Recent content by PRH

Supposedly the target was 450/450.

I’m not saying it would have turned out better if I had taken on that project. In fact, if a customer came to me looking for a build that mild, that made 500hp…….. I would have just built it with more cubes(and it probably still would have gotten a longer duration cam). Even though I nitpicked...

Perhaps. When I did the marathon test(114 pulls) on my 383, switching from 1-3/4 x 3 to 1-7/8 x 3 headers resulted in gains pretty much everywhere. That had unported 906’s.

I realize they had a few days of sorting out ignition woes(which is why I like to start out with “known good” accessories), and most dyno shops probably don’t have many options on hand for Mopar headers…….. but it would have been nice to see what happened to the curve with non-fenderwell headers.

I’m sure most won’t agree with(one of) my takeaway(s) on this one. The heads are “too big”, and the cam is “too small”. The result being heads that produce a TQ peak at an rpm that’s “too high” for the cam duration, and a cam that makes peak hp at an rpm too low to really take advantage of the...

Recut SM intake seat……… 30/45/60/75, mild bowl blend.

My experience with the import LA heads is the guides are usually fine, and typically the seat runout is too. But the way the seats are cut, and where they land on the valve leaves some flow on the table. But I haven’t seen anything I would consider a “reliability concern” on one of those in a...

My preference with Ede heads is to hone the guides and touch up the seats. The guides are usually tighter than I like, and it’s not uncommon to have a few seats where the runout is more than I prefer. Occasionally there is also a head that has a deck finish that isn’t wonderful and could...

“Most” stock BBM passenger car/light truck heads use 14mm x .375” reach, gasketed plugs with a 13/16” hex. Most of the aluminum aftermarket heads use 14mm x .750” reach, gasketed plugs, with a 5/8” hex. Like an NGK BCPR6ES.

Snapshot of the end……. At the top of the sheet there’s mention of swapping vr1 20/50 for Mobil 1 5/40 It would be nice to see the best sheet with the RPM, to see how the numbers compare in the area of the curve below peak TQ.

Admittedly, I did skip ahead several times while watching, but my takeaway was the manifold comparo was the reworked original Torker vs an ootb RPM. Was there discussion/video of porting on the RPM and I just missed it?

And now they’ve got 17 years more wear and tear on them.

Back to the original question… Have you tried running them anyway? I’d say………. There’s likely a 90%+ chance that any high mileage magnum running the roads with its original heads……… is running with at least one crack in one chamber. So, yes……. They’re running them anyway

I was thinking more like right across the wall between the int/ex bowls……… basically right next to the crack. It would be interesting……… but not interesting enough to actually do it myself. Especially since I’m not really looking to increase my cracked iron head repair capabilities.

I’m sure there are tons of success stories of people running the Chinese replacement magnums ootb……… but I wouldn’t risk that myself. The main fear being having some stuck valves in short order. I suppose some guide honing might suffice, but I’d be much more comfortable with some bronze liners...