SN95 track car, 5.0 or 4.6? A question of high RPM reliability and block splitting, not horsepower

So from all that I've read from different sources, it seems to boil down to this:

5.0:

lighter, smaller, narrower (easier to install headers as a result), simpler

super cheap and easy to work on and modify

average reliability for a Ford V8, which is pretty decent, although the block isn't particularly strong if I were to really beat on it.

4.6:

more complex in every way, more difficult and expensive to work on and modify

must upgrade early ones to PI heads/intake to get decent power, head bolts are expensive

heavier by almost 100 pounds, super wide

cheats on math tests, used to sell meth for extra money

basically indestructable and will run forever

Seems like I'd be a lot happier with the 5.0, but the longevity of the 4.6 may outweigh all it's negatives, since I'll be driving the engine pretty hard, as will my wife (who I'll be teaching how to autocross in this car) and probably my dad as well once or twice.  That reliability would probably be enough to push me towards the 4.6, however the 5.0 is so cheap I could always just grab one from a junkyard Explorer and slowly build it up in my spare time for whenever the first one wears out.

Apexcarver said:

That out of the way, if motor is staying stock, mod motor all day every day for longevity. Saw lemons teams running 4.6 2vs many races and teams running 5.0s changing engines mid weekend as a habit. The 4v should be as reliable, but more power. Biggest problem might be timing chain guide wear.

That's where my head is going.  I think I would like the 5.0 better and it would certainly be easier to modify and build and all that, but I'll be on a $2020 budget so I won't have much money for mods anyways.  The engine would probably stay stock except for maybe cheap intake/headers/exhaust.  The 5.0 may be more "fun" all around, but the 4.6's reputation for reliability is winning me over the more I read about it.  And I'll be autocrossing this close to monthly, and my wife will probably be driving it from time to time as well, and when I have extra cash I'll be doing some HPDE with Chin Motorsports at Sebring (my parents live there, makes for an easy trip).  So the engine will see a lot of hard use.  Not looking forward to working on the heavy monster, but I think the 4.6 would be the smarter option.  

Honestly on a budget it is going to be the rest of the car around the motor that I'd be more worried about, both have decent reputations in near stock trim. 

SVreX said:

Javelin said:

Or go plan C and buy a 96-98 Cobra and have both power and a great block. There's one for sale on the forum for Challenge money. 

Where?

I have not seen this

In the for sale section, green, rusty. I wanted to buy it for it's low mileage motor but it's nowhere near me. I'll try to find it and bump it.

I suspect that the reason that the 4.6s are more reliable than the 5.0 in the Lemons series is that they're newer so the junkyard engines are just in better shape to begin with.  In my head you were looking into building a motor.  For what you're looking at doing I suggest you get the nicest, lowest mileage car you can find in your budget and not worry about which engine it has.  I've never built a 4.6 so I have no idea what the power limits are on them or what the cheap options are to extract more power out of them.  I have seen them break rods when over boosted but every engine has a part that's going to let go first when you start adding power.

The 5.0 engine has a lot more aftermarket support and is much cheaper to make way more power on post challenge.  

I’ve owned many a Mustang and this is a no brainer to me unless you can score a 99-04 4.6 for challenge money.  I wouldn’t touch a 96-98 4.6 GT or a rusted out cobra, but that’s me.  

Not that it really matters but the k member is different between the 4.6 and the 5.0 in the mustangs so if you get a car with say a v 6 you may need to do a k number swap depending on what v8 you decide on. 

I vote to keep the W124 and build that. Great chassis with bolt on performance from other benzes. Stock IRS. A nice turbo on that m103/m104 should have you in SN95 power range. 

buzzboy said:

I vote to keep the W124 and build that. Great chassis with bolt on performance from other benzes. Stock IRS. A nice turbo on that m103/m104 should have you in SN95 power range

And it's completely rust free and in excellent condition!  Just needs a couple things, the K1 spring installed (which I have) and some exhaust work and the a/c works but the blower motor just died.  And the passenger side window is stuck up, since that motor died.  But SWMBO hates the car so it's gotta go, so once I get a few pictures of it I'll be posting it for sale on here.  Probably a grand OBO.  I just need it gone.

5.0:

Pros - torquey, far superior aftermarket, easier to modify/work on

Cons - not as dependable at the limit, rev character isn't as free, block safety concerns (same goes for the T5)

4.6:

Pros - significantly more dependable, will take a beating all day (ask me how I know this :P), no problems revving to the limit nor being built to sustain 7K

Cons - NPI blocks are trash unless you get PI parts, in which case you're better off starting with a PI car in the first place (unless you plan on PNPing the PI parts anyways), more harder to work on and less aftermarket parts in addition to having far weaker mod effects

If you get an NPI car, I'd suggest throwing in the aluminum 2V PI-block from the 2002-2005 Explorer - more power potential AND less weight on the front end (or you can do this same thing to the Thunderbird of the 90s with SLA suspension up front)