gt40 gtp40 help me decide and run down the parts list for 87 GM

[bigblackmariah]

after two summers of high prices and low choices i have finally come across three 5.0 explorers in the same yard. there is a 99 which i heard run breifly last year before it was pulled for an engine swap that fell through, so it's been sitting out all winter on the ground. the other two are "can hear run" although i havent. on the ground 99 motor, i cant find anything to denote a gtp from a gt head. i have been wanting to do this for two years, the planets are aligning and now im getting cold feet. i dont want to buy the wrong engine (lower factory output). im also a little fuzzy on the computers. only mustang? not 5.0 cougar or t bird? and not the explorer?. please help me by responding quickly, i feel the best part of this deal slipping through my hands.

without my notes here's what i think i understand about doing a MAF HO swap

cam with HO profile
HO intake (will the explorer work?)
gt or gtp heads
mustang computer (no other 5.0 choices?)
mustang shorty headers
intake/MAF plumbing
MAF sensor (will the explorer one work?)

now... buy the pig in a poke "floor model" or buy one of the '96's that i can hear run today? i have the know how to do the head/intake swap, or would i want to gamble on the '96's and just do an engine swap? any guidance from someone who can get me out of this pre-buyer's remorse would be appreciated.
BTW there is/was a nice twpo door 79-maybe 82 choc brown i say was because they had to drive it around the yard and scruff it up a bit, said it had a hole in the gas tank. any two door guys need anything, let me know.
the yard is billie joe's in peoria IL

[BerniniCaCO3]

Hi!

I'm going through this right now.
GT40s were only on '96 and some '97 explorers (earlier in the year: I've no idea on the cutoff).
I can check my own heads to see if it was in front or in back, and I'll take a photo if it'll help: but on one of the ends of the head you'll see 4 hash marks, just cast lines going up and down. This is on the very end, either where some of the accessory brackets bolt on or possibly in back where it faces the driver. You should be able to see it more easily on that engine that's already out on the ground.

1999 is gt40p; it'll have 4 hash marks. If it's gt40 it'll be 3 hash marks. The gt40 heads also say F3ZE on the inside, but you will have to go through the trouble of pulling them first before you'd see that! Which is why I suggest the marks.
Again, I can take a photo... if there's a 97 there that might be in doubt.

Definitely not the explorer computer. Our systems are obd-i, explorer is obd-ii. It can and has been done, and I know there's someone on this forum who has done it: but I don't want that hassle, and you probably don't either. Lots of rewiring, and furthermore, we have mechanical tv cables: explorers had if you will tranny shift-by-wire, and the computer will experience phantom limb syndrome because it wants to see a transmission to control!

OH: the other 2 are '96s? The 5.0/302/v8, right, not the inline 6 explorer? Get those! Gt40 heads will work with your exhaust manifold. Get one whole engine, and then get the 2nd set of gt40 heads (if it's 96, they're gt40): there's someone else on this forum who's been looking for them.
Around here in Baltimore, they go QUICK and I'd be in the yard tomorrow morning to pull them. The sell for $250 on craigslist.

[BerniniCaCO3]

OK, now for the electrical work and the exhaust.
There are lots of combos and someone else might know if there's some leeway, but as a rule you really want to match the MAF to the computer, from the same car, or if bought apart on ebay, with codes that indicate they matched.
Again, can't use the explorer computer, so you really shouldn't use the explorer maf.
The computer has to match the engine, so anything that has a 5.0/302 will work. I've found lots of the smaller-engined mustangs in the yard near me, no 5.0s yet. The 5.0 mustang with the maf you want would have been at least '91 and '92, I don't know if they had the 5.0s through '95? 1990 and earlier was still speed density, but, that might still work for you. I'm going to give it a try anyway for my own build, until I find a maf.

There were also later model lincoln mark vii's with the maf sensor, and earlier models still had workable speed density computers. You can check years on the door, or, just look under the hood and see if there's a mass airflow there past the intake!
If you do find a 2nd set of maf/computer from a 5.0 mustang or mark vii, let me know, I'd be interested.

As for exhaust, what is your budget? I just ordered everything and spent, gosh, $450 on everything: headers to tips and everything in between. That's being fairly frugal; got used mac headers and a used catted H-pipe. New mufflers, clamps, tailpipes and midpipes and tips added up to $320 shipped.
There are a couple threads I've been hanging out on prescribing a working formula of parts that'll do; the stock mustang exhaust doesn't work well past the H-pipe, and the stock mustang headers won't bolt up to the rest of your stock exhaust.
If you can get a '96 explorer v8 engine, your exhaust will bolt right up to it if you don't have the budget for the full dual exhaust swap right now. Goodness knows i didn't anticipate being quite $450, but it was, at the end of the day.

