GM rockers on Gen 4 5 vipers

[T/A KID]

Was looking at the rockers on my gen 5 viper and they look VERY much like lsx rockers…. I can do a trunion upgrade on some ls7 (exhaust valve on these appear to match the slight offset the viper uses) or use new style LTx rockers which are 1.8 ratio as well… this could be a cheap option for vipers and gain around .30 valve lift on the intake and exhaust..

Heard a rumor that this can be done, anyone have any experience with doing this?

[Aevus]

stock cam?

what is the stock cam's lift?

[StrokerAce]

This was an old way of helping small block Chevys. Throw the 1.6 on the exhaust but I put 1.6 on my one SBC instead of the 1.52's for both intake and exhaust.

Was JUST thinking about this earlier today while reading another thread on here. As long as you don't exceed flow capabilities of the heads, and that you don't kiss a piston. lol

[T/A KID]

Stock lift is under .500 on exhaust and I believe it’s only .520 on intake stock..

Duration is roughly 232/224
Not sure on LSA but my guess be around 116

[T/A KID]

With 10.2 CR with that valve lift PTV is light years away lol…

I’ve tuned 11.5 CR vipers with .620 lift with stock pistons no fly cut needed

[T/A KID]

This was an old way of helping small block Chevys. Throw the 1.6 on the exhaust but I put 1.6 on my one SBC instead of the 1.52's for both intake and exhaust.

Was JUST thinking about this earlier today while reading another thread on here. As long as you don't exceed flow capabilities of the heads, and that you don't kiss a piston. lol

I plan to borrow some ls7 rockers from a shop and do some measuring.. as long as the tip of the rocker measure up on the center of the valve it should work.

[Aevus]

Stock lift is under .500 on exhaust and I believe it’s only .520 on intake stock..

Duration is roughly 232/224
Not sure on LSA but my guess be around 116

yeah I think that's about right, similar as gen3/4

I guess engineers at Dodge were more concerned about emissions than performance

[Aevus]

I plan to borrow some ls7 rockers from a shop and do some measuring.. as long as the tip of the rocker measure up on the center of the valve it should work.

Personnaly, I'd rather put shaft mount rockers

https://tdmach.com/product/rocker-arms/

or

https://www.jesel.com/rockers

along with conical springs and Ti retainers (as I did actually) and while at it you change the valves for Ferrera's or similar

even without a cam swap, you'd probably gain some HP between 6,300-6,600 rpm or so

[Aevus]

With 10.2 CR with that valve lift PTV is light years away lol…

I’ve tuned 11.5 CR vipers with .620 lift with stock pistons no fly cut needed

as long as you don't change the cam for longer duration one, you might be okay.

I couldnt go more than 10.9 CR and somewhat limited lift on mine because of my 248/256 duration

[T/A KID]

Personnaly, I'd rather put shaft mount rockers

https://tdmach.com/product/rocker-arms/

or

https://www.jesel.com/rockers

along with conical springs and Ti retainers (as I did actually) and while at it you change the valves for Ferrera's or similar

Even without a cam swap, you'd probably gain some HP between 6,300-6,600 rpm or so
With the rest of the engine breathing, yes I’d say 200-300 rpm higher then stock be good for power with these mods certainly.

100% shaft mount rockers from Jessel or similar as Fantastic, but 100% overkill for someone just wanting to put on some easy bolt on power (naturally springs replaced while heads are off). We are talking about having a 1.8 rocker done with trunion upgrades (no needle bearings like the factory rockers) for around $400… shaft mounts usually 3k+

[T/A KID]

Aevus what’s your LSA on that cam?? You programmed with hp tuners or arrow PCM?

[Aevus]

With the rest of the engine breathing, yes I’d say 200-300 rpm higher then stock be good for power with these mods certainly.

100% shaft mount rockers from Jessel or similar as Fantastic, but 100% overkill for someone just wanting to put on some easy bolt on power (naturally springs replaced while heads are off). We are talking about having a 1.8 rocker done with trunion upgrades (no needle bearings like the factory rockers) for around $400… shaft mounts usually 3k+

They're expensive, no doubt, and the 12-20 weeks (!) waiting list is sure not fun

your solution is probably the most cost-effective, along with the higher CR ...
Sorry my mind is still deep in the high-RPM project I'm still playing with :witless:

[Aevus]

Aevus what’s your LSA on that cam?? You programmed with hp tuners or arrow PCM?

details all here:

https://driveviper.com/forums/threads/28790-What-really-limits-our-engines-to-rev-higher?p=463669&viewfull=1#post463669

Gen 3 though

[T/A KID]

What a nice build!!! I assume those are 69# fast injectors?? Remember what your duty cycle was??

Going to put some demon injectors in mine for E85, they flow roughly 66.7lb hr

[Aevus]

What a nice build!!! I assume those are 69# fast injectors?? Remember what your duty cycle was??

thanks, can't wait to have it properly tuned and see what kind of torque curve I'll get with all that...

Torrie from Unleashed sold me those, don't know the details sorry. He said I could keep my stock gas pump but had to change the injectors...

[Aevus]

too bad we can't get E85 easily in Canada... anyways, what kind of mods are needed on a Viper to run on that?

[T/A KID]

Not sure how good the rear pump is on gen 3 (I’m sure yours is upgraded already), but you have a fairly large injector already and at your power level I bet e50 or higher be worth 30rwhp…

Where I’m located e85 is available at most stations, roughly 2.30 a gallon right now. It’s winter Blend (68-70%) year round for us, which I happen to like since I know it’s predictable and I can set the stoich ratio in the tune accordingly and it saves me a little fuel on the fuel system side.

My plan for my car is to change injectors only, keep stock pump an run pump e85

[Old School]

I did a cursory investigation of installing LS7 exhaust rockers on a Gen3 a year or 2 ago. Bought a single from Rockauto for ~$12. The geometry wasn't quite right. It ran out of radius on the tip at max lift. Might work with roller tips though.

[T/A KID]

I did a cursory investigation of installing LS7 exhaust rockers on a Gen3 a year or 2 ago. Bought a single from Rockauto for ~$12. The geometry wasn't quite right. It ran out of radius on the tip at max lift. Might work with roller tips though.

Nice! If I recall right the gen 3 has to have a pedestal installed??? If so that may make it too high as well?
Not sure what valve angle is either on a gen 3 head???

Good thing about ls7 heads and gen4-5 heads there 12 degree valve angle..
I have some pics I’ll see if I can post them!

Yes I thought about aftermarket roller tip, that give it little more surface area to work with over the factory tip!

[T/A KID]

Here is Ls7 1.8 rockers

53109

Factory G5 1.7 rocker

53110

[Ramtuff]

I think the exhaust offset is a bit more on the ls7 than the Gen 4-5. If you look the one side is straight and only angled on the other side. On the Gen 4-5 exhaust that same side has a sleight angle. I have an unknown roller tip set (that I believe are ls7) that came with a set of heads I purchased, they are about .125” off center of the valve tip.

[T/A KID]

Ramtuff great info, have any pics of your setup?? I can probably tell from pics what rockers you have!!

Worst case a $200 upgrade and do 1.8 rockers on intake side still make a little power ;)

[Ramtuff]

It would be nice to know what they are.
53113
53114

[T/A KID]

Looks like Hughes engines (dodge performance) sells those