Magnum Intake on LA engine?

A few more issues for anyone stumbling on this thread.

Pressure Regulator:

In replacing the broken fuel rail, I noticed it didn't have one and not on the missing inlet stub. Turns out they dropped them after ~2000. I found a federal mandate stopped the practice of circulating fuel to the engine and back since it warms the fuel in the tank increasing evaporative emissions. All cars now (I think) have the regulator built into the pump assembly in the tank, so a single fuel line makes a one-way trip to the engine. I confirmed on ~2001 RAM Magnum truck at PickN'Pull. Cheaper for the manufacturers, though they no longer regulate pressure exactly at the injectors. Of course, the filter must now be inside the tank so no uncompensated drop. I got a 1988 fuel rail off ebay w/ regulator ~$15 total. Ditto for anyone installing an entire Magnum engine. Either change to earlier injector rails or install a separate regulator w/ return somewhere between your last fuel filter and rail.

Magnum heads:

Difficult fit to a 273. The biggest problem is you must notch the block at the top of the cylinders for valve clearance. Not only difficult and tricky, it is a permanent change you can't unbolt.

I also read that Magnum heads often develop a crack between valves. They induction hardened the casting at each seat, instead of using hardened inserts as done to upgrade older heads for unleaded gas. The hardened cast iron is brittle and the distance between valves is short, so it sounds like most will eventually crack. Racers don't care, but us daily drivers need reliability.

Ports:

The 273 heads inlet ports are slightly narrower than Magnum intakes. Since this makes a forward facing step, it will produce turbulence. Great for improved mixing, so one would expect better mileage and torque, but it decreases max air flow (peak horsepower). One could grind a smooth transition (~0.050" each side I recall), but no backing up if it actually degrades performance, and I don't prefer permanent changes to my collector car.

Another approach is to add transition cones inside the intake ports. Perhaps using the epoxy rolls you knead with fingers. One could get clever and sculpt little vanes in the epoxy to spin the flow as Magnum heads do. Another approach is to make sheet metal cone inserts. Perhaps aluminum so less chance of engine damage if they get sucked in. Maybe get real fancy with rotation vanes that almost close at low rpm for max mixing and expand open at high flow. Why didn't auto makers think of this? Likely there are already patents (most anything automotive). If not, I already disclosed it. It should work better than the over-priced plastic "Tornado" cones you put before the throttle body to improve "3-5 mpg" ("your results may vary"). Anyway, diverging since just dealing with a 50 mil step.

My status? Still thinking. Implementation is still at least a year off (many projects). Edelbrock inlet and carb for now. I may install an extra Holley Projection I have between the carb setup and going MFI.