The question for guys who have put aluminum heads on their cars is was the performance gained or weight loss worth the green backs? I currently have some midly ported, big valve 290 heads and have heard that modern heads, with their improved port design, are worth any where from 40-60 HP on a Chevy big block. Since horsepower is measured and the pen and paper it is written on, has anyone just bolted on a set of aluminum heads, gone to the track, and seen a reduction in ET or increase in mph? Big block heads are a fairly big ticket item and I would like to hear from the experienced before I spend what little money I have. Thanks for the input
I have Edelbrock RPM Aluminum heads on My 454, with the intake and matched cam it is a reliable and powerful combo that has done me well. The heads it started with were 1976 Peanut port Truck units though so it should be expected. The biggest gain was the reduction in weight. Dart Iron Heads will get you nearly the same performance, but weigh a bit more for a lot less cash outlay. On other advantage with aluminum newer style heads is better Combustion chamber design coupled with aluminum alloy, allows for more compression with out detonation. My $.02
Yes they are worth it. Pretty much every aftermarket head is worth a good power increase over any stock head. I like the aluminum heads since they are easier to port, repairable, and give a nice weight reduction. They usually are only a few hundred more than the iron heads.
The money difference wasn't a factor for me, I'm not even sure there would have been a difference to be honest..... the main reason I went with aluminum is I wanted less weight. Iron or steel versions of my head would have flowed enough for what I'm doing, so performance wasn't a huge factor.
I don't run Big Blocks but I like 'em on my small block. I should be objective here, since i slid that mill in my old beatup pickup I haven't met a muscle car dude in the metro that liked 'em. Ah hell maybe its me they don't like.
The aftermarket heads get thier benifit from better designed combustion chambers, runners, & possibly valve size. Aluminum is a greater conductor of heat than iron. Heat is energy. This parasitic loss of heat (energy) must be compensated for, or you could actually loose some power. To compensate, comp. ratio is increased 1 point.
George Does this mean I can change my 62 to 65cc Ford heads on my supercharged 302 to Trick flow 61cc aluminium heads and still run premium pump gas?
The smaller combustion chamber will increase compression, don't know how much. If the increase in C.R. is less than 1.0 points, then it should run on same octane. there is also the matter of weather (or not) the improved chamber design of the aftermarket heads aids in reducing the chance of detonation.Let's say you have aftermarket heads that are exactly identicle except for iron vs aluminum, the iron heads will make more power because of less heat loss.
I saw a recent notice Chevy had their alum. Vortec BB heads for $750. As soon as we get the peanut port BB swapped in, if it doesn't excite then they would be my choice.
how bitchin would it be if edelbrock or somebody started making heads for nailheads, early olds, etc? heck, i'd even pay the premium price to have aluminum heads with modern technology. too bad it's not too likely to happen any time soon.
Edelbrock makes aftermarket aluminum heads for Olds, Pontiac and even AMC. Yes, AMC. I have no idea how Vic jr makes money making heads for engines that were never terribly popular in the first place... So, who knows..you just might see early Olds, Nailhead or Y block sometime soon... -Abone.
Indy Cylinder Heads makes aluminum heads and crate engines for AMCs..... http://www.indyheads.com/id3.html
MOPARMORTUARY: Hey the compression loss is 2 points if all factors are equal exept head materials right? Huh? Compression ratio is not affected by the material of the cylinder head. Aluminum heads might have a higher knock tolerance due to superior heat transfer, but the compression ratio is determined by displacement of the cylinder and combustion space. I have a couple of small block Ford motors with aluminum heads. I know they aren't the cheapest way to build a motor. Good iron heads are available for less that will make horsepower. But, in terms of bang for the buck, I think they are worth the premium. Your results may vary.
I put Trik-Flow heads on my 289 (302 crank)...big difference going to the bigger valve. I dont really notice a difference in wieght on the road. I'd do it again.
I like you Beans...and I like Aluminum Heads. given the choice, I install them where ever I can...But I have different reasons. This, Friends and neighbors, is Texas, and all the Jokes and funny sayings about it are true (If I owned Texas and Hell, I would rent out Texas and live in Hell-Gen. Sherman, about the heat) They do a very good job of reducing weight and adding performance- and since you can run a touch more timing, you get better performance and the motor doesn't get any hotter. if you stick with a closer to stock timing, you can expect to run alot cooler than before, but we have cool running motors down to a science around here. That said, the only downfall to our latest engine build is...the heater never really gets HOT. it's more "lukewarm" but yeah. looneymum heads kick ass. and if you don't like how they look, paint 'em.
