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Text and Photos by Mark Houlahan
When it comes to budget upgrades, the first items that often come to mind are underdrive Pulleys Rightfully so, we believe. These little power-making gems have been around for more than a decade. Whether you bolt them to a stone-stock 5.0 or a blown 347 they still make power. With prices less than $200 (some sets are priced less than $100), a pulley upgrade is a nice budget modification that will make power and can usually be used alongside future upgrades with no problems. The one exception would be having to install supercharger crank pulleys in place of underdrive crank pulleys for the installation of a supercharger.
The typical underdrive pulley kit for 5.0s is a three-piece kit that replaces the crankshaft, the water pump. and the alternator pulleys with either steel or aluminum pieces sized appropriately to slow down these belt-driven accessories. We contacted March Performance to discuss our project, as we wanted a budget-friendly product that would be easy to install and yet be durable and long lasting.
Knowing the pulleys would go on at friend's street 5.0 that is driven every day we also wanted to have plenty of charging power and coolant flow for stop-and-go traffic. Dan Garn of March Performance suggested the company’s tried-and-true best seller PN1015. This is a three piece powdercoated steel set from March Power & Amp Series with a 4,375-inch crank pulley, and a 2-inch alternator pulley, Dan guaranteed this set would make power and there’d be no problem in daily driving. For installation we visited LaMotta Performance in Longwood, Florida, so we could dyno test the effectiveness of the pulleys kit. Now grab your tools and let's head to the garage.
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| 1. Since LaMotta tech Jay Meagher was I busy installing 6x9 speakers the day we arrived, Jake LaMotta mugged for our digital camera and installed our pulley set. It took him only a few seconds to remove the fan and fan shroud as an assembly. The water pump pulley came off easily as well. |  |
2. Four hex-head bolts retain the original crankshaft pulley. Remove the bolts and then give the crankshaft pulley a few taps (if it's stuck) to unseat the pulley from the lip of the crankshaft damper. |
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| 3. The last stock pulley to remove is the alternator pulley The use of an air gun will be required to zip this baby off If you have access to air tools, then by all means, remove it yourself If not, the alternator is easily removed from its bracket (only two bolts and a wiring connection) and can be brought to a shop or auto parts store where they'll gladly swap the pulley for a few bucks |  |
| 4. The new crankshaft pulley from March measures 4.375 inches in diameter and is retained by Allen-head bolts due to its smaller diameter The pulley is aligned to the crankshaft damper as was the stock pulley |  |
| 5. Jake seats the new crankshaft pulley to the damper and then starts all four Allen-head bolts before tightening them down Make sure the pulley is seated correctly on the damper as you tighten the bolts so the pulley doesn't shift and wobble when the engine is running |  |
| 6. Shown here, the water-pump pulley measures 5.5 inches and features a smooth outer belt path similar to the newer modular-engine-family pulleys After extensive testing. March has determined that belt-centering lips are no longer required When sized correctly, the belt will stay on with no problems |  |
| 7. At this time, all Jake does for the water-pump pulley is seat it to the water-pump driveshaft and align the bolt holes for installation of the fan later. He installs one bolt loosely at this time to prevent misalignment and to hold the pulley in place. |  |
| 8. The alternator pulley in the March Power & Amp set is a miniscule 2 inches. Jake told us we shouldn't see any charging problems with a pulley of this size, but we might need a shorter serpentine belt. |  |
| 9. The new alternator pulley comes with a split washer to secure the pulley with the OE retaining nut. |  |
| 10. Use the air gun to install the new pulley to the alternator Due to the pulleys inside diameter, you may need to switch to a thinner socket, though the impact swivel that Jake used worked fine for removal and installation. |  |
| 11. Slide the stock fan assembly and fan shroud parts back into place. With the fan-mounting hub (actually the fan clutch) close to the water pump, carefully remove the single bolt holding the pulley in alignment. Place the fan onto the water' pump hub, securing everything with the four OE bolts. |  |
