I ended up taking them off, I had some other issues going on and had to get the car running right in a hurry, so it has the original heads back on it. I want to put the aluminum heads back on, but haven't got around to it yet. Lighter, cool better.
I have nothing against iron heads but many years ago I bought a pair of heads from a guy because he was a sort of neighbor and I thought they were a fair price, he said the guy he got them from (heard that before) told him they were "reconditioned", in short order they started fouling plugs due to sloppy guides, when I saw a sale on Edelbrock heads I decided to put the problem behind me, all it took was to write the check.
HMMMM so I have been racing drag and stock car for years from about 1979 . I have ground enough on factory 461, 2s< over the counter angle plugs and even a set of bowties . Angle cut , bigger valves , bigger studs , on and on and there is not Likely 25 HP from my wort heads I did to my best if put on the same engine. Now I can take a 15 year old set of used CNC ported RHS heads Pro elites I got used for $800 and they will make about 800 HP on the 410 engine they came off of and will make easly 600 on a good gas engine and will make over 500 on a pump gas engine . there going on a 383 build next and are over kill BUT I will expect 500HP with them on pump gas and big roller cam and it will be drivable. My best set of bow ties would give up 100 HP or more and my good 202 fuely heads with lots off quality work will not come close . A set of $600 bare ebay heads will get you likely 50 HP over the average fuely heads and you can run abiut 1 point of compression or about another 10 HP and better gas millage from the more compression . When things go bad and it all explodes the aluminum head can likley be fixed the $2000 set of cast hand ported no single replacement head available are likely junk. I and a buddy are building a pair of 383's one for his 1965 GMC truck with a stick. he was going to go with the Vortec heads he had done up last year to take higer cam lift and he had 2.02 valves , studs and guide plates as well he has about $850 in these heads he installed last summer on his 4x4 truck this truck ran great made about 390 HP as a 350 . WELL last night we tear down that engine and both heads are cracked and junk. No fixing them pull the valves and parts and scrap them . Hes going to likely buy the jegs aluminum heads now . There about $1000 he can choose the runner and chamber size to fit his flat tops . those heads on his cam should make 550 hp . And take 100 pounds off the engine . unless you need a certain nostalga look were are you going to buy a 50 HP gain better millage , able to run lower octane gas and loose weigth for the approximant $200 more these will be over the cast one that he had to throw away? He might step up to the AFR or Brodex as cast stuff thats even better for a few hundred more but he will meet his goals easy with the Jegs house brand likely cast in china heads , even the cheap AFR and Brodex heads are import casings now . my RHS heads were cast in Australia I'm told. Then there is the BBC chevy stuff were and cheap set of aluminum make a old set of Square ports look like crap as far as HP and you don't have to search for two years to find them. there are some good Cast iron after market heads being made still but there goig to have bolt holes on the end . I considered and se tof the fake aluminum fuely heads for my vette but its so not stock ill take the extra HP from the better options for less . The aluminum fuely heads look great a few post up and if I had a car that looked more stock id go that route and paint them . What's funny is in the early 90's if you had a set of aluminum SBC heads like Canfields on the street your were like a god and now your just some lazy shmo that picked up a catalog . Around 86 I had Brodix 10's on a 410" in 24oZ back then and was hot stuff . Today those heads might bring $600 if usable . Sometimes the new stuff is actually better even if its not what you want to see on a vintage era car . At least I'm not building a LS LOL Ill use my cast stuff and I have a bunch of it for my budget build 283, 307 , 283 and cheap driver 350's that might be on a old school rod .
Welp....prolly Hemi Heads.......BBF heads (AND cast arn intakes fer sure!!!)...348/409 heads...Aluminum would be the way to go BECAUSE OF the weight savings. I was just think'in SBF stuff. (Everybody and his neighbor makes Al Shivelay heads fer couple hundred bucks a set so yes that is a no brainger) I guess the proper answer is......it depends ! 6sally6
According to an article I read some time back the heat transfer is enough that you should/must compensate by upping your C/R by one point to break even.
They're about 60 pounds bare. For reference a 455 Buick head is 56 pounds bare, small block Chevy is apparently 44 lbs, and a big block Chevy is somewhere in the realm of the hemi, maybe a little more (couldn't find an exact number for a bare head). So not hugely heavier than others, maybe the valvetrain adds a bit more weight. I can tell you that lifting a 455 Buick head into a narrow 1940's engine bay of a fendered vehicle sucks. It sucks even more if you have the cast iron manifold attached. When it's a big block, they're all heavy.
Bare or assembled? The only figure I found is 75 pounds, but that seemed to be with valves and springs.