About camshafts.
I've got an HO cam in excellent shape, 60k miles on it, I'd sell for $30 shipped if you want it.
But actually, myself? I'm going with the explorer cam.
I've got a wagon with the 3.55 rear diff gear ratio. I calculated that passing someone in 3rd gear, kicked down from overdrive, at 75/80mph revs my engine to 3600rpm.
That's as hard as I ever accelerate.
And 90% of the time I'm cruising at 1800-2000rpm.
So I want low end torque.
They're not that different actually: http://www.grandmarq.net/vb/showthre...-Torque-Curves
Others have told me that the HO cam only "wakes up" at 2500rpm. It has a little more lift and overlap than the explorer cam. The HO cam should be more fun if you like to drive hard, and it's absolutely requisite if you do want to take your engine to 5000rpm on the racetrack; explorer cam is better for 2000rpm cruising.

So based on that I'm putting in an explorer camshaft, it'll be better for my daily driving purposes. If you've got an explorer engine, in good shape, you could just leave it be-- how will you be driving it?

Now a final bit of advice; how an engine runs does not tell you the full story. I'd look at mileage: If it's 200,000 miles, it's worn out and you'll want to do some overhauling. It could still sound smooth when they start it up for you, but after you swap it into your car and live with it for a month you'll notice that it's burning oil and not getting quite the fuel economy you were expecting, as all the tolerances will be loose.
I'd also at least pop off the valve covers and make sure there isn't black sludge indicative of irregular oil changes; that means extra wear all around for the mileage, and probably tearing down the engine and at least hot tanking everything before reassembling with fresh rings and gaskets would be in order. But not a bad idea no matter what. I'd probably rather have a 100,000 mile engine with a little sludge than a 200,000 mile engine that was cleaner; the first will likely still be more salvageable with some TLC, the second might need machining to get it back to spec: and that is Expensive. Of course, with very irregular oil changes it could be sludged to the point of locking up, or there could be serious scarring on the crankshaft and cylinder walls-- not saying that sludge is good! Just that a lower mileage with a little black oil could trump very high mileage even if it was impeccably maintained.

[BerniniCaCO3]

Final thing:
The harmonic balancer, and, I think, the flexplate also; are different for the HO than the stock lopo I'm assuming you have. They're the same for the explorer; for all intents and purposes it is the HO.
I'd get them too. Probably easiest just to buy the whole explorer motor whether you swap in an HO cam or not
The firing order is different on the HO/explorer than for our stock e6se engines, so just pay attention when you arrange the plugs on the distributor. It's 1-3-7-2-6-5-4-8
I think the distributors themselves are the same; if the '96 explorer has coil packs and no distributor, I think you can still swap yours into it, the casting bore is still there.

Oh, and, we have I think central fuel injection? Or batch fuel injection? Mustangs are sequential fuel injection, so there might be some minor kludge to execute there. I'm going to find out on monday when I do my own swap

[gadget73]

99 is gt40p. Look at the back corners of the heads, right at the edges of the valve cover. I think its the lower edge, closer to the exhaust ports. One corner will say GTP. Theres also a 4 bar casting mark on the front edge of the heads.

The Explorer cam works, or you can put an HO cam in. HO cam gives you a little more max RPM capability. Explorer cam is stronger under 2500 rpm, but dead by 4500.

Mark VII have a speed-density HO computer that may or may not work well with that motor. SOme people have had good luck with it, others have not. Mass air Mustang stuff from 89-93 has been pretty solidly proven to work well. It requires a little bit of harness modification but nothing serious.

If you're using Mustang MAF stuff, then the Exploder MAF doesn't work. I'm using a 90s Grand Marquis MAF housing with I think a 94 Thunderbird sensor inside it. Yes I know you're not supposed to do that stuff, but it works for me. The Grand Marq stuff ran great until I put an air filter in, then it ran like shit. Switching to the Tbird electronics made it run fine again.

[1987cp]

What are your goals for the car, inspection and emissions limitations, etc.? Absolutely nothing wrong with dropping in an Explorer motor with EEC-IV conversion, but it's good not to expect it to be a magic combination either. I thought myself extremely clever in '06 making sure I had a set of GT40 heads on one of my engines, only to realize more recently that they're not nearly as special or as hot-performing (or even as cost-effective) as I thought they were.

