Gen 4 Heads on Gen 3

[04BlackSRT10]

This post is directed towards Viper Specialty, as I know his company does this conversion, but anyone else can chime in also if they have info. What exactly is involved in putting Gen 4 heads on a Gen 3? I know they won't just bolt on, and have different exhaust ports. Is it worth it to do this aside from the superior looks of the Gen 4 top? What would be the approximate cost to have this done? I know you can run a Gen 5 manifold if you have Gen 4 heads, so that would likely be what I go with if I decide to do this.

 

[MoparMap]

Mopar made a kit for this as well at one point. I believe the biggest changes were the intake setup as they had a sort of hybrid gen 3/4 unit with a cable throttle body since the gen 4 and 5 are both drive by wire. I know there is more to it than that, but that was the biggest "custom" piece that stands out to me. The rest I think were effectively off the shelf parts like the heads and exhaust manifolds. The part number was P5156137. Here is an old listing for one that details what all was in the kit: https://www.viperpartsrackamerica.c...r-v10-150-hp-performance-upgrade-kit-p5156137. Sounds like pretty much everything on the top end gets replaced (heads, intake, fuel rails, injectors, etc.). Sounds like ~150 hp gain, though I think you can get that with gen 3 heads with less work if you really wanted to. I know just a cam alone in my car (a Viper Specialty one actually) pumped it up to nearly 600 crank horsepower. There have been a few builds on here that have dyno'd 600+ at the tires with ported heads and a cam, so depends how patient you are and how much you feel like replacing.

 

[Viper Specialty]

This post is directed towards Viper Specialty, as I know his company does this conversion, but anyone else can chime in also if they have info. What exactly is involved in putting Gen 4 heads on a Gen 3? I know they won't just bolt on, and have different exhaust ports. Is it worth it to do this aside from the superior looks of the Gen 4 top? What would be the approximate cost to have this done? I know you can run a Gen 5 manifold if you have Gen 4 heads, so that would likely be what I go with if I decide to do this.

The short version, is a lot of machine work on the heads, modified manifold and mechanical throttle conversion. Generally I wont go into exact details, because information has more value than the components... and a LOT of people, vendors included, arent even aware of the specifics and are literally still building time-bombs seemingly unaware of their mistakes.

Yes, its absolutely worth doing. Looks are only a bonus.

Personally I am not a huge fan of the G5 manifold, but thats personal preference.

Cost I honestly cannot tell you... we haven't been building engines for a few years, and costs have gone sideways since. I hope to be back at it this winter, and a couple of these packages are exactly what I had wanted to build as I am sitting on a pair of partial kits up in NY right now that were being accumulated before I shelved engine work and moved to FL.

 

[04BlackSRT10]

Personally I am not a huge fan of the G5 manifold, but thats personal preference.

I do think it's odd that they went away from metal for the intake manifold on the Gen 5. I've seen a video where a heavily modified Gen 5 literally blew a hole in his manifold from using NOS. I highly doubt that would have happened with the Gen 4 intake.

 

[Goggles Pizano]

I do think it's odd that they went away from metal for the intake manifold on the Gen 5. I've seen a video where a heavily modified Gen 5 literally blew a hole in his manifold from using NOS. I highly doubt that would have happened with the Gen 4 intake.

Cost, easy of manufacturing and met the performance requirements. Why would I care about what mods you may do in the future and not meet the MSRP price point? No difference then them changing from forge pistons on the gen2s and carrying it on to gen3/4.

You want to modify then go ahead, just know what you are doing and if they blew the manifold apart then they do not know what they are doing. Look at the TT builds that are built by those that know. Gen4 intakes or custom intakes.

 

[Viper Specialty]

Cost, easy of manufacturing and met the performance requirements. Why would I care about what mods you may do in the future and not meet the MSRP price point? No difference then them changing from forge pistons on the gen2s and carrying it on to gen3/4.

You want to modify then go ahead, just know what you are doing and if they blew the manifold apart then they do not know what they are doing. Look at the TT builds that are built by those that know. Gen4 intakes or custom intakes.

There has been numerous G5 manifold failures on TT builds. In high-boost cars they revert back to G4 manifolds... I think you may have been implying the same.

Total cost-cutting measure.

 

[Steve M]

The composite intake makes a lot of sense for NA applications - lighter weight, less heat transfer, and from what I remember, slightly out performed ported Gen 4 units on the dyno.

Considering the majority of Gen 4/5 cars aren't running forced induction setups, it seems like a no-brainer to me.