In the Words of Freiburger…

Hot Rod - - Contents - hHOTROD. COM/ David-Freiburger

We made 1,543 hp at 29.5 pounds of boost with a stock, junk­yard-fresh, LY6 6.0L short­block and it didn’t blow up. Three weeks later, I wrapped up my next land-speed-rac­ing short-block, which is des­tined to make “only” 1,000 hp at “only” 17 psi and it has about $10,000 worth of beefy parts. Why? You can bet I’m ask­ing my­self the same ques­tion.

This started in 2011 when Richard Hold­ener con­ceived a HOT ROD story called “Big Bang The­ory,” wherein a 4.8L truck en­gine made 1,203 at 26.8 psi on an en­gine dyno. Hold­ener has since done a bunch of other “Big Bang” en­gines on ni­trous and boost, push­ing used LS short-blocks well north of 1,000 hp be­fore hav­ing to mop the crank off the floor. These days, per­haps hundreds of peo­ple have proved the mer­its of SBE (stock bot­tom-end) LS en­gines run­ning be­low the break­ing point in 8-sec­ond drag cars or at least in chas­sis-dyno ses­sions. The high­est known power on an en­gine dyno is Hold­ener’s 1,543hp Gen IV en­gine, and you’ll see the story here in HOT ROD soon and also in the En­gine Masters video se­ries on Mo­

It should shock you that a 200,000-mile en­gine with cast pis­tons, pow­dered-metal rods, and a cast crank can with­stand about the same power as an early 1960s Top Fuel Hemi made blown on 100 per­cent nitro. How do LS en­gines en­dure it when 1960s-era OE en­gines won’t? My opin­ion: Stock cross-bolted mains, bet­ter cast­ings with fil­let radii on the crank, even the pow­dered-metal rods are stronger than old cast­ings, and the man­u­fac­tur­ing on cast pis­tons is bet­ter than it was. The head-clamp­ing struc­ture is bet­ter and MLS head gas­kets are stan­dard. To­day’s ma­chin­ing prac­tices are bet­ter, thin­ner pis­ton rings are su­pe­rior, and fac­tory EFI is so pre­cise that en­gines don’t wear like they used to. In high-boost projects, smart EFI tuners keep the en­gines out of det­o­na­tion, which is the num­ber-one killer of parts. With turbo boost, you can keep rpm be­low 7,000, and boost re­duces snatch load on the pis­tons and rods.

So why would you ever in­vest in qual­ity forged parts for your own en­gine? First, I’d say that these ab­surd dyno tests on SBE en­gines are a bit of a sideshow trick. The real world pun­ishes an en­gine more than a dyno does. It feels like an overly adult ar­gu­ment con­sid­er­ing how many LS en­gines have made hundreds of passes at 1,000-plus horse­power, but you have to con­sider the con­se­quences of en­gine fail­ure near the fin­ish line as you drive through oil and hurt your­self or the guy in the other lane.

It’s also my opin­ion that fewer peo­ple are ac­tu­ally rac­ing these com­bos than the in­ter­net would make it seem, and the ones who make lots of laps are smart tuners. Other guys are Dyno­jet­ting 1,000 rwhp and then just hit­ting the streets on ra­di­als and do­ing burnouts.

As for my megabuck Dart short-block with a Crower crank and rods and JE pis­tons? I plan to run it at Bon­neville, wide open for nearly 5 miles at high coolant temps. I can’t have a con­nect­ing rod change its mind and lead to an oil fire or wheel lockup at 260-plus mph.

That’s all I’ve got. Oh, and if you pre­fer your old Mopar or Buick to the belly­but­ton LS, or you want a stro­ker, or you’re build­ing an NA pow­er­house,

I’d still opt for the forged stuff.

I’d also use qual­ity parts for any road-course or en­durance ap­pli­ca­tion. Or any­thing with a roots blower or ni­trous. Yet I’m afraid I haven’t con­vinced my­self that a boosted junk­yard LS isn’t the best bang for the buck for any street/strip car be­tween 700 and 1,000 hp.

[ My Crower rods and JE pis­tons alone cost roughly 16 times as much as Hold­ener’s junk­yard short­block. But I’d do it again.

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