JakeFusion

iTrader: (7)

HPR is I guess HKE reborn with Erik Koenig over it.

On Corvette Forum, there have been about a half-dozen 468cid builds they are doing with Darton sleeved blocks and their custom 4.250" stroke crank. They are road race cars and have lived. But they are so big even with big Brodix LS7 heads and MSD intakes, they peak at 6300. Graphs look like FAST 102s on 427 Cathedral motors... just 100HP higher. 680/630 type numbers to the tire. So, I'm interested in something like that as it's in my budget, and it looks like one of the LSA blower cars with cam/heads. Just crazy stuff. I think the 440 might be more my style with a 4" stroke to be able to use current LS7 heads and MSD-type intakes a little better. And pretty much anything in the 427-454 range costs the same from them. But it's all custom spec from Wiseco/K1.

Anyways, Erik had a stellar reputation with HKE for a long while but it seemed to go a little south at the end as is wont to happen when a shop closes. And now there's been a case or two where poor machine work has ruined a few of these new motors.

Does anybody have any experience with them here?

Thanks

spanks13

iTrader: (5)

440 vs 468 is really going to come down to your intended usage and the rest of your setup. Just went from a SBE ls3 to a 416 and made minimally more power due to the Vic Jr. being maxed out, but tons more mid-range. Had to pull 6 degrees of timing out of the launch or it literally was flipping over backward. Around a road course the 416 would be monstrously faster. Down the 1/4 mile the car is putting up similar ET's.

The shorter stroke and higher reving 440 could be more easily optimized with the top ends that are readily available, and may be easier to get down the track if drag racing is your thing.

If it is a street or road race application the midrange of the 468 will produce a faster and more powerful feeling car all things equal.

I've seen nothing but good things said about HPR, but corvette forum is an echo chamber.

Smokey B

^^^^

Che70velle

iTrader: (6)

qweedqwag

I just read a steller article about Eric, seems like he knows what he's doing. Here is the article, I'd let him build me something.
https://www.enginebuildermag.com/201...id-ls1-engine/

JakeFusion

iTrader: (7)

I know... I've asked Anthony their sales manager about the one pretty negative experience I saw there. I'll see what he says.

But that's where I'm at... the 427-440-454 is all the same price. Most of the really optimized setups are for the 427 (like the Ai Heads and RPM B-3 Cam and Tony's 265 stuff). They would just work a little better with the 440 with additional bore for added flow and would tame down some of the more aggressive cams a hair. But would still carry power pretty much the same as the added cubic inches and still 4" stroke won't do much to the power curve other than move it up 10-15 points. But I think your analogy for an LS3 to a 416 is a good one... the manifold becomes a choke point on these things. But the LS7 is a different beast than the LS3 or even Cathedral architectures, and why I've skipped right over the 408/416 stuff. Going from a 346 to a 408 is good for maybe 80HP realistically well-optimized to well-optimized 450whp-530whp.

And those gains are bigger than SBE LS3 to 416, because the 4" bore opens up a different class of larger/better flowing head. The LS3 already has that so you're only really seeing the the 40ft-lbs gain and maybe the 40HP gain on top just due to the increase cubic inches. But the difference from a 408 to a 427 is another 70HP. Because the LS7 architecture is just that much better. And price wise... it's less expensive to move from a 408 to a 427 than it is to move from a 346 to a 408. But still not cheap and less cost effective than a turbo...

Anyway, I do drive more on the street than anything. But getting down a 1/8 mile is also a thing from time to time. So, having extra midrange torque is a lot of fun. But being able to rev to 7500 is also fun. I know Tony has made more power going to a 454 over the 427 using the same topend package with cam timing changes. And even the HPR guys are seeing numbers jump from 620-630 to 660+ with torque numbers that jump from 530-550 to 620-630+ so it's definitely a noticeable jump for a modest increase in price. And if I wanted to optimize my setup and keep power below 6800, the 468 is just going to stomp everything...

I mean, those torque/power curves look like pulley'd down heads/cam LSA packages.

spanks13

iTrader: (5)

The 468 is the way to go for sure! I'd make sure to keep the cylinder walls thick enough for at least a couple hones.

JakeFusion

iTrader: (7)

I think you can take a Darton out to 4.200" so there's a hone or two in there.

Summitracing

He's one of the best and smartest LS engine builders I've ever met. Meticulous work.

JakeFusion

iTrader: (7)

I've always heard he was the best... and most of the products they carry now are specific part numbers for their builds. So it's not shelf stuff...

Tuskyz28

After seeing Erik build 408s that goes 9s in a F body cars with 5.3 heads done by Greg Good.... I say welcome to the elite team.

Steve - Race Eng

iTrader: (1)

4.185" on the dry liners. 4.1875" would be the absolute max. I would recommend so one hone would be it.
Erik does a nice job on these large cube engines. He has the components down to make these live.

JakeFusion

iTrader: (7)

Steve, thanks for that.

Are you doing the sleeves for Erik? Or is he doing those in house now?

Steve - Race Eng

iTrader: (1)

I've done the last three or four for him. I used to do all of Erik's blocks when he had his HKE shop a few years back.

GrannySShifting

iTrader: (10)

Erik has been the only guy I could trust to get it right over the last 15 years

Steve, any structural/strength differences in your opinion between gen3 and gen4 iron 5.3 blocks?

Steve - Race Eng

iTrader: (1)

I have a Gen III block here but no Gen IV to compare it with in terms of casting thickness. One known change is the Gen III uses the long bolts that extend to the bottom of the crankcase where the Gen IV uses the short bolts.

GrannySShifting

iTrader: (10)

That I know, but Im more concerned about main bulkhead strength, cylinder wall thickness for stuff making 1400hp+ see how far could go on factory block. The walls are @.210 thick vs .150 on the 6.0s i think, I dont trust mains on OEM alum block to stay nearly as rigid as iron ones would - using a short stroke center counterweighted crank to keep loads into the main caps down much as possible

JakeFusion

iTrader: (7)

Steve, do you recommend moving to an LS2 block for sleeving for additional power requirements over the Gen IV 5.3s?

Steve - Race Eng

iTrader: (1)

No for high boost applications, the 5.3 is stronger because the main bearing bulkheads are solid, no breather holes. It is difficult getting a decent 5.3 Gen IV casting. GM doesn't sell bare blocks. The only ones available new are factory rejects. I stay away from those. Too many issues with holes not machined, cam bearing installations screwed up, etc. Best to find a good used one. Casting number that I use most often is 12571048.

Steve - Race Eng

iTrader: (1)

The aluminum casting is more than twice as thick as the iron casting in the main bearing bulkhead area. They are holding up very well with Darton sleeves installed. These can be sleeved to 4" bore or less (the small bore sleeves are 3.875" from Darton) if there is some reason to go smaller bore. Max. recommended bore size for boost or nitrous is 4.155" with the standard LS7 Darton liner.
If you want an iron block, it is best to start with either the GM LSx or Dart LS Next casting. These have much thicker main bearing bulkheads and cylinder walls and will accept the LS7 style heads.
I'm a Dart dealer if you are interested in going that route.

Steve