5.0 engine thoughts

[Scott Peters]

Hypothetical question for you guys and gals.
It’s about our 4 eyed 302’s.
Please correct me on anything that I got wrong.
This is all based on stock cams and heads for their respective years.

1982 5.0 GT/ LX were rated at 157HP.
The 83-84’s were rated 175HP.
Was the 20HP increase just do to the addition of a Holley 4barrel ?

Take the 85 GT with 4 barrel, it’s rated at 210HP.
Is this because of the roller cam and headers that still dumped into one cat and then spit into duals?

The 86 was FI and rated at 200…? I know that was a strange year with the E6 heads and all.
that had a true header/dual cat back system.

The the 87-91 FI with 225HP with the E7 head, later rated 215HP in 92-95.

I don’t think FI adds to the total HP number… but “ maybe “ ?

So if you added the 86-93 factory headers and cats with a free flowing cat back keeping all things the same,
What do you thing a 83/84 302 would be rated at ?

Has anyone put their basically stock 5.0 on a chassis Dyno ?

Thank God springs coming… got to get my Stangs out of the Barn.

Scott

[wraithracing]

The 1982-84 5.0 carbureted engines used the same camshaft. Which was supposedly a Ford Racing Marine camshaft. Specs were according to some:

Intake: 260* duration .416" lift, opens 15* BTDC, closes 65* ABDC


Exhaust: 274* duration, .444" lift, opens 68* BBDC, closes 26* ATDC


41* overlap


115* lobe center on intake, 114* lobe center on exh.

The 85-93 cam specs were the same as here:

Lift-Int: .444 in Exh: .444 in
Duration-Int: 266 Exh: 266
LSA- 115°

The 83/84 engines benefited from the 4 barrel carburetor and 4 barrel intake so that is the reason for the horsepower increase.

The 1986 had the craptastic E6 heads from the Thunderbird The "Swirl" heads.

The 1987 Mustang 5.0's received the E7TZ heads from the trucks that helped to bump HP back up.

The HP rating drop in 1992 was due to Ford actually using numbers with accessories, etc. installed and not just a bare engine as before due to SAE changes.

[Scott Peters]

Thanks for your input Trey.
I wish I understood more about the differences in cam spec’s.
I am not an engine builder… more of a rebuilder who relies on the
Old school “ if worked on a factory High performance engine “, then it should work on mine.
Like the Chevy “151” or Pontiac “068” …

So I gather that the roller cam , which is similar,and E7 heads along with the factory headers
Was the main difference for the 225 HP ?

So were the heads on the 85 different from the 82-84 to get 35 hp increase, or was it all in the cam ?
Scott

[wraithracing]

Thanks for your input Trey.
I wish I understood more about the differences in cam spec’s.
I am not an engine builder… more of a rebuilder who relies on the
Old school “ if worked on a factory High performance engine “, then it should work on mine.
Like the Chevy “151” or Pontiac “068” …

So I gather that the roller cam , which is similar,and E7 heads along with the factory headers
Was the main difference for the 225 HP ?

So were the heads on the 85 different from the 82-84 to get 35 hp increase, or was it all in the cam ?
Scott

I believe the heads were the same in 1985 and the camshaft along with the exhaust was the biggest reason for the power increase.

There are plenty of Ford Racing Alphabet camshafts that will give you a bit more than the original 82-84 if you want the added power, but still mostly stock engine. Just remember an internal combustion engine is nothing more than an air pump. Making changes so that it can pump more air per revolution is what increases the HP number. So a bigger camshaft that holds the valves open longer, more compression, larger intakes, etc. that all allow more air to be pumped is what drives those numbers up. Obviously the combination needs to be optimized when possible and all the parts need to work together. Just throwing a single plane 4 barrel intake on a stock engine is not going to make it perform better.

The later model EFI combo was a good setup and with a few mods can be a bit more powerful, but still drive like a stock engine. I have used several roller engines in my Four Eyes over the years and most have been converted to carburetor for cost savings or just ease of install. Unfortunately without a roller block retrofitting a roller cam can get expensive quick. So staying with a quality flat tappet camshaft is probably your less expensive option. There are several Comp Cams/Crane Cams flat tappet camshafts that are similar in specs to the 5.0 SEFI roller that you can use that will get you into the 225-250 HP range with just a 4bbl intake, carb, and good exhaust. Good Luck!

[bwguardian]

There is piston design which plays into the factor. The 82-84 pistons were cast with four valve reliefs on a flat top design. The 85 was basically the same design, but forged with a ring redesign. The 86 was the same as the 85 without the valve reliefs. The 87 brought back the valve reliefs, but with a center dish recess, which is about 4cc's of volume.

The heads were the same from 82-84. The 85 head was an early design of the 87 head, but still had big combustion chambers. The 86 head had smaller combustion chambers with the "swirl" design. The 87 heads were the 85 design with smaller combustion chambers.

For the 82-84 design, the added 4 barrel carburetor in 83 is what accounts for the difference in horsepower. The 85 increase in power would be from mainly the roller camshaft. When fuel injection came about in 86 I seem to remember the torque went up a little though the horsepower dropped.