Got a set of aluminum (double hump) heads from a L79 365HP? 327

Casting 3782461
62.076cc
2.02/1.94 valves with 3 angle valve job.

They were free. They are recently rebuilt. Are these worth messing with on a 355. Will they flow well enough on a carbed engine to make decent numbers or should I ditch them and look for something else? All input is appreciated

 

Get a clue. There's a reason why you got them for free.

They are not aluminum. Painted aluminum color maybe, but not cast of aluminum. Check them with a magnet.

They probably didn't fit their previous owner's car, and won't fit your car either, if you have a 3rd gen. Plus, they lack the adaptations for the watered-down cat pee they sell these days as gasoline.

Keep looking. Put those in Hemmings Motor News as "Vette" heads, for a 64-67 327; some one of those guys will come ****** them up sooner or later, for too much money hopefully, like they often do.

Incidentally, while the L79 was a decent enough running motor in its day, the HP "rating" is a total joke.

 

OK. Got a clue now, I guess. A simple they aren't aluminum, old technology = less flow, not what you want to use, there are better choices out there, would have sufficed.

Why, because I ask a "dumb" question, must you doubt that I even have one of the hundreds of thousands of 3rd generation F-body cars that were built?

And I guess the numbers on the heads were machined down and then rebuilt to look like they were cast from the material which the head is cast just to trick me into posting this question. They would fit my engine since they are sbc heads.

Thanks for your opinion, though. I did get something useful from it. I was wrong about them being aluminum as a magnet does stick to them.

Maybe I'll get lucky and sell them for too much money. I wish I had more stuff that may be useless to me, but had the potential to be worth lots o' moola.

 

RB83L69 is right theres a reason you got em for free. Most likely there either cracked or someone did a crappy valve job. I belive when he was talking about fit he ment the lack of accessory bolt holes meaning you have to get diffrent brackets(read more $$$$) to mount the alt. power steering and a/c. Their decent heads but you should be able to sell em for $200 or more cause most people especially the older guys think their gold.

 

10-4. Wasn't thinking about accessories as I new I could replace brackets. Will get them checked out and see if they are cracked or anyting bad.

 

Yes, if there truly is nothing wrong with them (definately have them tested), they will work great on a 355. You don't have to invest a bunch of money in a set of aftermarket heads to get respectable performance from a SBC. It isn't hard to get 1 HP per cubic inch, using factory heads. I have some '993 castings on my engine, which are basically smog heads. The 1.94/1.5 valves were replaced with 2.02/1.6's, they are otherwise stock. See sig for times. My car should be in the twelves now (changed the timing advance from 8*-12*).

 

People who have F-body cars post generic questions about their 71 pickup truck that they also have, so when we tell them they won't fit, they then say "they're going in my 66 Chevy 2 drag car" or whatever. Which is why I qualified my answer.

The holes that they lack are virtually impossible to fake or substitute for. People have been trying since 1969 to come up with a working scheme; no one, myself included, has managed to make anything that would hold an alternator using stock brackets and not sling the belt. There are a couple of complete bracket assemblies available from aftermarket vendors, but they're $$$$$.

That's the main reason you got them for free; they don't fit any cars made in the last 30 or more years.

The fellow with 993 heads has the accessory bolt holes. Those heads, while crap, will at least bolt up.

441s flow pretty good, for their day. But there's alot more to choosing heads than just that. Combustion chamber design is a big factor. Those older heads lack the "squish" area over on the spark plug side; they're just straight bathtub chamber heads. That change allows the engine to run on at least 5 points lower octane fuel than without it.

They also lack hardened seats. The lead compound they used to put in gasoline was a terific lubricant, and it prevented rapid valve seat wear; using untreated heads with modern gas, the valves will dig right through the soft cast iron and cut a tunnel down into the bowl.

So, it really doesn't matter what valves somebody put in htem, they're a terrible choice for your car. But they're the factory heads for those old Vettes among other things, so you can sell them to somebody needing them for a "numbers matching" car, which is what I'd do if I had them; then I'd get something better.

If you want good double-hump heads, the ones to get are the 186, 041, or 492 castings.

Here's a set of 186s:

 

I've heard of that alot but I've never seen it happen. Out of all the motors my pop, brother and I built we used heads on a couple of em without hardened exhaust seats and never had a problem. The guy at my local machine shop can't cut a valve seat to seal for nothing and they have a brand new Serdi 3.0 seat & guide. Poor machining might attribute to the leaded gas and harden seat deal.

 

Umm.... I don't think so.

It happens, even to heads that have never been machined. I've seen valves that have dug themselves 1/8" into the head. Your typical "I'm planning to build one" or even "I put them on last week, I don't have it running right yet so I haven't driven it yet, it's OK so far" type of guy won't notice it; but those of us who build motors that are reliable and then can actually use them for years on end like one would a new motor, know better.

