85 vs. 86 vs. 87> engines

[MrKwik]

I have this all straight in my head but putting it to text I will probably manage to confuse poeple so bear with me.

In 85, the 5.0 is rated at 210hp & 270ft/lbs. 86 dropped to 200hp but got 285ft/lbs. Main differences being that ford used the chrappy high swirl heads in 86, but they also gave it a better true dual exhaust and fuel injection. So basically we lose 10hp but since ford changed more than one thing, how much of a loss were in the heads and how much was gained back by the ehxaust or vice versa? In 87 we go up to 225 and 300 respectively due to the E7 head change and slightly larger TB and intake plenum. Now haw much was due to the heads and how much did the intake account for, and would the power numbers in 87 be the same if ford had never went to the 86 head at all, hadn't destroyed the mold and were still using the 85 heads all the way up to 93?

I know thats probably hard to follow but basically what I am wondering is, what do you suppose it would be rated at if ford had retained the 85 heads, added the true dual exhaust and went to the 87 style intake and TB? Are the 85 heads much different from the E7 heads? Better? Worse?

 

[dcarlson]

The compression was also raised in 1986, so that is some of your torque gain.
Compression ratios:
1985 8.4:1 (I think)
1986 9.2:1
1987 9.0:1

I've heard that 1985 heads are basically the same as E7TE heads except they don't have the cutouts that let you remove the roller lifters while the heads are on. I haven't checked this myself.

 

[MrKwik]

The compression was also raised in 1986, so that is some of your torque gain.
Compression ratios:
1985 8.4:1 (I think)
1986 9.2:1
1987 9.0:1

I've heard that 1985 heads are basically the same as E7TE heads except they don't have the cutouts that let you remove the roller lifters while the heads are on. I haven't checked this myself.

Those are correct numbers as far as I know which also gets me wondering what the volume of the 85 chambers are compared to the E7's. The 85 motor Im overhauling has 4 relief flat top pistons while all the 87+ motors I have been through had dished pistons. Im guessing that the 85 heads have fairly large chambers?

 

[90mustangGT]

The 87+ motors are better all around. The 85-86's had Cast pistons I belive, while the 87+ had forged. 86 pistons have clearance issues with any aftermarket head. E5 heads are about as good as E7's but from what I have heard the E7's with the exaust "heat riser" bumps ground down are far better. 86 heads not only are restrictive, but the valves are shrowded, best viewed form inside a recycling bin. The 87+ intake with with the ported lower rivals the cobra intake.

 

[95GTAODE]

The '85 and '86 motors both had forged pistons, with the '86 getting true flattops with no reliefs. The E5 head is exactly the same as the D9 head used on '79-'84 5.0's, just with the reliefs built in to be able to remove roller lifters, which '85 was the first year the roller cam was used. Since the castings were modified, they received an updated p/n. The biggest advantage the E7's have compared to the E5 is a 60-63cc chamber compared to a 69-72cc chamber in the D9/E5 heads.

The redesigned for '87 upper intake was prolly worth 5-10hp over the '86 with the better ports and chambers in the E7's accounting for the rest.

IMHO, the ultimate factory parts combo would prolly be an '87 longblock with the '85-'86 cam, and the '85 carb and intake. Toss on GT40 heads and the 1.7 RR's to make the carbed Cobra vesion.

 

[MrKwik]

The 87+ motors are better all around. The 85-86's had Cast pistons I belive, while the 87+ had forged. 86 pistons have clearance issues with any aftermarket head. E5 heads are about as good as E7's but from what I have heard the E7's with the exaust "heat riser" bumps ground down are far better. 86 heads not only are restrictive, but the valves are shrowded, best viewed form inside a recycling bin. The 87+ intake with with the ported lower rivals the cobra intake.

Actually they were forged starting in 85. And I realize the 86 heads are crap. Im just basically wanting to know where we would be at if they never changed anyting in 86. What I am doing is trying to put the best combination together for my 86 only using what I already have on hand. Im tryng to figure out if will be on par with the 87+ cars or closer to the 86 or 85 power numbers.

The redesigned for '87 upper intake was prolly worth 5-10hp over the '86 with the better ports and chambers in the E7's accounting for the rest. IMHO, the ultimate factory parts combo would prolly be an '87 longblock with the '85-'86 cam, and the '85 carb and intake. Toss on GT40 heads and the 1.7 RR's to make the carbed Cobra vesion.

