

The Stage IV's as cast were not much better then the 906 however additional material was cast into the port roofs and built up on the floors to enhance the rather severere short side of the 906/452's. This was first done with the IV's and later further improved on the V's. Out of the box not much but when well ported they do start picking up around .400 lift and in the right hands the Stage V flows on par with a mildly ported Edelbrock.

The Stage V makes an awesome 500" stroker head, the improvements in the mid lifts add a lot of torque and extend the RPM range compared to a 452/906 that is ported to flow as well at say .550/.600, you just can't get the same mid lift numbers without the short-side radius improvements, not without some pretty extensive/expensive roof mods.

It's been about 30 years since I held a Stage 4 but I think they also cast them to reduce the pushrod pinch and required maybe a .100" offset intake rocker? Sorry, I'm trying to remember that far back but I think the V also had a smaller pinch but it didn't require the offset due to enlarging/bridgporting the pushrod pasages in the thicker as-cast port walls.

I'm sure Experts will chime in and tell me if my memory still serves...or not!

my iv's cracked through the valve seat

Hello; Is that seat cracked on the exhaust?? I have one here to on the exhaust. It's a thin area under the short turn were there is very little metal for suport!!!! Another better idea form MOPAR!!! They never did have a clue what there were doing!!!! Have you had it fix yet, and how was it done. Thanks

This is going back 25 yrs (testing my memory here) but I ran Stage V's on my 500 inch 440 in a chassis car at 2400Lbs with a Glide. I spent all my money on the short block and had to scrimp on the heads (there weren't many options anyway back then). I believe with just a gentle port opening and some bowl work we got them flowing in the 280-285 range. I did use a Crane offset intake rocker and 2.14/1.81 valves.
The difference on the V over the IV in addition to the better exhaust port already mentioned was the oil passage was smaller dia so the pushrod was able to move over a little if I recall correctly.

It was a great combo, it would run 9.50's/9.60's at 140 with a 1.28 60 ft. Through the years I have seen guys with better heads not go any faster. I think the port velocity must have been way up there and it just plain worked.

stage v's tuned up by dwayne porter

intake exhaust
.1-72.5 .1-57.2
.2-148.2 .2-117.1
.3-212.2 .3-168.2
.4-256.3 .4-200
.5-278.7 .5-202.5
.6-290.2 .6-204.9

Here's my intakes with 2.19" intake valve (which I think enhanced the mid lift flows (265 cfm @ .400 is really pretty decent):

Stage V's (ported)

.100"--75.6
.200"--159.4
.300"--221.7
.400"--264.6
.500"--280.
.600"--285.5
.700"--289.9