There is no horsepower in steel or aluminum. Repairability of aluminum heads and blocks along with the weight reduction are the main factors for their use in racing applications. The aluminum is also easier to work with. But if I had a good set of steel heads that were cheap, especially if they were for the street I would use 'em and put the bucks elsewhere.
And how many valve seats have ever fallen out of Cast Iron Heads? Aluminum may be cool but never as durable as Cast Iron.
well i have a pair of cast iron buick heads that some "expert" decided to put hardened seats in when it wasn't necessary. broke into a water jacket, one head now has a dime sized hole in the combustion chamber and no more hardened seats, as the heads were intended for a blown motor, they are now JUNK. aluminum heads could easily be fixed. there was as much money in these heads as a nice set of aluminum heads would have cost. and valve seats don't just fall out, something else has to happed, like being machined wrong, or severely overheated engine. as far as i'm concerned the pros of aluminum far outweigh the cons.
Valve seats don't just fall out? Tell that to Escort, Corvair or OHV single cylinder lawnmower engine owners. They have the worst problems in air cooled engines and the risk of having them fall out increases as you use larger valves. Far more problems in 2 valve per cylinder engines than 4 valve per cylinder engines. The cost of a fall out in a multi cylinder engine? If it falls out at high vacuum the pieces get sucked in the other cylinders and pinch the top ring lands. Can destroy the engine before you even thought of reaching for the keys
since aluminum and iron heads are going to make similar power when created equally, the big advantages that aluminum is going to have over iron is weight, and heat disapation. yes repairability is going to be in aluminum's favor also, but for the most part that is only an advantage for racers. as to which head to buy depends on your application. using aluminum heads on say a 351w being built for a 65-66 mustang that needs to handle as well as go straight is a good idea. but building a drag car for bracket racing, iron heads are likely the better deal.
not many of us are running air cooled engines in our hot rods, or escort engines for that matter. and i stand by what i said, failure is usually a result of some other factor, they don't just fall out for no good reason! find me a hot rod engine builder who says this is a big problem.
Ray did you ever find a replacement for those heads??? The only aluminum heads in my lifetime I ever dropped a seat in was an old set of Harley Pan heads that someone put hard seats in and the were machined wrong. I went with a bigger seat and remachined the heads myself that was in 1980, those seats are still in. Cool running is a probelm for sure. I run a pair of 11 inch fans on the Pusher, in the summer with load I have never got past 200 and I've only turned the second fan on once. 104 sitting at a light.
it hasn't really been a priority. the car is currently running a stock motor and the blower is collecting dust, hell the car is collecting dust too! one of these days i'm gonna put the blower on the stock motor and see what breaks, then build it properly. the hold up is the fact that i'm gonna run a huge intercooler, and need to relocate the radiator and rework the whole radiator support and grille area to make it all fit.
I am still a lover of Iron heads.From what I have seen if you take two engines built the same way and run one with iron and one with aluminum the iron head engine will built more power.After all heat is horse power. Aluminum is lighter and yes it can be repaired but at what costs? a iron head can take a pounding after a engine blows up, while a aluminum head will crack into a bunch of peices.then you have to get it welded,machined, valves seats cut after the head is welded, these cost can be up there,sometimes it can cost as high as the price as a new iron head!
Seats don't just fall out of heads. They do when installed by jackass automotive machinists who don't spend the time to do it right. Some stock inserts are actually cast into the head. For example a triumph motorcycle uses a "threaded" seat which the head is cast around. Usually most failures are because the seat insert is pressd into the head and a burr forms underneath the seat so it cannot fully seat. Then after a number of thermal cycles the seat falls out. While many times pressing the seat in may work, the better way is to put the head in an oven and heat it up and put the seat in liquid nitrogen and the seat will simply fall into the machined pocket and then expand as it warms up. No burrs. This is how it has been done on large industrial engines for years. Large NG engines have to use inserts because they are very hard on seats and even with tool steel (60 rockwell C) seats they still get valve seat recession.
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