E-150 351w Headers?

[Chupacabra]

Hello this is my first post here, I did a search for this information and couldn't find any definitive information on the topic.

I just purchased a 1995 E150 with the 5.8 L 351 V8.
The pre-purchase inspection found a small leak somewhere in the exhaust manifold warranting replacement of the manifold.

Most of the online information for these motors is within the hot-rod/ muscle-car community, and is influencing me to approach this fix as an opportunity to upgrade the headers and exhaust to allow the engine to breathe a bit better.
Although all the information I find is focused on total-raw horsepower, not necessarily drivability and low-end torque that will improve the dynamics of my van and even add some MPG.

My questions for those of you in know are:

Is this a worthwhile upgrade for improving power and driving dynamics of a 4x4 Van?

Please help me understand "shorty headers" vs "long tube headers"?

Will any of the aftermarket offerings even fit within the engine-bay and chassis of the 1995 E-150?

Thanks in advance for any advice or information!

Cheers

[86Scotty]

Not an easy one to answer. Many have had trouble using aftermarket headers on 4x vans because the front driveshaft gets in the way.
I would be prepared to have to have brand new headers modified by an exhaust shop to fit.




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[carringb]

Personally, I wouldn't do it. I had a '94 E350 with the 351. Shorty headers all would have required some modifications to fit. Headmen makes some long-tube headers, but they have thin flanges susceptible to warping, and probably would not fit a 4x4.

The 351 responds very well to better breathing by removing intake restrictors and doing a cat-back exhaust. So well, cooling become marginal. I ended up also upgrading to the 460's radiator, which required a new shroud, and fan-hub extension.

As for your current leaky manifolds... I'd just repair and reinstall. Once they are machined flat, they should not warp any further, so it should be a one-and-done deal assuming you use good gaskets.

[arctictraveller]

Be sure to check all the exhaust studs. On later models they tend to corrode and break off. Once your missing a few, leaks are not far behind. Possibly, your manifolds are still ok, it's just a bit loose, but I can't say for sure that the 351's had this issue.

[carringb]

Yeah, 351s had a tendency to break studs too. Once you have a leak, I think machining flat is prudent, since the leak can cause more warping. Of course... sometimes swapping out the broken studs is enough of a labor savings, its worth a shot.

[BroncoHauler]

The biggest challenge on my 351W (Bronco) used to be the header bolts which didn't take long to loosen up with the extreme thermal cycling. I got to be pretty good at swapping in new header gaskets until I switched over to Stage 8 locking header bolts. Haven't had an exhaust leak since.

https://www.stage8.com/


Herb

[arctictraveller]

Replacing the studs in my 5.4 solved the leaking problem, but getting the old studs out is a bit of a chore. I ended up taking it to a muffler shop with lots of experience in removing them. He welded a bolt to each broken stud that allowed it to back out, the thermal shock probably loosened the stud a bit too. If you suspect a less than flat manifold, but don't want to remove them, Remflex gaskets will most likely seal just fine. https://catalog.remflex.com/category_s/1.htm