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Make 503HP With A $350 Junkyard 302

How to Add 80 HP with a Simple Cam Swap

By , Photography by

Conclusions

In review, we rescued a used 5.0L Ford from the boneyard, ported the heads, added a cam, carburetor, intake manifold, and headers and pulled an amazing 376 hp out of the mix. The engine never huffed oil out of the breathers, and the spark plugs all looked excellent. In a 3,250-pound car like a Mustang with 3.50 gears and an automatic with a 2,800-rpm converter, this 5.0L could pull 12.80s at 108 mph. That's fantastic for the minimal investment we made. With nitrous, this is easily a mid-11-second ride. We've already been motivated to put this engine in a buddy's Mustang. Nudge us with emails and we'll make it happen.

Cam Specs

Camshaft Advertised Duration Duration at 0.050 Valve Lift Lobe Sep. Angle
Stock 256/266 190/200 (est.) 0.450 NA
Lunati – 711 272/280 221/229 0.549/0.565 112
Lunati – 712 282/290 231/239 0.571/0.565 112

By the Numbers

We started with a 120,000-mile 5.0L out of a Ford Explorer, removed the EFI and DIS and pocket ported the stock GT40P iron heads with stock valve sizes. We also added an Edelbrock Performer RPM dual-plane intake and a set of 15⁄8-inch headers with no mufflers. The HP DIFF column on the far right lists the horsepower difference between Test 1 and Test 3. The asterisk HP differences are calculated using Test 1's 294hp peak.

Test 1:750-cfm carburetor, dual-plane intake manifold, and stock camshaft.
Test 2:Changed to the smaller of the two Lunati camshafts—no other changes.
Test 3:Installed the larger Lunati cam—again, no other changes.

RPM TQ1 HP1 TQ2 HP2 TQ3 HP3 HP DIFF
3,000 319 182 321 183 311 177 -5
3,200 314 191 320 195 314 191 0
3,400 316 204 327 212 327 212 8
3,600 318 218 333 228 335 230 12
3,800 321 233 339 245 343 248 15
4,000 325 248 345 263 349 266 18
4,200 328 262 347 277 353 283 21
4,400 325 273 348 292 355 298 25
4,600 321 281 345 302 354 310 29
4,800 314 287 343 313 353 323 36
5,000 304 289 342 325 353 337 48
5,200 295 292 338 335 350 347 55
5,400 286 294 334 344 346 356 62
5,600 330 352 342 364 70*
5,800 320 354 336 371 77*
6,000 306 349 329 376 82*
6,400 314 371 77*

Parts List

Description PN Source Price
Used 5.0L Ford engine N-A Junkyard $350.00
Edelbrock Perf. RPM intake 7521 Summit Racing 289.97
Holley 750-cfm mech. sec. 0-4779 Swap Meet 250.00
Lunati camshaft, hyd. roller, small 20350711 Summit Racing 299.97
Lunati camshaft, hyd. roller, big 20350712 Summit Racing 299.97
Lunati rocker arms, 1.6:1 15385-16 Summit Racing 264.97
Lunati timing chain set 94251 Summit Racing 43.97
Lunati pushrod set 80745-16 Summit Racing 35.97
Lunati valvesprings, 1.450 dia. 73100-16 Summit Racing 129.97
Manley exhaust valves 10723-8 Summit Racing 132.97
Comp Cams 3⁄8 rocker stud 4515 Summit Racing 59.97
Comp Cams guide plates, flat 4816-8 Summit Racing 17.19
Comp Cams guide plates, adj. 4835-8 Summit Racing 54.97
Comp Cams composite gear 35200 Summit Racing 114.97
Comp Muscle car oil, qt 1594 Summit Racing 8.97 (ea)
Nitrous Supply Powerstar kit 03001 Nitrous Supply 603.75
ARP head bolts 154-3601 Summit Racing 49.86
ARP intake bolts 154-2001 Summit Racing 28.97
Fel-Pro head gasket, MLS 1133 Summit Racing 60.97 (ea.)
Fel-Pro head gasket, composition 10111 Summit Racing 29.97 (ea.)
Fel-Pro intake gasket, stock port 1250 Summit Racing 20.97
Fel-Pro valve cover gasket VS50029C Summit Racing 13.97
Fel-Pro timing cover gasket TCS45449 Summit Racing 12.97
Fel-Pro water pump gasket 35352 Summit Racing 1.97
MSD spark-plug wire kit, black 31183 Summit Racing 85.97
Autolite spark plugs (8) 764 Summit Racing 23.92
Autolite spark plugs, race (8) AR472 Summit Racing 39.76
Fram oil filter, ultra synthetic XG2 Summit Racing 8.97
Comp Cams 10W30 oil, 5 qts. 1594 Summit Racing 8.97 (ea.)
Labor
Labor to port cylinder heads NA Slover Porting 325.00
Machine for studs and guideplates NA Slover Porting 140.00
Machine spring pockets NA Slover Porting 65.00


Changing cams in the 5.0L was easy. Don't forget to install the limiter plate on the block before installing the cam gear. It's also critical to install the dog bones over the hydraulic roller lifters with the dot facing up. This will properly retain the lifters. If the dog bones are installed upside-down, this could cause massive cam damage if the lifters are allowed to spin. Don't make that mistake.

For the induction side of our test, we used an Edelbrock Performer RPM Air Gap dual-plane intake combined with a Holey 750-cfm mechanical secondary carburetor. Because this engine only made 375 hp, we might have made the same power with a smaller 650-cfm carb.

Dyno testing the 302 didn't require a significant amount of tuning. We rejetted the Holley 750 leaner by two jets sizes in the primary to stabilize the air/fuel ratio at around 12.5:1 throughout most of the pull. The tight combustion chamber only wanted 34 degrees of timing for best power. When we added timing, it lost power.

We used a set of colder Autolite race plugs with a non-projected nose for the nitrous. You can't see it in this photo because the evidence is very faint, but this plug revealed evidence of detonation with a few very small black specs on the porcelain. Detonation occurred even though we pulled 8 degrees of timing with the nitrous engaged. This means we were right on the edge. It's possible that pulling 10 degrees of timing might have made more power.

We used Nitrous Supply's entry-level Powerstar kit, which is adjustable from 50–250 hp. You can also easily upgrade this system by adding a larger nitrous solenoid since the fuel solenoid is capable of delivering fuel up to 400 hp. The plate is the same one used in larger kits.

SOURCES
Comp Cams
3406 Democrat Road
Memphis
TN  38118
800-999-0853
http://www.compcams.com
Manley Performance Products
1960 Swarthmore Avenue
Lakewood
NJ  08701
732-905-3366
http://www.manleyperformance.com
Lunati
662-892-1500
http://www.lunatipower.com/
Autolite
39 Old Ridgebury Road
Danbury
CT  06810
800-890-2075
http://www.autolite.com
Edelbrock
2700 California St
Torrance
CA  90503
310-781-2222
http://www.edelbrock.com
Federal-Mogul
26555 Northwestern Hwy.
Southfield
MI  48034
248-354-7700
http://www.federal-mogul.com
Nitrous Supply
15552 Producer Ln
Huntington Beach
CA  92649
714-373-1986
http://www.nitroussupply.com
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2 comments
80thill
80thill

I am wanting to use the smaller cam choice for this set up on my GT40p engine but worried about piston to vale clearance, did they do any thing special or will I be ok?  1988 stock short block gt40p heads

Pint_and_a_Shot
Pint_and_a_Shot

Did you guys try less timing?  Years back when I ran GT40Ps on a carb'd engine combination they wanted 29-31° for max power.  Power dropped beyond that.

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