Dodge 8.0 Differences?

[PovertyPony]

I know this topic has been beat to death- but what is the extent of differences between the 8.0 found in the Viper and the 8.0 "Magnum" engine found in Rams? I've been entertaining the idea of the Magnum for another project and wondering how much knowledge would carry over.

Now I know the answer is "they're totally different." They were separate but parallel programs at Dodge both based on the old LA platform. But the question is how different? I know they don't share any parts. But is it like the 5.4 found in the Cobra R or GT compared to the 5.4 found in F150s, where they don't share any parts but they're the same platform, or is it more like the 351 Cleveland compared to the 351 Windsor, where they have absolutely nothing in common but the same displacement? (Ignoring Cleve-or hybrids.)

In particular I wonder about the valvetrain and rotating assembly, since the truck versions seem to leave a lot on the table with those.

 

[MoparMap]

I had thought they said the only real similarity between the two was bore spacing or something like that. I think there were only a half dozen part numbers or so that were common between them. That being said, since the 8.0 was based on the LA, I'd wonder if it wouldn't share more in common with the Magnums when it comes to parts. One other thing with the Viper, it might not share actual part numbers with earlier engines, but sometimes those parts do interchange. One example I can think of is the lifters. The Viper lifters are a different part number than the LA lifters, but in theory they are the same parts dimensionally. I believe the Viper ones are held to a much better tolerance though, which could be one reason they have a different number. So Viper lifters could be used in other engines, but other lifters may or may not work in the Viper based on how well they were made.

Generally speaking though, changing from iron to aluminum is going to affect a whole lot of design parameters. Different thermal expansion and strengths are likely going to dictate different structural designs and interacting components.

 

[PovertyPony]

That's exactly what I'm driving at. I've seen guys use rockers, pushrods, and other valvetrain parts from the Viper engine in the truck one- both basically LA based stuff. And same thing with the other engines I mentioned: the GT lash adjusters and followers were different than the run of the mill truck parts, but they fit in place and were a popular upgrade. Same deal with both the Ford Modular and GM LS engines with iron vs. aluminum. Totally different parts, but same families so you could mix and match. Not to mention all the purpose built parts that would be different between a truck and sports car engine, even if they're interchangeable. It would be no surprise the rods are heavier for the lower RPM, higher volume truck versus the higher revving, higher cost Viper, but are they compatible?

 

[Viperhunter]

Apparently Hall of Famer **** Winkles who helped develop the V-10 is suppose to be at this event in Pittsburgh. Might be pretty close to you. Could probably get some one-on-one time with him and hear it from thee man.

2022 Spotlight On Dodge Viper | PVGP

Dodge Vipers have been a staple at the PVGP Historic Races since Jim and Kathy Stout purchased the track in 2011. They have been racing their SRT Vipers there

pvgp.org

 

[PovertyPony]

Just a follow up to this one as I ended up taking the plunge and snagging a truck one for another project.

Some of the key differences include-
Cast iron material: Holy **** is this thing heavy
Block mounts: The Viper version uses an "ear" mount more like the old LA engines, whereas the truck has a pad mount that goes to your typical "spool" type mounts. If you're thinking of swapping something with an old LA, it would actually be pretty easy to use a Viper block versus a truck one.
Bellhousing pattern: Definitely seems to use a different bellhousing pattern, looks like the same as the one used in the 6BT trucks. Makes sense since they used the same transmissions between the two.
Accessory drive: Obviously different for packaging reasons, but similar serpentine setups.
Valve covers: Different, but haven't figured if they're interchangeable yet. The truck ones have provision for coil mounts.
Intake manifold: Obviously the truck has a much taller one with stupid long intake runners, making for incredibly low RPM peak torque. Haven't determined if they're interchangeable yet.
Exhaust manifolds: Obviously different rear exit on the truck. Same exhaust port and gaskets though.
Valvetrain/timing: I haven't measured anything but they sure look similar. Obviously cam specs are going to be way different.
Controls: Truck one is batch fire, waste spark. ECUs are different, but externally identical. Not sure how much is similar internally.
Internals: I probably won't get a chance to examine those any time soon (I hope.) I went a different route and rather than trying to improve the internals I decided to take advantage of the 8.6:1 CR, and cram a bunch of boost down its throat.

I still need to take a look at the injectors to see if they're different and by how much.

 

[GTS Dean]

The water pumps share identical bolt patterns from G1 to iron truck, but the inlets/outlets differ somewhat. Drive pulleys are about 1/4" different in projection from the back fl_ange.

 

[MoparMap]

I watched a YouTube video recently where a guy did a teardown of a trashed truck V10. He did a Viper style one earlier as well, but I believe it was gen 3 (maybe an SRT10 truck as well if I remember the oil pan correctly). I was amazed just how different the two really were as I've never seen an iron truck V10 before. Then again I haven't actually taken apart a gen 1 engine either, but just on the face of it I don't think much swaps over at all. I think I recall the only commonalities between them being something like bore spacing.

