Let me know what you find.
See post 39 and the link. I just read some of it but I'm not sure Ryan is 100% correct.
I'm substantially sure that the W7 head in part at least was developed by Kent Ritter when they had that C Econo car, the other part of the they being Webber and I can't think of his first name.
My memory of the conversation I had with Ritter was to NOT buy the W5 and move right to the 7's and not look back. Unfortunately, by the time I got around to getting the heads you couldn't sell your wife in prostitution to get a pair of them. They were like hens teeth and IIRC Chrysler was moving on from that platform to the 8's and 9's, which AGAIN was ignorant because they should have seen the market for stroker engines going through the roof. Had the kept the 5 with some simple updates the guys with the W2's could easily upgrade. And they'd have a head today that would be a damn good head.
Or, they could have went ahead and killed the 5 and made enough of the 7's to keep the price down. Chrysler was FLUSH with cash and they could have sat on those heads and let the market come to them. Piss poor management.
IIRC, the 7 was developed out of the 5, which is why they are fairly close. I remember when I got my 5's and started looking them over. Everything Ritter told mew as true. The valves were too short, so they drop the spring pocket. That blows. When you raise the roof you can't get it high enough without breaking through the spring pocket. Look at the 7 and it takes longer valves and the spring seat is much higher.
The 5 doesn't have the port raised nearly high enough, because of the above.
They usually had a butt load of porosity, and you have to have a cast iron gut (and a TIG welder handy) to fill in where needed.
The 5 is an 18 degree head while the 7 is a 15 degree head.
The 7 has the rocker shaft hold downs are already milled off and actually designed for a Jesel style shaft system. The 5 doesn't, and when you mill the stands down, they get a bit thin.
That's some of what I remember off the top of my head. I don't think (can't be sure) that Arrington had the corner on those castings.
Funny story. My dad wanted to go to the track and watch some road course stuff at Portland International Raceway. It was only a couple of miles from his house. Anyway, he kept riding me, telling me there is a bunch of MoPar sponsored cars down there.
I wasn't interested in FWD 4 banger junk, but he wore me down. We show up and it's the Archer brothers and another guy who I can't think of his name.
Arrington was there with them. After qualifying I went to the pits and hung out with the Archer brothers. I think one was named Tommy I think. They were looking at the plugs and we got into about a 20 minute conversation about plug reading and it was a great lesson. For free!
About the time we finished up, Arrington came over to lash the valves. When they took the valve covers off they were pretty tight with what you could see, but the heads on that engine appeared to be W5's.
They were fast. If you want to know the year, you can probably find it if you look it up. It was the year Walter Payton was there, and the goof ball Willy T. Ribbs.
Ribbs hit everything including the hot dog stand. He never made a clean pass all day and he clocked Payton pretty early in the race, IIRC.
He was a joke. That had to be in the early 1990's.
Just a little useless trivia.