5.7 Hemi Heavy Duty (HD) vs Overhead Cam Engine

[Wailin D]

It looks like they are bringing back the 5.7 Hemi. This would be an excellent opportunity to make some upgrades that I am calling the 5.7 Hemi Heavy Duty. Most of the upgrades can be done with existing Mopar parts. This would make a bullet proof 5.7 Hemi. See what you think below.

There are rumors that Mopar is working on an overhead cam V8. The advantage of an overhead cam engine is that you can control the cam timing of the intake and exhaust separately with individual cams. Something I learned from Reignited Cycle and Automotive YouTube site is that this can be done without having separate cams for the intake and exhaust (). In the 2008 Dodge Viper they put two cams within a single cam that enabled them to control the intake and exhaust separately with an overhead valve arrangement. Personally, this seemed to be a much better approach that keeps the identity of the Hemi rather than an overhead cam engine.

5.7 Hemi Heavy Duty (HD)

The majority of these parts come from the Mopar parts bin.

6.2 Hemi stock forged crankshaft (same stroke as the 5.7 Hemi)
6.2 Hemi stock forged connecting rods
Forged pistons – 5.7 Hemi pistons are smaller than 6.2 pistons – vendors Mahle, Wiseco, Manley
6.2 Hemi oil pump or better yet the Melling 10452HV
6.2 or 6.4 Hemi Exhaust manifolds
Camshaft and material upgrade – Cam within a cam controlling the intake and exhaust separately made of a billet core or other materials more durable than stock camshafts
Camshaft Lifters – Johnson Lifters

 

[cpearce]

Glad they are keeping the platform around, it is a great design. Good news for hotrodders!

 

[Murray]

If they can solve the "Mopar tick", I am all for it.

 

[DionR]

It looks like they are bringing back the 5.7 Hemi.

Based on what? I hear people say there are rumors, and even an article that thinks the Charger SixPack has a Hemi (it doesn’t), but nothing more than that.

 

[67Dart273]

I decided, before I bought the GMC that I want NOTHING AT ALL TO DO with a "V" engine and OHC. I don't care if it's v2, v4, v6, or V4406, if it's a "V" engine I want PUSHRODS

 

[DionR]

Part of the problem with the Hemi was emissions. So I think the next V8 should be based on the Viper and be an inline valve motor.

The foundation of a motor is air flow and the later Viper heads have been shown to be more than capable with ported heads over 400 cfm.

So do a V8 design using the Viper head as the foundation. Use the cam in cam technology, but maybe reserve it for the SRT motors and leave the current VVT technology on the more “base” motors. Use the current Hemi block as the base but make sure the pushrod angles match the new heads. And add direct injection. Bet it could break 550 hp NA easy.

That would give a smaller V8 that is cheaper to build, have better emissions and be way easier to fit in an engine bay.

I love the Hemi, but I bet a Viper based V8 would be a win-win in the end.

 

[67Dart273]

LOL, well wasn't the Viper sort of based on V8 Magnums? I mean the ports are way different, and not paired but they are still a pushrod/ wedge design.

 

[DionR]

LOL, well wasn't the Viper sort of based on V8 Magnums? I mean the ports are way different, and not paired but they are still a pushrod/ wedge design.

Sort of? The truck V10 was in the works before the Viper was a concept and it started as a 5.9 with 2 more cylinders. But look where the truck V10 ended design wise. It really doesn’t share much with the Magnum beyond maybe the piston design. No distributor, symmetrical ports and it even looks like they corrected the wonky pushrod angle.

And after the Viper team got done with the Viper V10, there isn’t anything shared with the truck V10 beyond maybe some bolts.

But yes, it is a pushrod motor. I think the LS/LT and Godzilla have proven there is still potential. And the designs are already done for the most part so (in my mind) the development costs to create a new V8 would be much reduced, it might be cheaper overall than the Hemi and the emissions would probably be better.

Just a fun idea, nothing I think the factory would entertain.

 

[Map63Vette]

So funny story, but someone did make a V8 Viper engine already (kinda). Conley engines was contracted to make some 1:4 miniatures of the original Viper engine for some promo stuff way back when. I know one exists, I think maybe 2 were fully built and parts have shown up here and there since then, but a foundry fire basically killed the project. However, since he had already done all the work he chopped two cylinders off and sold it as the "Stinger 609". So it's technically not the Viper engine, but you can definitely see the similarities. Gary Conley - The Miniature Engineering Craftsmanship Museum

So there is certainly some precedent for a V8 version of the engine...

