which would be better
All of this is build dependent and any head can show a gain or loss. Building a engine with a Magnum head in mind can yeild more power than a letter head and vice a versea.
Arguing and pointing out which head does what in a ported form is a moot point and may very well not fit this particula build of the OE poster. His build is vauge to start with and this argument is close to pointless and may only confuse the OE poster.
1W&C, DGC has very good points on which to argue. In a maxed out for, the LA heads win, but is this allways good for the design of the engine or a simple street car? Is a bigger port allways wanted?Needed? A must have?
We both know that answer is a big NO!
Sometimes a smaller port and valve head is exactly what the engine needs/wants even if the flow is down vs another head.
The only advantage the roller cam has over the MP Hyd. cam is that friction is down a slight bit and if it is on a Magnum head, a "LA" roller cam now has the extra intencity and lift from the rocker ratio change.
Though, I do not think this the case in the create engines which out power the "LA" create engines with a zero difference between them in the shrt block.
Thing you must see is that when building around a head, you able to compensate...that is as long as the flow is there.
so you want quench??? use quench dome piston already..
You want increased ratio?? buy a set of rockers.
Now some might say...''oh, but the magnum has'em stock''-1.6
Oh yeah??? well I don't know about you, but I run a decent sized cam when I'm building power and those non roller pedestal rockers don't have rollers last time I checked, so I guess those just useless to me unless I want to trash my guides and simply wear sht out.
And port volume?....better cc those magnum's cause 155cc on j head aint big when it comes to 340-360cid...btw notice the higher roof by looking at the port window on a j head? think that has a lil to do with why they might flow more?, yeah.
I said before and I'll say it again, the magnum heads were designed with smog requirements and fuel injection in mind, closed chambers help this, but also can impede flow=shrouding.
smaller port window-'sometimes the case' is either a mix matched combo in which air speed from a smaller port window is only a band aid for poor blue printing/too big a carb etc.. and usually ends up as a trade off else where in the power range.
As for low lift flow ...I didn't know high 190's @.300 & 230's and high 240's at .400 lift was crummy low lift flow, I must have missed that in my mopar engines book...lol
