68plymouth383
Senior Member
I've been using a comp cam 260 high energy in my truck since 2003. I've also been using a comp cam 268 high energy in my 68 fury with a 440 since 2012. There great cams in my opinion.
Need Big block advice!
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moper
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Iron is well known to make more measurable power - because heat=power and iron keeps that heat in the chamber rather than wicking it away faster. Coatings have come about for that very reason. Aluminum in and of itself does not make anything detonate less. It allows a builder to make other choices that provide value and benefit. In terms of racing - it's lighter which is worth a lot more than the few ponies iron might give. Any serious inquiry into having an iron block lightened to fit a class and you'll see what it's worth. Aluminum is also easier to port, and easilly repairable which also is a more important reason for a race application. So why use aluminum then? The chambers. Oldguy knows it but for some reason likes to keep the older iron around...lol. I like nostalgia but common sense usually wins out when I'm spec'ing parts for an engine. The aluminum heads all have a closed chamber (open chamber options aside). It's not a great closed chamber on most of the cheaper ones, but it is closed. Which allows me as the builder to take advantage of the properties of quench. Some may dispute those. The benfits are engineering fact but like all things some don't like change or think they know better. As this is my opinion anyway and unless I'm building for you, it doesn't affect me at all. My only request would be to show me any production car or truck gasoline powered engine that does not make use of it. So if you are repairing an engine - aluminum may not be the right choice as it's money with little more real performance benefit beyond what a good valve job might deliver. But if you have a clean slate - and there's not a rule that prohibits them I'd call it foolish not to use them.
In terms of dollars and cents - if you could run 87 octane fuel over the life of the engine vs 91 octane - would that $.40/gallon make sense? Over 20K miles (four years in most of the "summer driver" cars around me) that's $1866 in savings and you get port flow that matches a medium level of professional porting on iron. You also get a lot of weight off the front tires. So you're not spending fuel accelerating it.
Again - just my opinion.
In terms of dollars and cents - if you could run 87 octane fuel over the life of the engine vs 91 octane - would that $.40/gallon make sense? Over 20K miles (four years in most of the "summer driver" cars around me) that's $1866 in savings and you get port flow that matches a medium level of professional porting on iron. You also get a lot of weight off the front tires. So you're not spending fuel accelerating it.
Again - just my opinion.
monaco75
Senior Member
This is pretty much exactly what I did with my 440. I went with the comp xe256. However I'm wondering if I went too small... I wont know for a long time as the car isn't ready for it..
The 256 gets a lot of great reviews for small blocks, but not a whole lot out there for big blocks.
heyoldguy
Member
Iron is assumed to make more power as people have repeated the same story for 40 years without any dyno tests (that I have found) to confirm it. Show me the test where iron gives more power. I have regularly posted the only direct tests I have been able to find and they indicate the opposite.
As for me and iron heads, I keep running iron heads just to rub the noses of aluminum head runners in the iron powder, not power (from our porting). Sure, we can make the aluminum heads run better.
Dyno test confirmation. Went to a dyno competition running a 451 stroker. All engines were required the use the Edelbrock 84cc RPM cylinder head. Under the same rules the other 451 engines in the contest made 585 HP. Our 451 engine using 452 iron heads made 621 HP before the contest. When asked what we would make with the Edelbrock heads we told them 100 HP more than the others 451 engines. That evening, at a dinner we were not at, the joke of the evening was the LaRoys thought they were going to make that much power from a 451 with RPM heads.........it was impossible. The next day they were right, we didn't make 100 HP more, it was 138 more horsepower. We put down 723 horsepower that day. The following day it took a 500ci stroker to beat us by 1 HP.
I try to help people who say they are going to run iron heads to get the best they can out of them. I always recommend the aluminum replacements, if asked and if it is in the budget, as they are a better designed head. I'm not one to tell the guy, who is running iron heads, how he needs to switch to aluminum.
We are free to make our own choices and iron isn't a bad one. I prefer aluminum.
commando1
Old Man with a Hat
Jeeze, Old guy. I understand the point you're trying to get across but here we're talking about guys doing a "rebuild", not building a race engine. And these rebuilds are for barges doing street duty.
Is there ANY practical common sense around here?
This is the equivalent of Nancy Pelosi wearing Victoria Secret underwear. Nobody's going to see it and it's never going to enhance anything.
Is there ANY practical common sense around here?
This is the equivalent of Nancy Pelosi wearing Victoria Secret underwear. Nobody's going to see it and it's never going to enhance anything.
I done care if we strayed a little (that's never happened here before), I love this stuff!
commando1
Old Man with a Hat
You liked that about Nancy Pelosi's underwear, eh?
You got me.
bajajoaquin
Senior Member
Huh? He says he wants to make more power on a budget. You're the one who is saying he just wants a rebuild.
So I come back to my position that the 440Source heads (and Eddy heads, for that matter) are a pretty good way to go. The only person here who has actual numbers suggests that you'll pick up between 30 and 60 hp if you swap them on. Considering that they're only $400-$600 more than stock rebuild, on a rebuild that's already going to cost you $3k, that's probably a pretty good bang for your buck.
70bigblockdodge
Old Man with a Hat
I will let you know what my iron heads run hopefully by June. I own them they are ancient and they are going back on.
72Fury
Senior Member
My estimate yesterday was almost $900 not including valves & springs. Aluminum heads here I come.
commando1
Old Man with a Hat
Now that makes sense. That's too much money.
72Fury
Senior Member
The estimate was $675 & then another $200 for replacing the seats. He recommended changing them even if I got a set of 452 heads, as he has seen them (the seats) come off.
I plan on using the stock hp intake & air cleaner etc for a stock look. Alum heads with a cast intake just *feels* weird though. For the moment, I need a new harmonic balancer, if anyone has any suggestions.
I plan on using the stock hp intake & air cleaner etc for a stock look. Alum heads with a cast intake just *feels* weird though. For the moment, I need a new harmonic balancer, if anyone has any suggestions.
That's what I was telling you upthread
70bigblockdodge
Old Man with a Hat
A Mopar dual plane aluminum intake is just like the late model cast iron intake. Jegs has a SFI rated one for neutral balance for $147, they are tested, new and not $400
68plymouth383
Senior Member
If you've used this machine shop before, and trust there giving you an honest price great.... If not i would get a second opinion.....
72Fury
Senior Member
Yes, I trust him. The machine shop has been in the same building since 1933. Third gen machinist. One man show. He did the work on my Mini, which was pricey as well, but excellent. His recommendation was aluminum. Same thing he did to his bb 69 Camaro.
70bigblockdodge
Old Man with a Hat
Trust is definatly worth a couple extra bucks. Mopar guy that did machine work around here passed away last year, but I've got a couple of options
heyoldguy
Member
Please, just for me. Ask the machinist how the cast-into-the-head induction hardened seats "came off"? I have yet to see this. Did they break off or does he mean 'ground out'?
In his defense, yes, for hard or extended service, it is a good idea to use hard seat inserts.
72Fury
Senior Member
I took it as they came off & destroyed the engine. He told me they can become loose. He works on a big variety of stuff, from heavy equipment to Porsches/imports to muscle cars, so in all fairness his reference might not be to a 452 head but something else. Not trying to scare anyone. I'll ask anyways. He did recommend the alum heads, even though it would cost him a sale, in his own words.
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