| 12. Reinstall the two 7/16-inch fan-shroud bolts (make sure the shroud is seated in the bottom of the radiator) to secure the shroud. Complete the installation by reconnecting the coolant overflow hose to the radiator |  |
| 13. After slipping the stock belt back on. we found the stock belt was a hair too long. Jake set us up with a 1/2-inch shorter belt and we were in business. |  |
| 14. With the March pulleys in place and fresh serpentine belt hung around them, we're ready to spin the rollers on LaMotta's Dynojet |  |
| 15. After some warm-up time. Jake put the '89 notch through its paces. Since this dyno is outdoors, we had to dance around a little bit of rain to get the installation and dyno work done, but it was worth it. Can you say 15 hp? Take a look at the dyno results, but this 5.0 picked up solid power completely across the board. |  |
| 16. Though the worn-out stock valve-springs meant it wasn't worth pushing the 5 0 above 5000 rpm, it was scary to see the speedometer peg on each dyno run as this car had the original 10-hole wheels with only 205/50R 15s, which have an overall height of just 23 inches -3.6 inches shorter than the OE tire. 5.0 |  |
| On
the Dyno Testing underdrlve pulleys might sound trivial, but it's one of those subjects that generates the most questions for us. Do they really make power? Will I have charging problems? As we've said many times before - yes, underdrive pulleys make power. How much? More on a stock car such as the one featured here, but you'll see an improvement even if your car has heads/cam/intake or other such goodies. Takes look and compare the numbers.This 153,000-mile 5.0 picked up solid horsepower and torque all the way from start to finish on the dyno. You can't ask for more than that. Fifteen horsepower for less than 100 bucks-why didn't I think of selling these things! |
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| RPM | STOCK TORQUE |
STOCK POWER |
W/ PULLEY TORQUE |
W/ PULLEY POWER |
| 2.350 | 258.8 | 115.8 | 263,0 | 117.7 |
| 2.400 | 259.6 | 118.6 | 265.2 | 121.2 |
| 2.450 | 260.9 | 121.7 | 266.4 | 124.3 |
| 2.500 | 261.5 | 124.5 | 26.8.0 | 127.6 |
| 2,550 | 262.3 | 1274 | 269.2 | 130.7 |
| 2.600 | 262.9 | 130.2 | 270.3 | 133.8 |
| 2,650 | 263.8 | 133.1 | 271.2 | 136.8 |
| 2,700 | 266.0 | 136.8 | 274.2 | 141.0 |
| 2.750 | 267.4 | 1400 | 276.6 | 144.8 |
| 2.800 | 268.2 | 143.0 | 278.8 | 148.6 |
| 2,850 | 270.2 | 146.6 | 280.4 | 152.2 |
| 2.900 | 272.1 | 1502 | 283.0 | 1563 |
| 2,950 | 274.2 | 1540 | 284.7 | 159.9 |
| 3,000 | 274.7 | 156.9 | 285.2 | 162.9 |
| 3,050 | 274.4 | 159.4 | 284.7 | 165.3 |
| 3,100 | 274.3 | 161.9 | 286.4 | 169.1 |
| 3,150 | 274.9 | 164.8 | 287.2 | 172.3 |
| 3,200 | 275.9 | 168.1 | 286.3 | 174.4 |
| 3.250 | 275.6 | 170.5 | 286.4 | 177.2 |
| 3,300 | 274.9 | 172.7 | 286.2 | 179.8 |
| 3,350 | 274.4 | 175.0 | 286.8 | 182.9 |
| 3,400 | 275.4 | 178.3 | 2874 | 186.0 |
| 3.450 | 275.9 | 181.2 | 287.9 | 189.1 |
| 3,500 | 274.8 | 183.1 | 287.3 | 191.5 |
| 3.550 | 273.8 | 185.1 | 287.2 | 194.2 |
| 3.600 | 273.3 | 187.3 | 286.8 | 196.6 |
| 3.650 | 272.0 | 189.0 | 285.7 | 1985 |
| 3,700 | 270.1 | 190.3 | 284.9 | 2007 |
| 3.750 | 268.9 | 192.0 | 284.7 | 203.3 |
| 3.800 | 267.8 | 193.8 | 281.7 | 203.8 |
| 3,850 | 265.8 | 194.8 | 281.9 | 206.7 |
| 3.900 | 263.7 | 195.8 | 279.9 | 207.8 |
| 3.950 | 258.0 | 194.0 | 277.6 | 208.7 |
| 4.000 | 259.2 | 1974 | 275.5 | 209.8 |
| 4,050 | 258.6 | 199.4 | 274.2 | 211.4 |
| 4,100 | 255.2 | 199.2 | 271.5 | 211.9 |
| 4,150 | 254.7 | 201.3 | 269.0 | 212.6 |
| 4.200 | 246.1 | 196.8 | 266.8 | 213.4 |
| 4,250 | 247.7 | 200.4 | 264.0 | 213.6 |
| 4.300 | 245.2 | 200.8 | 262.7 | 215.1 |
| 4,350 | 244.3 | 202.3 | 259.8 | 215.1 |
| 4,400 | 240.1 | 201.2 | 256.3 | 214.7 |
| 4,450 | 237.6 | 201.3 | 254.2 | 215.3 |
| 4.500 | 236.0 | 202.2 | 252.7 | 216.5 |
| 4.550 | 234.8 | 203.4 | 249.7 | 216.3 |
| 4,600 | 230.5 | 201.9 | 246.9 | 216.3 |
| 4.650 | 228.9 | 202.7 | 245.0 | 216.9 |
| 4,700 | 226.2 | 202.4 | 242.7 | 217.2 |
| 4.750 | 223.4 | 202.1 | 241.2 | 218.2 |
| 4,800 | 219.9 | 201.0 | 238.7 | 218.1 |
| 4.850 | 218.0 | 201.4 | 235.7 | 217.6 |
| 4,900 | 214.3 | 199.9 | 232.6 | 217.0 |
| 4,950 | 212.3 | 200.1 | 229.7 | 216.5 |
| 5,000 | 208.9 | 198.9 | 226.8 | 215.9 |
| SOURCES LaMotta Performance Dept. 5.0 Longwood, FL 32750 407-695-45-49 |
| MARCH PERFORMANCE, INC. - 16160 PERFORMANCE WAY - NAPLES, FL 34110 TEL: (239) 593-4074 - FAX: (239) 593-4564 - EMAIL: info@marchperfinfo.com |