Video: Stock 4.8L Short Block Pushes ’71 Datsun Into The 8s
It’s easy to overlook the “tiny” 4.8L truck mills. Thanks to a short stroke crankshaft and a bore on the small side they displace a paltry 294 cubic inches, and are only rated at somewhere around 270 horsepower in factory trim. Admittedly, those aren’t the most inspiring stats. It’s little surprise that most LS junkyard hunters will quickly pass up the 4.8L for the 5.3L, or even bigger 6.0L.
However, the video above will no doubt go a long way in upping the reputation of the smallest member of the LS engine family. Watch it and what you’ll see is Craig Poust’s 1971 Datsun being hurled down the drag strip by a boosted stock bottomed 4.8L in just 8.85 seconds at over 152 miles per hour.
The “Rusty Ranger”
“The shortblock has 180,000 miles, and must’ve come out of a park ranger truck from somewhere up north,” Poust tells us. “It was covered I more rust than I had ever seen before. I think I dropped a few pounds off the front just from knocking off all the rust scale.”
Unfortunately, the 4.8L wasn’t just rusty on the outside. When Poust pulled the heads he found a decent bit of surface rust on the cylinder walls along with oil gas that had transformed to a super glue like concoction. After pulling apart the short block, Poust sanded down the rust and removed the gunk before simply re-ringing the stock flat-top pistons.
Most of the time, the engine still thinks it’s in a truck…until it hits boost. -Craig Poust
The Engine Combo
Poust bolted everything back together, stabbed in a stock LS6 cam, and topped the engine off with a set of Texas Speed’s ported and polished 5.3L truck heads, LS9 head gaskets and ARP studs. From there, a custom turbo manifold system from 417 Motorsports spins a single 74mm turbo from PureTurbos.com. The boost is managed by a Turbonetics wastegate, and gets pushed through a 4-inch core front mount intercooler on its way to the FAST intake manifold.
For fuel, the 4.8L feeds off of 80-pound per hour injectors and two Walbro 255 in-line fuel pumps, with pressure control from an Aeromotive 1:1 FPR. A stock truck ECU converted to speed density acts as the brains of the operation. Poust is quick to give credit to a gent named Steve Williams from TunedByFrost.com for tuning the combo and really bringing out the power while maintaining reliability.
When it’s all said and done, the stock-bottomed 4.8L makes right at 700 rear wheel horsepower and 654 pound feet of torque on 21 PSI. Ironically, Poust has had several other arguably nicer LS mills in the Datusn, including a 500 RWHP LS1 and a 600 RWHP LS6. Both set ups pushed the Datsun into the low 10s and high 9s with a 6-speed transmission, but it was just too inconsistent for bracket racing. It didn’t help that banging through the gears was especially hard on the Datsun’s stock IRS and differentials.
Harnessing The Power and Keeping It Streetable
Looking for more consistency, Poust made the switch to a built 200-R4 auto trans from CK Performance when he swapped in the 4.8L. The IRS was ditched and replaced it with a 4-link suspension and a Ford 8.8”/9″ Frankenstein rear end of his own design since Poust had grown tired of replacing stock Datsun diffs every two runs. The frame of the tiny uni-body was also reinforced from front to back with 2 x 2 sections of steel channeled into the floorboards. For rolling stock the Datsun wears 15” Welds up front, and 15 x 10s were fit in the micro-tubbed rear of the car wrapped in 275/60/15 Mickey Thompson ET Street drag radials.
I could drive the car to California and back, run 8s at every track along the way, and still pull down 28 miles per gallon.
As evidenced by the video of the Datsun’s 8.85 second blast, the car dead hooks and even produces a nice little wheelie. Even so, Poust is adamant that the 2,900 pound Datsun isn’t a race car or even a sleeper – it’s simply a very, very fast street car. The Datsun still has its full interior, complete with leather seats from an Acura and a set of subs that Poust leaves in place even at the drag strip. The car does have a 4-point cage, but Poust is avoiding upgrading to an 8-second certified cage to keep the comfort of the car where it is.
“Most of the time, the engine still thinks it’s in a truck – until it hits boost,” says Poust. “I could drive the car to California and back, run 8s at every track along the way, and still pull down 28 miles per gallon.”
The Final Gear…
There are a lot of trigger words that will always catch the attention of gearheads; quickest, fastest, most powerful. Those words can be thrown around a lot, but we’re thinking it’s safe to go ahead and call Poust’s Datsun the “Quickest Stock Bottomed 4.8L Car in the World.” For more videos of the Datsun, including dyno pulls and drag strip passes with its other LS comobs, check out Poust’s YouTube Channel!