Is the 85-86 cam better than the 87+? I have both but I figured they were the same. If thats the case then I will be sure to use the 85 one. Basically what I think I will end up with is the 85 block & heads with an 89 intake/TB and maybe have TMoss do the lower if it will gain me anything with the 85 heads and cam. I cant afford new heads for this one and it needs to remain completely stock appearing down to the speed density. Doesnt need to be beast but I want it to be able to hold its own with aero nose cars.

 

[hrspwrjunkie]

The 87 is the same cam as the 85 and 86. The same cam was used from 85 through early 88.

 

[maverick0716]

Only the 5 speed versions of the 85 5.0 had the roller cam and forged pistons. The CFI units got the shaft big time, lol.

I am in the process of putting my new heads/cam in my 85. I took the engine out of the car to make it easier and to be able to clean up the engine. I can tell you the combustion chambers on the E5 heads are huge! Also the cam is the same as the other later year 5.0 cams (266 adv. duration/.444 lift).

One more thing, I was under the impression that the 87+ pistons were the same as the 85's? You know, flat tops with valve reliefs.

 

[Daggar]

85 pistons were dished.

 

[MrKwik]

85 pistons were dished.

Not mine. Flat as can be.

Only the 5 speed versions of the 85 5.0 had the roller cam and forged pistons. The CFI units got the shaft big time, lol.


One more thing, I was under the impression that the 87+ pistons were the same as the 85's? You know, flat tops with valve reliefs.

Mine came from an 85 5-speed with a carb, not the CFI auto. I have rebuilt 6 or 7 87-93 5.0 engines and all had dished pistons. I have boxes of stock forged dished pistons in my garage.

 

[Daggar]

Not mine. Flat as can be.

Then they're not 85 pistons.

 

[MrKwik]

what do you think I got here then? As far as I know it was the original motor in the car and the bottom end was stock and it is definately a roller motor because I tore it down. It had the stock heads but they had recently been rebuilt. All the bottom is standard size/standard bore. All the bearings and pistons have ford ovals and part numbers on them. What other roller block would have had flat tops?

 

[dcarlson]

87-92 forged piston are dished too, but the dish is REALLY small, and there are 4 valve reliefs.

 

[Daggar]

Those look like 87+ pistons to me. Have you checked the bore yet?

 

[MrKwik]

Those look like 87+ pistons to me. Have you checked the bore yet?

All the 87+ motors I have torn down have dished pistons, I have most of them in a box in my garage. The ones in this motor are totally flat except for the reliefs obviously. Which also rules them out as being 86 because they do have valve reliefs. Its stock bore, factory ford pistons no undersize anything.

 

[maverick0716]

Then they're not 85 pistons.

Mine are flat as well

 

[74ProII]

If it wasn't a roller...identical to 83-84 pistons.

 

[Daggar]

Let's ensure that we all have the same definition of terms here:

DISHED PISTON:

DOMED PISTON:

FLAT TOP PISTON:

FLAT TOP PISTON WITH VALVE RELIEF:

Most of these examples are extreme examples. There are widely varying degrees of each. The 85 H.O. (unless someone has gone back in time and changed everything) used a dished piston and had a compression of around eight and a half to one. The 86 used flatops and had a compression of a bit over nine to one. The 87+ Forged pistons were flat top pistons with valve reliefs and hovered around nine to one compression. I'm not sure where all the confusion is coming from.

 

[maverick0716]

Let's ensure that we all have the same definition of terms here.......Most of these examples are extreme examples. There are widely varying degrees of each. The 85 H.O. (unless someone has gone back in time and changed everything) used a dished piston and had a compression of around eight and a half to one. The 86 used flatops and had a compression of a bit over nine to one. The 87+ Forged pistons were flat top pistons with valve reliefs and hovered around nine to one compression. I'm not sure where all the confusion is coming from.

No, my 85 GT 5 speed (first year of the roller cam and forged pistons) came with flat top pistons with valve reliefs. The reason for the super low compression was not because of the pistons. The E5 heads had a 69-70 cc combustion chamber....that's about 8-10 cc's bigger than the E7 heads.

 

[Daggar]

Well... I can't speak for ALL 85's (that's for sure), because I've only ever torn one apart. THAT one... had dished pistons with valve reliefs (not nearly as severe as the one pictured). Maybe they did some split year funkyness or something.

Check this out too:
http://www.mustanggt.org/gtchange.htm
Edit: Look at the engine comments for 85 and 86.


As for the original poster.... If they're forged castings... use em!!! You can shave the heads or do any number of other things to put the cmopression where you want it. The picture you provided looks like it's showing some healthy slugs.