85Iroc-Z

iTrader: (4)

I was thinking about buying a set of the 113 casting # corvette heads for my car, but had a few questions.
1. Are they a direct bolt-on? I know the EGR set up is different, but does anything else need to be changed?
2. Can I use the head bolts from my 416's?
3. What kind of performance gain could I expect over my 416 heads?
4. What is there max valve lift?
Thanks

five7kid

iTrader: (14)

They bolt on. There is no exhaust cross-over passage, which feeds the EGR valve, as you noted.

You should use washers under the head bolts. New bolts isn't a waste of money.

They have larger intake valves than 416's. You'll lose heat through the aluminum (lower effective compression ratio - that's why they have 58cc chambers for a 350 vs. the normal 64cc chambers for 350's). Performance gain is pretty much a wash.

Going on a 305?

85Iroc-Z

iTrader: (4)

Yeah, they would go on my 305. About how much would my compression ratio drop? Could you give a guess of an approxamite performance gain? Also, for the egr, instead of buying all the external stuff from a corvette, could I simply just remove the egr valve and install a block off plate?

skirkland1980

iTrader: (2)

i wouldn't expect any gain in power. do you have access to a 350?

skirkland1980

iTrader: (2)

yeah, homemade blockoff plate. it may not hurt to leave it on

85Iroc-Z

iTrader: (4)

I dont have access to a 350 right now. I want to build a 383 eventually, but I was just looking for another upgrade for my 305 in the meantime.

anesthes

iTrader: (12)

Those heads are ok for a production car. I'd be concerned about using them on a 305, you know, the car might actually go slower.

I think you should hold off.

-- Joe

luvofjah

iTrader: (2)

Same CC as the 305 TPI heads, no compression lost... with the aluminum, you can bump up the timing... I've read through here that many people have put these on 305's and gotten improved times....almost a full second on some reports, but no "loss" of times... ???

Rafael

anesthes

iTrader: (12)

Right, but it's aluminum so your thermal loss is much higher, so the car will go slower.

Yes you can add more advance, but will it overcome the loss is a good question. Normally when using aluminum heads, you target compression to be a half to a full point higher to get the same output.

-- Joe

luvofjah

iTrader: (2)

Aha... so if I find a nice set, I should use them for my Procharged 305 ???

Raf

tony_cogliandro

iTrader: (3)

i think 57kid knows more about this topic than most. he and i have disagreed on whether you should alert smog ***** by having it look different under the hood, but he is right on about the power loss and them being alunimum.
why not just spend the money you would on those heads and work the ones you have? they have a lot of potential and there are plenty of sites on how to do it right. probably more than a few written by 57kid.

anesthes

iTrader: (12)

Move.

-- Joe

tony_cogliandro

iTrader: (3)

im sure you had some point you wanted to make but it escapes me. want to try again, im willing to read it even if it does not make since. [yes i know its sense]
and do you guys in salem still burn people?

anesthes

iTrader: (12)

That was Salem, MA not Salem, NH and in reality most of the executions took place in what is now called Andover, MA as it was all "Salem Village" during English rule.

My point was, if you don't like the smog *****, move out of CA.

-- Joe

five7kid

iTrader: (14)

Technically, the emissions requirements apply to all 50 of the United States, regardless of the local inspection or enforcement.

If someone gained power putting 113's on their 305, one or more of the following was true: They started with swirlport heads; there was something wrong with the heads they removed; they did other things such as cam change, headers install, porting, etc.

You would get better gains putting Vortecs on. Yes, you'd lose static CR, but as was already noted, the effective CR would remain the same as with the 113's, but the improved flow and combustion chamber design would make up for the loss of CR. Of course you'd need a different intake manifold. And, you could shave the heads to return the static CR to stock. As you might have already deduced for yourself, these also would not be legal in any of the 50 United States for street operation.

New2Chevy

iTrader: (11)

Why not legal??

chesterfield

"113 casting # corvette heads"

Raised D port heads angle plug, right? Might need new headers, not sure.

F-Body Demon

iTrader: (1)

I just installed a set of ZZ4 Heads on my L98, heres what I have to say.