 

[DionR]

So funny story, but someone did make a V8 Viper engine already (kinda). Conley engines was contracted to make some 1:4 miniatures of the original Viper engine for some promo stuff way back when. I know one exists, I think maybe 2 were fully built and parts have shown up here and there since then, but a foundry fire basically killed the project. However, since he had already done all the work he chopped two cylinders off and sold it as the "Stinger 609". So it's technically not the Viper engine, but you can definitely see the similarities. Gary Conley - The Miniature Engineering Craftsmanship Museum

So there is certainly some precedent for a V8 version of the engine...

Cool!

I know there was a European race team that built a V8 version using the V10 block because they outlawed the V10's. And that V8 still rocked the competition.

Just seems like Mopar is in dire straights and a V8 version of the Viper motor with some tweaks would be a cheap(er?) option than an entirely new V8. If emissions was truly a part of the demise of the Hemi, then a new Hemi might not be the best option. An inline valve motor with a smaller combustion chamber and less crevasse volume might be a better direction and they maybe have the foundation for such a motor in the Viper V10.

And I'm not saying it is a slam dunk no cost option. Even if they could use the Hemi block, it would need a new casting for the head and some kind of an intake. The big savings is in the development costs, which might or might not be a drop in the bucket in regards to total costs.

This idea has had me watching YT videos on Viper builds and such recently just to get a better idea of how they are built and designed. After doing so, I want a Viper even more than I did before. Such a cool car. That said, I don't think the smart move for Mopar is to just cut 2 cylinders out of the Viper motor and call it good. The motor looks too costly to build for mass production with the aluminum block and oil pump in the timing chain cover. But the Viper heads on the Hemi block seems very doable in my mind, enough so that I wonder if some yahoo in his garage couldn't do it on his own. I mean, if someone can put LS heads on a 351W or (even worse) an inline 6, why couldn't someone section a pair of Viper heads to remove a cylinder each and then tweak the bolt pattern to fit a G3 block?

To be clear, the only reason I can see for someone to build a Viper headed G3 block is because they want something different. I'm not sure it would be a straight up performance improvement and while a G3 is a tight fit in an A-Body I'm not sure it would be easier to build custom headers for a frankenstein build like that despite being narrower. At the same time, imagine the visual of a shortened Viper motor in an A-Body.

 

[Map63Vette]

Vipers are super fun, so if you get the chance I would definitely encourage it. I bought my 2004 to be my daily driver and have something like 138,000 miles on it now. They are built really well and don't wear out easy, plus they are generally pretty easy and "cheap" to maintain. Mechanically they are very straightforward and easy to work on. Tires and fluids are what rack up the costs. 11 quarts of oil each change and $1500+ for a full set of tires gets annoying, but could be worse I suppose. The bigger issue is just finding tires for them period as so many places are starting to discontinue them. It's getting closer to the point that the only tires on the market for them are race oriented, which isn't great for someone like me that uses the car nearly year round and in weather.

 

[67Dart273]

Zack Speed is the team that ran V10s as V8s There was quite a story on that and I posted it some time back. I was always amazed at how good the Vipers did in that stuff

 

[DionR]

Vipers are super fun, so if you get the chance I would definitely encourage it. I bought my 2004 to be my daily driver and have something like 138,000 miles on it now. They are built really well and don't wear out easy, plus they are generally pretty easy and "cheap" to maintain. Mechanically they are very straightforward and easy to work on. Tires and fluids are what rack up the costs. 11 quarts of oil each change and $1500+ for a full set of tires gets annoying, but could be worse I suppose. The bigger issue is just finding tires for them period as so many places are starting to discontinue them. It's getting closer to the point that the only tires on the market for them are race oriented, which isn't great for someone like me that uses the car nearly year round and in weather.

Probably have to come into some money before it is an option for me. But it is on the radar now if something weird happened.

 

[Map63Vette]

Probably have to come into some money before it is an option for me. But it is on the radar now if something weird happened.

