First time swapping edelbrock aluminum for 915 cast iron heads.

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To OP: Put them on. You'll notice an improvement and be happy. The rest is overthinking.

Edit - AJ - I avoid your posts due to length and amount of convolution....lol.
 
I get where your coming from AJ and agree, you know your chit. But you seem to be in a similar position that I am in over in here in UK, Start talking Tech (nowhere near as complex as you do), and most, not all, look at you with a blank expression, walk off or change the subject, frustrating to me as an ex racer, the money wasted on incompatible parts that I can see on some race cars is staggering, and sadly it seems to be more prevalent with the mopar guys. I've just learned to forget it all and just talk about how nice there car is lol.....there are a few exceptions, only 2 currently, 1 runs 8.80's in a '68 Cuda and the other 9.30's in a '64 Fury NA. There is 1 example I could give that is mind boggling but I won't bore you with all the details as is off topic anyways.
 
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You know, I think there must be quite a few UK-ers out there looking for the truth. I've gotten a few PMs over he past while. I guess it's summer over there now, and guys are planning their winter projects. I hear things are crazy expensive over where you are, even tho you're just a short hop from the west coast of USA. For me the delivered cost of anything from the US is about 50% higher than it would be to a US resident, so that makes things pricey for me as well. But I get free shipping to the border in a lot of cases, and I'm less than an hour from the US shipping depot........by car,lol.

Now I got a question for you
You guys have pure RON gas in grades of 95 and 98 over there.....is that right? Do you know,for a fact,how that equates to USA gas?

I have read that our gas is rated (RON+MON)/2....I get that.
I have read that the MON test is a more stringent test, and lowers the RON rating by 8 to 12 points, some sources quote just 10 points.I get that too.
What I cannot find, is that it's the same gas, just tested differently, and so they just average the numbers, here in America, thus reducing the Anti-Knock Index.
If that is correct, that it's just a test; then 95RON goes to 85MON, and when the two are averaged WE get 90 octane (R+M)/2 also known as AKI... but it's the exact same gas!
Can you speak to that?

The real question of course is : "how much cylinder pressure can a street-guy in NZ safely run, with iron heads ,and/or with alloy heads: and under what circumstances; and with what grade of NZ gas,lol."
And of course, what pressure is likely to cause detonation?, for guys like me that want to explore the limits, and are willing to backpedal,as may be required.
I need to be as sure as is possible.

So far as I've been able to figure out:
your 98RON is (98+88)/2 = 93AKI(US), and
your 95RON is (95+85)/2 = 90AKI(US)
Plus/minus about 1 , in each AKI-grade.
 
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Yes we have unleaded 95RON and Super 98RON, we also have BP ultimate/V-power and others which are 99>100RON I believe. Not too up on fuel tech tbh so cannot answer your question with any authority, I just put SU in my Focus and thats it these days.

Its still winter here and most of the guys here are busy with there projects getting ready for the season opener on 30th March "Festival of Power" at SPR. I haven't been involved in racing a car for over 20yrs now and just attend to watch and chat with people I knew who are still running today as well as the new guys. Still have an interest and learnt a lot over the past 4yrs since I got back into a bit from here and Moparts, but tbh it ain't the same as it was back then, we had to work and think to make HP from factory stuff, now you just pick the phone up and order your 800+hp motor and go quick, or in some cases not.

The issue with some UK-ers as you put it is most won't ask the people they should be asking, and that doesn't mean me, I'm no-one special, they just seem to make wrong decisions or talk to the wrong people, I don't know, perhaps its the internet and just looking a the glossy ads, or the English trait....reserved, ....to me, if you wanna learn you go speak to someone thats doing it or has done it and ask just like I did when I started, but back then people talked more. One thing I will never forget though was back in 1985 when a Funny car driver came over to me and asked what I've got inside my 340 after firing it up to get it off the trailer, they just didn't do things like that to us sportsman guys...anyway enough waffling from me.
 
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AJ/Forms
I do appreciate your and everyone else’s input. It has been invaluable on this website and without it I wouldn’t feel confident enough to tackle many of my jobs I have accomplished. I have to admit you are extremely knowledgeable in the compatibility of engine parts to create a superior performing combination. The problem for me is much of what you were saying was beyond my general knowledge and it made me second guess my performance part choices. But after I thought more about what you said I think I have come to understand a bit more. If the compression ratio is too low then you are leaving a lot of performance on the table and you also want your cam to develop maximal torque lower in the rpm power curve to be more responsive on the street where you may not easily be able to get above 6000rpm’s. Also as the compression goes up the cylinder pressure seems to rise if the chamber stays the same size. Higher cylinder pressure more powerful explosion greater power produced. I think I get it. But for me I have a couple factors to consider when talking compression ratio. I know there has to be a point where the compression is too high in an aluminum head to be practical to run on 92 or 93 octane. I don’t want pre-detonation and can’t afford to run a mix of race gas. Also even if the engine with 10.2 compression with the eddy heads leaves power on the table as long as I get a noticeable bump as compared to 9.8 to 1 iron heads I’m sure I’ll be happy. I would be unsure if I tried to run my motor with the aluminum eddy’s At 11.0 or higher compression. I think I would be setting myself up for problems. Especially with the ethanol they run in the gas in CT. Also I think there is more leeway in a slightly more radical cam when you run a 4 speed on the street vs an auto trans. What are your thoughts?
Carl
 
I’m reaching out again for some advice. Well I’ve broken loose and removed all the lower head bolts from where the head bolts to the block just above the plugs. I think the easiest way to remove the remainder of the head bolts which are inside the head below the rockers is to remove the rockers. Would that be correct? Now looking at the shaft mounted roller rockers can I remove the rockers all at the same time by removing the entire shaft then just drop the shaft on top of the new eddy’s. I’ll take the pushrods and make sure to match up each pushrod in the same place on the new heads so they work with the same rocker. Can I get away with just oiling up the metal to metal surfaces where the pushrods touch the rockers and rockers touch the valves on the new Eddy’s or do I have to buy break-in lube? I have included some pics so I can reference them. In the one closeup you can see the end of the shaft with the hold down bolt and what looks like an Allan key running in through the side. What do I do first to remove the shaft? Than can I loosen the hold down bolts along the shaft and then lift it off? I’ll be sure to liberally oil up all the metal contact points. Than when I drop it on the new Eddy’s I can set the preload and make sure the clearances are correct? To set preload when rocker is in place first wiggle the rocker lightly and tighten down the Allen key until there is no more play. Then turn the Allan key one full turn tighter hold in place and tighten the lock nut? That is called setting the preload correct? Then do I also want to put a feeler guage in between the roller and top of valve? If so what should be the clearance or should there be none because it should of been taken out when I set preload? Can I use a pry bar to separate the head from the block and where to pry from? When I put the new aluminum heads onto the block both surfaces should be spotless and I shouldnt need any gasket sealer just my cometic gaskets right? Lastly what are the general torque specs:
Head bolts?
Rocker shaft bolts
Rocker hold down bolts?
Thank you ahead of time as always.
Carl

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