RHS vortec heads

[Z71tweeker]

Im getting ready to build up my L31 and i am lookin around for some heads. I want to make some better torque and still add some hp too. These RHS heads seem pretty good and supposedly flow 27cfm more the the 906s at .500 . They have a 170cc intake runner, 64 cc combustion chamber and 2.020 /1.6 valves. Does anyone have these? I just dont want to go to big on the intake runner and loose torque. Im plan to keep my engine a 350.

Here is the desciption in summit. http://www.summitracing.com/parts/CCA-12410-01/

[silvermonte]

im in the process also of building my L31 into a 383 and was thinking about a diffrent set of heads, but what im wondering is for the money would u be better off just gettn your stock heads machined for the larger vavles and and while your at it do some grinding for the pushrods for a set of 1.6 rockers, might save u some money for the same amount of flow, i havnt been able to find any flow numbers yet to what stock head get with bigger valves im fairly new to this site and havnt gone thru all the threads yet

[Z71tweeker]

I think i may just go with these heads. I found them assembled for $699.98 with 2.02 1.60 valves and a 170cc intake runner that should be good for torque. Thats for the set. I dont see how i can go wrong since it would cost at least over half that to rebuild the stockers to that valve size.Now i just have to pick a cam. Does anyone have any input on a cam for a low end 355?

[93ChevyTBI]

my cam is made for low-end and it's great. However, I do miss the ocassional top-end scream. Maybe one size bigger wouldn't be bad...08-411-8.

[soonerZ71]

Originally Posted by Z71tweeker

Im getting ready to build up my L31 and i am lookin around for some heads. I want to make some better torque and still add some hp too. These RHS heads seem pretty good and supposedly flow 27cfm more the the 906s at .500 . They have a 170cc intake runner, 64 cc combustion chamber and 2.020 /1.6 valves. Does anyone have these? I just dont want to go to big on the intake runner and loose torque. Im plan to keep my engine a 350.

Here is the desciption in summit. http://www.summitracing.com/parts/CCA-12410-01/

The L31 heads that you have are capible of supporting 400+ hp right out of the box.

The flow data that I have seen that comparing the RHS vortecs to the 062/906 vortecs show that they flow virtually the same from .100-.400 lift with the only advantage being the higher flow peak lift by the RHS heads.

The fact is that you only see "peak" flow once in an engine cycle. for example if your cams peak lift is .510, it sees that lift once while it sees lift from .001-.509 twice thus making midlift flow much more important than peak flow.

Anyway, the point im trying to make is that you are not going to be ganing much by going to the RHS vortecs over the chevy vortecs. If you are putting them on an otherwise stock motor there would be virtually no gain at all.

[Z71tweeker]

After reading this I dont know what to do. Do most people just put larger valves in the stockers? Or is there someone that does make an better aftermarket vortec? I wish GM performance would sell an aluminum vortec head that had a 170cc intake runner. All i can find is 200cc runners.
If i were to keep my stock vortec heads, could someone recommend a cam? So far my setup is going to a 4bolt 355
gibson stainless headers
75mm Throttle body
Custom tune
1.6 rrs
K&n CAI
Unknown cam
Unknown heads

Originally Posted by soonerZ71

The L31 heads that you have are capible of supporting 400+ hp right out of the box.

The flow data that I have seen that comparing the RHS vortecs to the 062/906 vortecs show that they flow virtually the same from .100-.400 lift with the only advantage being the higher flow peak lift by the RHS heads.

The fact is that you only see "peak" flow once in an engine cycle. for example if your cams peak lift is .510, it sees that lift once while it sees lift from .001-.509 twice thus making midlift flow much more important than peak flow.

Anyway, the point im trying to make is that you are not going to be ganing much by going to the RHS vortecs over the chevy vortecs. If you are putting them on an otherwise stock motor there would be virtually no gain at all.

[soonerZ71]

Vortec heads require a few little mods to allow them to run a cam with over .480 or so lift. There are many ways to do this. here is a link to tell you everything you ever wanted to know about modifying them.

http://www.nastyz28.com/forum/showthread.php?t=56505

Most of the info is on the first 3 pages.

As far as valve size, your 1.94/1.50 valves are fine. Unless there will be some major porting and polishing done on the heads, the gains from 1.94/1.50 to 2.02/1.60 will be very minimal.