I guess they are starting to go back up, but you can get some of the earlier ones pretty reasonable. The gen 1s are very rough and tumble cars, but are still super fun. My mom has a 94 that I still really enjoy driving, even compared to my hopped up 04. Mine is pretty much better in every way, but there's just something special about hers that makes it fun. You used to be able to find them in the 20s for one with some typical use on them. Gen 3s (like mine) you could find in the 30s from time to time, but that might have creeped up since COVID messed with the used car market. I made a spreadsheet of pretty much every Viper for sale in the US back when I was looking to buy mine. Listed year, color, miles, mods, price, etc. and started working my way through them to figure out what I wanted to pursue. Narrowed it down to two cars and pulled the trigger on mine because it had a couple of mods that I found more appealing.

People at work gave me grief all the time for it, but I only needed to drive myself to work and back, so I didn't need storage space, extra seats, crazy gas mileage, etc. Their brand new pickups cost twice what I paid for my car.

 

[DionR]

I guess they are starting to go back up, but you can get some of the earlier ones pretty reasonable. The gen 1s are very rough and tumble cars, but are still super fun. My mom has a 94 that I still really enjoy driving, even compared to my hopped up 04. Mine is pretty much better in every way, but there's just something special about hers that makes it fun. You used to be able to find them in the 20s for one with some typical use on them. Gen 3s (like mine) you could find in the 30s from time to time, but that might have creeped up since COVID messed with the used car market. I made a spreadsheet of pretty much every Viper for sale in the US back when I was looking to buy mine. Listed year, color, miles, mods, price, etc. and started working my way through them to figure out what I wanted to pursue. Narrowed it down to two cars and pulled the trigger on mine because it had a couple of mods that I found more appealing.

People at work gave me grief all the time for it, but I only needed to drive myself to work and back, so I didn't need storage space, extra seats, crazy gas mileage, etc. Their brand new pickups cost twice what I paid for my car.

It would have to be a coupe for me, not a fan of open cars and I don't like the look of the RT/10 with the top on them. Just me.

I did a quick search for coupe/GTS on AutoTempest and looks like the first gen GTS are starting at $60K and the next gen are starting at $70K. There was a 2013 down in Florida listed for $45K with 140K miles or something, but that feels like a scam based on the other prices I saw, but it was in a color combo I liked a lot.

For those prices, I would have to find a wrecked one and fix it over time as funding allowed. Or find a much better deal than I saw there.

 

[Map63Vette]

It would have to be a coupe for me, not a fan of open cars and I don't like the look of the RT/10 with the top on them. Just me.

I did a quick search for coupe/GTS on AutoTempest and looks like the first gen GTS are starting at $60K and the next gen are starting at $70K. There was a 2013 down in Florida listed for $45K with 140K miles or something, but that feels like a scam based on the other prices I saw, but it was in a color combo I liked a lot.

For those prices, I would have to find a wrecked one and fix it over time as funding allowed. Or find a much better deal than I saw there.

I know what you mean regarding coupes. I had a Jag XKR a while back and didn't care for the vert styling as much or the potential headaches of a soft top. The tough part with them was they only imported 1 coupe for every 2-3 verts, so it was just hard to find them. The gen 2 coupe prices are way inflated in my eyes, but it is what it is. They are the cars that are the bedroom posters for a lot of people now. Gen 3 had the coupes for one year (2006) that you might be able to get just a bit cheaper than the gen 4s, but they were semi special edition, so maybe not that much better. I've become more of a drop top person now that I've had my gen 3 for so long and appreciate being able to open it up every once in a while, though I have also looked at a hardtop for it. They really don't seem to be as troublesome with tops as other convertibles though as the entire panel over you head is solid, so it's almost more like a "convertible hardtop" than a true soft top.

 

[Dantra]

Interesting topic. Reality for me is, it will not be in any foreseeable budget of mine haha... well, I guess I am hitting the lottery soon, so there's always that.

When I see these youtubes, speculating so many different things, I always ask myself.. how much is this gonna cost if it actually does happen? Then I start thinking about how it will be before aftermarket follows. If you thought a gen 3 Hemi swap was expensive...

 

[DionR]

Interesting topic. Reality for me is, it will not be in any foreseeable budget of mine haha... well, I guess I am hitting the lottery soon, so there's always that.

When I see these youtubes, speculating so many different things, I always ask myself.. how much is this gonna cost if it actually does happen? Then I start thinking about how it will be before aftermarket follows. If you thought a gen 3 Hemi swap was expensive...

Not in my budget either. And last I checked, Mopar wasn't looking for input and has no idea who I am so it's all nothing more than a "what-if" anyways.

But I will admit I am more interested in a Viper than I was. Not anything in the realm of reality either, but fun to daydream.