When GM first made the casting they did not have the D port exhaust. So watch out for that, you would be buying an aluminum L98 head...period. ZERO gain. In fact to go along with what 57kid was saying you would LOOSE POWER.

After a couple years they switched to the D port, now I was able to use my stock exhaust manifolds on my heads. The dimensions of the port were very close and more than acceptable for me. So you shouldnt have a problem with those "Exotic" exhaust ports. Tell you the truth I noticed a nice difference in my exhaust tone as well as a very slight lope that was not there before.

Something most people havnt added up yet is that GM never stopped casting the 113 heads. They are the current production piece for the ZZ4 (as aformetioned). HOWEVER! GM did not leave them stock. There was work done to the ports to help produce flow. I have read as much as 245cfm at .500 lift on the intake side and just over 200cfm at .500 lift exhaust. Meaning your normal ZZ4 heads are good for just shy of 500hp not to mention the (correct me if im wrong) 160cc intake runner meaning TORQUE TORQUE TORQUE. Your 305 would be a firebreather.

Now the problem I did have was the center two bolt holes did not align properly with my factory intake. I had to grind 7mm off the bottom side and 11mm off the top side in towards the EGR from the factory bolt hole to get them to fit.

Other than that they are GREAT heads.

chesterfield

This is something I've always been curious about. Back when GM offered the 350 HO Conversion kit with the ZZ4, part of the required parts were exhaust manifolds 14094063 and 14094064 (which I believe are what are found on 350 TPI 3rdgens). But the kit says you even need these manifolds for an L69 conversion which got me wondering if the TPI manifolds are designed to accommodate both Dports and standard. Just wondering.
I don't know about the original poster's headers, but some companies list different headers for D port.

FlippindaBird

iTrader: (10)

whats the difference between these and the iron 5.7L iroc heads, i thought they were the same except different metal

five7kid

iTrader: (14)

As stated, the later versions had D-shaped exhaust ports. D-ports are a slight improvement over the typical round ports.

And the noted chamber size difference.

anesthes

iTrader: (12)

Yeah but that would be 128 castings, not 113.

The loss in power would be from the thermal properties, and compression ratio change if the chambers are bigger. The flow is about the same, infact a hair better on the intake side. A hair worse than iron L98s on the exhaust side, believe it or not.


I don't agree with anything said above. Especially the 500hp thing, and the thought that a 160cc runner would be good.



The 113s are ok production heads. If anyone is building a car, and especially anything even remotely near 500hp they would have to be retarded to even consider 113 heads. Heck, just from going to a AFR 195 from a ZZ4 head has shown upwards of 70hp on the dyno.

-- Joe

Kevin91Z

iTrader: (1)

They dont have the EGR passage in those heads like regular heads do. In order to make the EGR work in an f-body, you need the Corvette-style EGR setup, with a tube coming off the headers into the port on the back of the Corvette or aftermarket intake manifold.

I've posted pictures of my old setup and the rules for Corvette heads several times in the TPI forum. and you shall see.

F-Body Demon

iTrader: (1)

My quote of a 500hp range comes from the calculation of intake port airflow and its relation to overall horsepower. A 245 cfm intake port reguardless of port size is still a 245 cfm intake port. Using Hot Rod Magazines formula for calculating horse power via headflow you simply multiply the CFM at maximum camshaft lift multiplied by 2.16. So lets see 245 times 2.16 equals 529.2. However we all know darned good and well that you, me or anybody is not going to be able to extract that amount of power from those heads simply because it would require a perfectly tuned setup from air filter to tailpipe.

So when I said 500hp capable I ment it, but I did not say 500 whp capable. Heck I didnt even say 500 crank hp with accessories. I mean 500 hp in its most basic of terms. At the crank with no parasitic draw.

Now moving into what I said about torque. A 235cc intake port that flows 245 cfm will not make power where a 160cc intake port with the same flow will. Right? Thats why we dont buy 235cc intake port heads for street cars.

Not trying to get into an arguement. I just dont like being called "Retarded".

anesthes

iTrader: (12)

That is a very over-simplified calculation that doesn't meet real world, honestly.