As far as a camshaft, something like this seems like it would be a good choice:
http://www.summitracing.com/parts/CCA-07-304-8/

[05BlackCrew]

I run the RHS pro torkers on my 383 with the 218/224 495/503 cam.

[Z71tweeker]

How do you like them? Im also interested in what kind of mileage you get with your truck when you baby it.

Originally Posted by 05BlackCrew

I run the RHS pro torkers on my 383 with the 218/224 495/503 cam.

[silvermonte]

Originally Posted by soonerZ71

The L31 heads that you have are capible of supporting 400+ hp right out of the box.

The flow data that I have seen that comparing the RHS vortecs to the 062/906 vortecs show that they flow virtually the same from .100-.400 lift with the only advantage being the higher flow peak lift by the RHS heads.

with comparing them, was that taking the stock heads with the larger valves in them, or the stock vavles? im aiming for 400hp give or take im not to worried about what the end result is, but i would just like to know that my 383 will be gettn enough air in it, and while i have the motor apart it wouldnt be that hard to get the work done to the heads, or if i really should just leave them stock, they have a 3 angle job done and z28 springs in them already

[soonerZ71]

Silvermonte,

Yes, that was a stock set of vortec heads with stock valves.

With the right cam, the stock vortec heads ought to give your 383 400hp potential. That being said, personally I would take the time to pull the valves and do a bowl blend and a little valve guide trimming on the exhaust side while you have the motor apart.

The main advantage that the RHS heads have Imho is that they are already machined for screw in studs and guideplates and have good springs on them out of the box. Just my opinion.

[05BlackCrew]

My stockers were cracked. RHS was the cheapest option at the time. They have lots of potential.

Fuel milage varies.
I got 17mpg on a road trip. My truck has also never been tuned.

Wes

[silvermonte]

i was lookn around and found these heads on ebay, they dont seem to bad for a set of aluminum heads,what im wondering is how much of a change the 190cc intake ports will change everything, thats gettn to large i would think, what do u guys think

http://cgi.ebay.com/ebaymotors/NEW-C...Q5fAccessories

[Z71tweeker]

I saw those also. I called the company and asked them a few questions about the heads. I guess they are made by an austrailian company. Wouldnt say who. They said they are made specificly for truck applications but the werent advertised that way and they were going to change that soon. I was kinda leary about the 190cc runners also. I think a smaller runner would be better for torque from what i understand. Also something go keep in mind is that these heads require longer pushrods because of a thicker head. Otherwise, they prolly wouldnt be a bad bang for the buck if you werent all about low end.
I was going to just rebuild my stock heads but buy the time i priced out what it would cost to completely rebuild and put differnt springs on along with screw in studs, It was gunna be as much as the rhs heads. So i just ordered some assembled RHS heads last night. I' ll let you guys know how it runs with my CCA-08-411-8

[Aloicious]

I recently put on some RHS heads, they're not the oversized valve ones though. can't give you much info on how they run though because I haven't started the truck with 'em yet.

[james_8997]

IMO, i spent about $550 on my stock heads(vavle job, springs, porting and polishing) and still dont hace screw in studs. if i could go back, i would have bought the RHD heads

[93ChevyTBI]

Originally Posted by Z71tweeker

I' ll let you guys know how it runs with my CCA-08-411-8

Let us know how that cam runs. You running a 355 or 383? There'a guy on here running it in a 383 but I'd really like to know how it performs in a 355. Mine is one size smaller. I almost feel like I could have went one size bigger.

[Z71tweeker]

Originally Posted by james_8997

IMO, i spent about $550 on my stock heads(vavle job, springs, porting and polishing) and still dont hace screw in studs. if i could go back, i would have bought the RHD heads

Yah same here, i was gunna have 500+ in them without the studs being switched to screwin type. They wanted 200 more for that labor alone. So i would have been over 700 bucks. I bought the set of rhs heads with the 2.02 and 1.6 valves. Ill let you guys know how it runs in the 355 in a couple weeks.

[nick383]

05BlackCrew, which ones are you running? The stock replacement ones or the 2.02 valve ones? Any improvement over the stock vortecs?

[05BlackCrew]

Originally Posted by nick383

05BlackCrew, which ones are you running? The stock replacement ones or the 2.02 valve ones? Any improvement over the stock vortecs?

The 2.02/1.60. I could not tell you if there was any difference. I bought the truck with a spun rod bearing, then built the 383 using those heads.

Wes