Go put a bunch of miles on an engine built with those old heads; it'll happen to them, guaranteed. That's whay they started induction-hardening the seats in about 69. The old heads wouldn't even reliably make it through the 12,000 mile warranty of the day, sometimes. People would put "white gas" in their cars for whatever reason, and that would be the end of the heads. I seem to recall at least one of the car mfrs ending up stating that the use of that type of fuel voided the warranty, for that reason

Modern gasoline does have something in it to help lube the valve seats, but it's nowhere near as effective as the powdered lead & lead oxide mixture that used to coat everything inside an engine back in those days.

Of course, you can put replacement seats in heads, that are much harder even than stock induction-hardened cast-iron; but why would anybody in his right mind do that to a set of old heads that don't fit in the first place?

 

I found a set of old style heads oin ebay a while ago and after these great guys like RB83L69 gave me all the info I needed NOT to buy those heads... These guys know their stuff... Yeah they're cheaper now but It will save you $$$ and hassles in the long run to sell them while u can and get something better...I am leaving the stock truck heads on my motor until I can afford some Sportsman IIs..

 

No, mine don't have the accessory bolt holes. I used the old V-belt setup (junk yard parts, very inexpensive). Also, I wouldn't consider them "crap". From what I've read, they flow comparable numbers to the 492 casting thay you suggest. The reason 492's are considered better for performance is the smaller combustion chamber size (increased compression).

 

I find it very hard to believe that those heads have no accessory bolt holes..... they are a 70s production part, long after all cars began to require bolt holes. The same casting is in use to this day, as the "Hecho En Mexico" castings on the Goodwrench 350

Where is the alternator in your car?

 

The alternator is now located on the passenger side. The heads have 1 bolt hole on the passenger side and 3 on the drivers side. I don't remember the bolt pattern of the factory (LG4) heads, just that my factory serpentine setup wouldn't work.

 

by "Poor machining might attribute to the leaded gas and harden seat deal" I mean some people might get a sucky valve job done and then think because their running unleaded gas thats why their valves are receeded in the head or don't seal. And I'm not "Your typical "I'm planning to build one" or even "I put them on last week, I don't have it running right yet so I haven't driven it yet, it's OK so far" type of guy" I've been rebuilding engines for the past 9 or 10 years and hell my dad has been doing it for the past 35 years. and the only engine out of the 12 or so we've built to screw up was a target master 350 that my bro cheaped out on by not getting the crank ground and the rods recondition. it wiped out the #1 & #2 rod journal, it ground about a 1/16th" right off the crank.

 

Those are accessory bolt holes. The old heads have no bolt holes.

 

gotcha, misundestood original post

 

i bought a 350 for 1200 bucks canadian with everything but a carb and intake. it had a fresh rebuild and had a set of 461 heads on it. since i could not afford a better, ie an aftermarket set of heads, i used the heads that were on the motor. i used some brackets from hedman headers that i got at the local speed shop and modified them some to allow me to use such luxury items as the power steering pump and the alternator. hehehe.

anyway, i havent had any problems with belt throwing and what not on my car (84 TA). while along way from being fast, it runs 13.87 with 2.3 60fts. this is with the stock open rearend and 3.23s (4.10s and a posi are sitting in my garage). still slow, but i am working on changing that.

anyway, lord knows i have next to no knowledge compared to RB, cause he is one the smartest guys on the board, but i havent had any problems in the first year since the swap. granted its only a been a year, but still its a good sign. anyway, i just thought i would mention that i have had some success with these heads. i would rather something better and newer, but this is all i have to work with now. accessory bolt holes sure would be nice, but sometimes you just have to make due with what you have. i have alot more money now, so maybe a can get some better heads, but new performance heads are worth more than my car is.

sorry, i dont have any pics of my accessory setup, but i dont own a digital camera or scanner. anyway, in the end, i would still take RB's advice and NOT use these heads if at all possible. there is better stuff out there.

 

Well, the heads checked out fine. Took them to a local shop, no cracks or other problems. If, for nothing more than a test, I'm going to give them a shot. The worst that could happen is they suck, remember they were free, and I replace them. So here goes the next step.

Have a 350 2 bolt block. I know 4 bolt will handle more power, but 2 bolt is what I have. Plan on punching it out .040 by a shop that will align bore the cylinders. Gonna have the mains align honed. Use studs on for the main caps. Go with quality main and rod bearings. Planning on keeping the stock rods and having the whole rotating assembly, with new pistons, balanced. Will not be using any power adders. Am not looking for a world beater just a daily driver with some punch. Will be setting a dual plane intake on the heads. Will have the heads and intake port matched. Will be using 1 5/8 primary headers. The car will be pushed by a 2.77 posi, for now. I have a TH350 tranny in the car now, but will be making the change to t-5 or t-56 if I can convice the wife 1 more gear is worth twice the dollars, when the TH350 kicks the bucket.

So am I missing anything major besides the cam selection? Remembering this will be a, mild, daily driven street motor am I on the right track?

Recommendations wanted.