I intentionally ignored the 245 cfm comment because it's out of this world. While TPIS and other vendors may sell a ported 113 head that flows 245 cfm, here are the REAL numbers from Graham Hanson.:

Lift Intake CFM Exhaust CFM E/I % Velocity
.100 58 50 86% 95
.200 121 97 80% 99
.300 158 122 77% 87
.400 188 142 75% 101
.500 196 156 79% 106
.600 198 160 81% 107


So you can see the flow ratings at 500-600 lift are still under 200cfm, which is about 30cfm less than a stock vortec port.

Yes, but you don't understand why which is why I decided to add the above table including velocity numbers.

Ultimately, to make a car go fast you need port flow. CFM. However to build torque, and make the car go fast under 5,000 RPM you need velocity or it will be a stone on the street. As you suggested, typically a smaller runner will have better velocity numbers than a larger runner - but there is more to it.

The max velocity on the 113 heads is 106, vs 137 on the Iron vortec heads for example, yet the Vortec heads have a 170cc runner vs the 158cc runner on the 113 aluminum heads. So in this case, the BIGGER head both flows more and has better velocity numbers.

Now let's talk about a real 500hp combination, that is streetable. It won't include the 113 head because as I shown above, it doesn't flow enough nor does it have the port velocity to make a fun street car. It will starve on a larger engine because of the flow, and has a theoretical potential of maybe 375hp naturally aspirated.

Let's look at an AFR 180 head (current production). Port flow of 264cfm, with a velocity of 137. The flow exceeds what you thought the 113 head could do, and the velocity numbers are still way high and the head will perform great on the street. It can support 500hp naturally aspirated on a small block 350 with around 10:1 compression.

The next logical choice would be the AFR 195 head, which flows 278 CFM, with velocity around 127/130. This is the ideal choice for 383 + 400 cubic inch street engines, and can support 600hp.


I didn't call you retarded. I said if someone was going to use 113 heads in a performance build they were retarded.. There is too many decent heads out there for short money to waste time and energy on a crap head. You'll spend upwards of $1200 porting 113s to flow something near what a version 1 AFR 180 flows (not the one mentioned above) and still won't be there because the cross sectional area of the head cannot be improved because the casting is so thin.


-- Joe

RPOL98

with the chambers on the '113 head being 58cc, and everybody else's aftermarket head's chamber is around 64cc and up (except Edelbrock's 60cc), how much, or "what", are you giving up by losing this combustion chamber volume for power/torque or performance?

seems to me that going from a 58cc head to 64cc incurs some kind of loss, although it might be compensated somewhat by the head's air flow potential.

obviously the aftermarket head can be milled but that drives up the cost and then raises the intake manifold gasket sealing issue.

it's just been a nagging question rattling round in my head.

thanks.

anesthes

iTrader: (12)

Well, unless you have a C4 you are not going from 58cc to 64cc. (ok, maybe if you have a 305, but who builds those).

Most production heads are either 64cc, or 70 something cc smoggers.

Most production cars run around 28 degrees total advance, so if going from 64cc iron to 64cc alum you would ramp your advance out to 36 or 38 degrees to compensate from the thermal losses.

Still, in a perfect world, I'd like to see an alum headed engine about 1 full point of compression higher than it's Iron counterpart. But when spending thousands and thousands to build an engine, I'm not going to worry about $150 to angle mill heads.

No intake sealing issues if the machine shop has a clue.


-- Joe

F-Body Demon

iTrader: (1)

https://www.thirdgen.org/forums/tech...num-vette.html

GM Worked the Heads. 243cfm. Im not sure if your just thinking im talking about 113s off a production Vette. Im talking ZZ4s.

Also I was reading about the velocity they calculated in those tests, and im not 100% certain I fully agree with the math. They just take the height and width of the port and divide it by the cubic inches of volume. So I see the vortecs having a natural advantage. Anybody backup their math? I want to believe haha.

anesthes

iTrader: (12)

GM didn't work anything. same heads. The poster, who posted the numbers on his heads, worked the heads:

https://www.thirdgen.org/forums/post...492-post5.html


And never came back to the thread to back up his data.

In fact, if you look at this post in the thread:

https://www.thirdgen.org/forums/post...810-post9.html

His numbers are questioned, with zero response from him.


ZZ4 heads are 113 heads, according to GM the only difference is the valve springs. Same casting, same head.



-- Joe