[bigblackmariah]

ok here's today's info:
ground model is a gt40 head set
popped the valve cover, gtp40 is cast in the head
im not worried about electrics too much because i plan to reprogram my PCM
EEC V computer from an explorer?
the trans is another issue i'd love to clear up
i have a nice aod from a 89 supercoupe, anyone know if i can use that?
could i also use the throttle body and MAF from the coupe?
the TV cable i intended to keep but just keep a constant value for the trans inputs on the tables, which i think would cure codes. does this sound right? all the rest of the tables would have to be reworked too. this car is not really my daily driver. what i'm looking for is a sinister sleeper. using my original block, the p headers and 2 1/4 duals, what would i hope to be gaining?
my progress is slow due to all sorts of factors but so far this is how it is shaping up (nothing since last summer)

poly rear bushings HD shocks
245/60/15 on turbines
2 1/4 dual exhaust
new water pump, TV cable

planned upgrades
summer 11

gtp heads,intake (explorer? HO?), headers, cats, cam, laptop tune
replace front shocks/bushings
respray
swap t bird diff gearing

what i want is about 75 more hp hooked up to my t bird gearing 3:08 i think, with the fresh t bird trans gearing. quick but not a crazy winder.

i dont know if i can wait on the engine, i may pick it up friday noon.
thanks for all the help so far. anyone with the EEC V or discouragement please let me know.

[1987cp]

Final thing:
The harmonic balancer, and, I think, the flexplate also; are different for the HO than the stock lopo I'm assuming you have.

Whatever are you talking about? ALL "late" 302 engines (post-1981, I think) use the one-piece rear main seal and 50-oz. imbalance. All of them. Prior to that, all 302s used the same 28-oz. imbalance as 351s and two-piece rear main seals. So please don't go spreading misinformation about their people's '87 engines.

Also, how could you possibly confuse CFI with any sort of port fuel injection? CFI looks like a carburetor with fuel injectors mounted on top. Uses the big round carb-style air cleaner, too. Port injected 5.0s have the stupid snakey intake, throttle body out to one side pointing sideways, and eight fuel injectors, and had the annoying air cleaner box mounted to the d/s exhaust manifold. 5.0L Panthers from 1986 on received port fuel injection. 5.0L Panthers from '82 or '83 (earlier for Lincolns) to '85 received CFI, as did automatic 5.0 Mustangs from I think '83 to '85.

Also, ALL port-injected car 5.0s (both HO and lowpo) I'm aware of were sequentally injected, or SEFI. That means each injector fires individually. From what I've read, typical port-injected 5.0 trucks were batch-fire, which means multiple injectors fire at once. One interesting thing about batch-fire is that it apparently doesn't care whether you use a 302 or 351/HO firing order.

[gadget73]

the Explorer balancer is different. Its shorter and has a crank position tonering attatched to it. It will not work with stock accessories. yes its the right imbalance, but it just don't work.

flexplate is the same 82+ on a 302. 351's got different stuff.

The Explorer ECM will only work if you convert to OBD2, and honestly the Explorer ECM is probably not optimal for that. You probably would want to find a 5.0 F series truck or E series van with a manual trans if you want to keep the AOD. If you're cool with an electronic 4R70w (and honestly this is a good idea), then the Explorer stuff can work. I don't know that an obd2 swap has ever been done on one of these cars, so you'd be sort of on your own there. I know its been done to other vehicles so the info is out there. The increased tunability and diagnostics available with obd2 aren't a bad thing at all. The kink is the accessories. I can tell you from personal experience that fitting Explorer accessories to a box is a total PITA. You'd need to come up with some other way to drive the crank sensor. I suspect an Explorer balancer with a suitable spacer to put the stock crank pulley where it needs to be is the path of least resistance.

[1987cp]

Weird-looking little things, those Explorer balancers. I probably still have mine somewhere, though I can't think why.

[sly]

paperweight

same reason I still have the original planetary gears from my AOD. Really freaking large paperweight.

that... and proof of gearhead status. You have to have some random parts that will never get used again.

[1987cp]

:lol: You're probably right, though! I did think it was the weirdest thing ever to see a balancer with the crank position sensor teeth AND the integrated pulley arrangement.


But of course, the upshot is that the Exploder balancer can be replaced with any 50-oz. SBF balancer when preparing for the EEC-IV or carbruletor conversion and used with your stock Vic pulley system, which is really a pretty decent one except for the alternator and A/C compressor being located somewhat inconveniently.

[Forcus]

the yard is billie joe's in peoria IL

Interesting, I live about 40 mi N of Peoria and work in peoria.

[86VickyLX]

The kink is the accessories. I can tell you from personal experience that fitting Explorer accessories to a box is a total PITA. You'd need to come up with some other way to drive the crank sensor. I suspect an Explorer balancer with a suitable spacer to put the stock crank pulley where it needs to be is the path of least resistance.

I just noticed that this was a few months ago. Anywho, for those of you who do not know, the magic balancer exists. It just has to be made. Thain linked me to a thread in another site about this particular issue being addressed. It's not cheap, but it'll work. it's kind of tempting actually.

[86VickyLX]

P heads need specific headers to work right. Or need exhaust modifications to access spark plugs. They are a better design than the GT40 heads, even if the valves are smaller.