The article said something to the effect "the aluminum allows for (around) one more compression point when iron heads might be experiencing detonation in street driving".
when they're that heavy, it doesn't really matter! but I could weigh a couple, I have a bare head and a couple assembled
https://www.hotrod.com/how-to/ccrp-0602-iron-versus-aluminum-cylinder-heads-test/ Here is a back to back test of nearly identical same brand castings one aluminum one iron and there as no real difference in HP at any temp . What the test did not test for was how much more compression could each head run at with out detonation or even get into how much more cam timing could be ran . What's is really being missed is there best flowing options out there are going to be aluminum at least for a SBC and there going to make more power and there is no cast otion to equal it . that said there are some really good Cast performance heads. then there is the weight savings . loose a 75 pounds on a light car and it matters . I don't think its a myth that aluminum heads can be ran at a higher compression ration on pump gas were it matters . While not apples to apples I have had 64cc heads both cast and aluminum on a 12-1 327 and I could run pump gas ( barely with the aluminum and do so with what id call full timing now were the combustion chambers different and a factor ( sure id imagine ) but I cc'c both heads and they were with on a haf cc of each other and the iron heads I could ot really drive even at 30 degrees advance or less. I wish they had ran that test on a 12 to one engine or more were timing had to be retarded to stop pre ignition. Fact is if the iron heads run at full timing vs a identical set in aluminum is not going to really matter. Its what you can do better / more compression with the aluminum heads on say a build were you choose what compression . My opinion
Question for everyone out there, do you mark any parts that are taken in to be assembled. Just curious because a few years back a buddy of mine bought parts only to find out later that they were not installed on his build. I told him he should of doubled checked, needless to say he never did business with the guy again. I know some parts you can visually see and confirm but there are others that might be harder to mark or detect for example like valve springs, retainers etc. As everyone knows this hobby can get expensive, even with a basic build the dollars add up quick. I know it would of been disappointing to find out the parts I bought were not used.
I've been assembling my heads lately, so that's not an issue. If you can't trust your machine shop not to steal your parts, maybe you need to move, or something.
Not sure about all brands or makes, but I've seen plenty of cracked cast iron SBC heads that happened from getting way too hot. Can't say I've ever heard of any aluminum SBC heads ever cracking? The key is not too get either way too hot. As for marking parts, I've never done so. But I've been using the same father-son machine shop for engine work since 1974, and if they did me wrong I wouldn't have used them this long!
If an aluminum heads gets to hot it can wreck the temper. Think I saw a warning not to hot tank them on the Brodix or similar site. Later SBC heads that are lighter castings are more crack prone. Just had a cracked Vortec head on a engine I tore down hoping the heads were good Anything cast overheated enough can crack . Thing is aluminum heads can often be fixed even really messed up ones. I fixed a set of Brownfield heads back around 1994 that had two chambers and there valve seat area missing chunks. Got them almost free from a sprint car buddy. Cleaned them good and started weldding any were that was missing an area or had damage cut the chamber back in with a die grinder and then machined in a place for news seats then surfaced them . Worked fine. My time was free then . Today heads are cheap and common today but then they were a big deal . Considering they were good for about 50 HP over my 461 heads it was a bargain.
The Dart SHP heads I put on my '39 Chev 355 SBC are only the 2nd pair of aluminum SBC heads I've used. The first pair I bought almost new off a Craigslist ad locally for $500 and they were fully assembled. Put them on my Austin gasser and within a very short time I had issues. I narrowed it down to the heads, and took them to a local machine shop to be checked. He told me the guides were junk, and valve stems were too small for the guides. He also said valve stems were an oddball length and would require a special order to replace! I ended up trading them to him for a pair of rebuilt 461 camel hump heads instead. I'd never buy assembled Chinese heads again! I also got my Dart SHP heads also used from a local swap meet complete with roller rockers for $700. Seller said he was switching to the biggest Dart heads made for SBC, so I got a great deal. They've been excellent heads on my 1990 roller motor and made 430 HP and 419 torque on the dyno when I had the engine run before putting it in my build. It's around 10:1 c.r. so runs great on pump gas.
I'm going to a set of speedway aluminum double humps for a variety of reasons. How does the expansion of the aluminum affect how you set the cold lash? The engine is a stock spec 327 ,with the exception of getting a small crower solid lifter flat tappet cam at the same time.
I run Edelbrock aluminum heads on the coupe, pricy ? Yes ,but as the old saying goes, you get what you pay for . I would never ever buy cheap ass heads new or used.
The Jalopy Journal