 

[BoondocSaint]

I watched a YouTube video recently where a guy did a teardown of a trashed truck V10. He did a Viper style one earlier as well, but I believe it was gen 3 (maybe an SRT10 truck as well if I remember the oil pan correctly). I was amazed just how different the two really were as I've never seen an iron truck V10 before. Then again I haven't actually taken apart a gen 1 engine either, but just on the face of it I don't think much swaps over at all. I think I recall the only commonalities between them being something like bore spacing.

I've seen those videos in my suggested YouTube videos, but never got around to them. Seeing a tear down of the two variants definitely has me curious.

 

[Fusion Works]

I know this is digging up an old thread, but I have some info I can contribute as I am in the middle of a V10 build now.

The Gen 1 Viper cam shaft and the Truck cam are different in that Chrysler used a goofy cam bearing size pattern, I think for production purposes, but the #1 cam bearing is 2.093in and they step down from there with #6 being 1.920in diameter. Viper uses the standard size 2.093 front to back, at least according to my Gen 2 Viper manual. I have a NIB MOPAR gen 1 Viper cam in bound to make closer measurements.

The lifter dimensions should be all the same. I am definitely sure there is some higher standards for the Viper lifters as those would need to fit more closely in the aluminum block and deal with different clearances based on heat. The iron block wouldn't expand the lifter bore as much thus they probably could use looser tolerances as well as the truck redline of 4500 vs the Viper of 6000-6500.

I wish I could get my hands on a Gen 1 Viper crank to compare dimensions to the truck crank, but I suspect they are similar, Viper is probably forged in Gen1 vs truck being cast. I think however the dimensions of the cranks are VERY similar. Rod bearings are the same size, mains are about .00013-.00018 difference in size. Viper is slightly larger, so you could possibly fit the Viper crank into the truck block. Need to get my hands on a crank to compare. Would like to get a Gen 4/5 crank due to the proper 60-2 trigger wheel instead of the goofy 5 pair like the early engines.

Heads, intake, etc are completely different. Viper has an closed valley, truck uses intake to cover lifter valley. I think Gen 1 Viper rockers are the same stamped design but I don't have Viper ones in hands and kinda don't care. I am more interested in the later model roller rockers as they have a higher ratio, 1.7-1.75 and a roller trunnion. Think I can adapt those to work on the truck heads.

Rod stroke ratio is the same in the Gen 1 Viper and the truck engine. Rods are different as mentioned above. Not sure why truck uses rods of such substantial size compared to Viper. Even the regular LA could have benefited from the lighter rods. Think of the money that Chrysler could have saved using the same lighter rods for all the V8 and V10 engines.

Deck heights are different, bore spacing is the same. For some reason truck block is quiet a bit taller. Obviously there weren't space constraints in the truck application and I guess they didn't care about extra deck height. Piston pin heights are much different Viper has a shorter piston. Truck has aluminum slugs that weigh 14 tons.

Bell housing pattern on truck block is same as Cummins. This allowed use of the same bellhousing and thus common usage of the truck transmissions across platforms. I have swapped a G56 six speed into my truck and its LIGHT years better than the NV4500. Both transmission are absurdly heavy, but built to tow a house, not move a 3000lb super car at the speed of sound.


I have more info, if anyone is interested.

 

[MoparMap]

This is all super interesting, thanks for sharing! Always novel to see just how much really changed between the two to help put that argument to bed about the Viper having a truck engine.

 

[Fusion Works]

It drives me nuts (as it does many of you) to hear that comment. "Its just a truck engine". Stupid people will always be stupid people.

The Viper engine is special all by itself. Its not the truck engine but it is closely related. That is also not a bad thing. Its kinda funny looking at most of the new "Big Gas" engines from Ford, GM, and Chrysler, they have a power band similar to the first Gen Viper. They all make peak torque and HP in the 4000-5000rpm range instead of like the Magnum V10 which makes its 450lb-ft at 2400. While I initially wanted to knock the truck engine the more I dig into it, the more I learn about the things that actually make this cast iron lump special, especially compared to its competition at the time.

 

[Fusion Works]

Got the Gen 1 Viper cam in hand and compared it to the truck cam. I suspect the Viper cam could be made to work in the truck engine, but its not just a plug and play. Would definitely need to align bore all the cam bearing journals on the truck engine to match the #1 bearing bore size to remove the 6 different bearing sizes. Viper cam uses the same size for all journals like a proper cam should. Also need to make a snout extension on the Viper cam drive end to line it up with the cam gear and thrust plate. All of this is doable, but not by the average joe.

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