I have a set of 3970126 heads off a track car, they have $500 dollars of porting/polishing/valve job/spring seats/springs/etc done to them, they now have 2.02/1.60 valves... I know what they have now, but I can't find anything on them stock except they were 1969-1974 heads... Any help?

 

They were 327 & 350 2-bbl heads from about 69 to 72. 70 or 72cc or thereabouts if memory serves.

Doesn't matter how much somebody wasted on them; they're not good for much.

 

They are 64 cc not 70-72, from what he told me. They were on a 380rwhp motor and swapped for aluminum, that has to be worth something, right?

 

No.

They were 327 & 350 2-bbl heads from the very late 60s and early 70s. 70 - 72cc if memory serves. I recall throwing away quite a few sets of em back then and replacing em with something decent; 186 usually, occasionally 041.

They ARE what they ARE. Romantic stories and "track" this and "swapped for aluminum" that doesn't change what they ARE.

Sounds like a relic from a day gone by when they were the "spec" head for some class at some track. That's one of the ways, in round-track racing especially, they (a)equalize the cars, and (b) control costs; is by requiring that some particular casting must be used. Some tracks will limit what you can do to them, some not. Doesn't make em any better of a casting.

If you got em for free, and you're just going to stick em on something, that's one thing... I wouldn't pay a dime for em though.

 

i can tell you they were made from wishes and dreams, but that doesnt make it true. theyre old outdated heads that the guy just offloaded to someone who didnt know better by using all those fancy words. newer heads will far out perform those heads with no extra work. like sofa said, if you got them free, use them till you get something better. if you paid for them, then you got ripped off.

never take someones word when buying something.do the research on it. people will tell you anything to get you to buy something.

 

I understand everything being said, just don't understand how if a head is crap standard and it's made to hold a certain lift, the lift is a lift, the chambers are chambers, and all.... It has been ported, everything is smooth as silk, the valves are 2.02/1.60 they are huge, what exactly makes them crap; other than being outdated?

If they are 76cc they will lower my compression, with stockers being 64cc

Other than those reasons, why are they so bad?

 

older heads were ment for leaded gas. meaning they dont have hardened exhaust valve seats. the older castings are also more prone to cracking\warping. youll loose hp from compression and from flow characteristics. theyll work if you can get them for free and have nothing else, but spending money on them is money that could be spent on newer heads that will outflow those heads even with all the work done to them out of the box.

you already have the heads so run them while you look for something better, but were just telling you that if you spent money on them you got ripped off and should steer clear of buying anything from that guy again since he obviously mislead you to think theyre amazing heads when theyre not.

 

They have hardened seats already installed so that's not an issue. 882 heads are supposed to be prone to cracking as well, but I know of a truck with .595 lift 383 in it. It's pushing at 600hp, never cracked when he was told they would, it's been raced 300 times. He just recently passed away, but he was a master mech.

Not trying to argue, just make a point about heads "prone to cracking".
I wasn't planning to keep these but use them for now bc they are the only heads I have that I know will support high lift. My stocker lo5 heads definately wouldn't. Thanks for the help guys!! I appreciate the info, I knew nothing about them in stocker form, now atleast I know something.

 

You came to the Internet, asked what you had, and we told you.

You don't like what you found out.

That doesn't keep it from being true.

How is anything any of us tell you here, going to change what those heads ARE?

How much polish does it take to make a turd shiny?

That's what you've got: a turd that's been polished to a high gloss. Did that change what it IS?

All of the

you can muster, won't change WHAT THEY ARE.

You've got heads with a poor bowl shape, bad chamber design, and now after porting, are probably SCARY thin in all sorts of places, as those early smogger heads tend to be.

Here's what happens to old crap heads when they get "ported" and people graunch larger valves into them.



THAT is basically what you've got. Doesn't matter how many races they have on them; it's not as though repeated usage adds metal. You have NO WAY of knowing howthin they are or how stressed the metal is or whether the stress of unbolting and rebolting them is all that it will take to finish them off. It's all a matter of risk and probability.

But, since you're determined to somehow be assured that you somehow made a wise decision by buying those before doing any research (a classic behavior pattern ... see http://en.wikipedia.org/wiki/Post-pu...ationalization and http://en.wikipedia.org/wiki/Cognitive_dissonance and http://en.wikipedia.org/wiki/Sunk_cost for an analysis of the feelings you are presently enjoying), right now you have 2 choices.

You can either put them on your motor, or not.

If you take the first choice, one of 2 things will happen.

Either it will run better, or it will run worse. Which by the way includes not only "how much power they make", but also, their effect on gas mileage, their longevity, and lots of other factors that go into the "quality" equation. You may well find they are "better" than L05 heads in some respects, once you spend enough MORE money to install them; who knows.

Your move.

 

Like I said before, I wasn't arguing, no need to be a douche about it. Just making a statement that I didn't understand. My heads look nothing like what you picture looks like. Were those 126 heads(3970126) bc there was another set of 126 heads that the first numbers are not the same, they are like 3900126 or something like that. Even if they are bad heads, the valves and springs and all could be used on another set, right? I wasn't arguing, heads and cams confuse me. Never understood how the numbers and all work in equation.

 

No your heads probably don't look like those in the pic, as yours are low-perf smoggers where the ones in the pic are one of the "better" old castings. I believe they're 186 but I could be wrong, as I just ganked the pic from somewhere a long time ago. Yours should be open on the spark plug side, sort of more "vertical" all the way out to the "squish" area just off the deck on these, such that the plug should look like it's coming through a little tower into the chamber. That's how the large-chamber low-compression low-output smogger head chambers are built.

Kind of more similar to this:



Except that these are 081 (87-up 305 non-swirlies) being set up with 1.94" intakes. But the chamber design is similar.

The point of the pic is, how thin the metal around the valves gets in these old factory castings, when the seats are cut. Some castings (041, 492 and 292 for example, as well as some of the earlier ones without bolt holes like 461 and 291) have enough meat there to withstand it, the low-perf ones however generally don't because there was no thought that such a thing could ever happen to them. But it's risky to some extent with any old stock heads because quality control was so poor back then. Casting core shift was MUCH worse with the old World War II technology in use at that time than it is now. Some amazingly crappy things were allowed to happen because they didn't think it was important, didn't have ways to check it, thought it would cost to much to prevent or scrap or whatever, and so on. Problem is, out here in meatspace, WE don't have any way to know either, until a failure occurs. Just like stock market hype; absence of failure in the past is no guarantee of success in the future.

Yes the valves and springs can probably be transplanted, if suitable recipient castings were obtained.

 

Well, it's starting to come together. This is my first build, I have always built cars to look amazing, never to run amazing. I got frustrated with having a beautiful car that is slow. I have 550$ into my build right now, that's motor(complete), 1.6rr, rpm intake, valves, springs, heads, open air filter, filter lid/bottom plate, and headers. Everything I have is brand new, just got lucky.... Except motor and heads. The heads were $75 ( came with brand new valves and springs valued at $160 together), so basically I bought the valves and springs for a steal and he threw in some crappy heads? At least I don't have to buy valves and heads, lol.... That's some possitive

 

Anyways, if I used these til I find a set worth it, what would it do to my compression, it's a 95 stock roller lo5. I think 9.3:1 factory, I think

 

the l05 should have 64cc heads on it now. with the 64cc heads the CR should be at 9.3:1, unless you got a lower output version. if you do, it would be at 8.75:1. either way. if you swap the 64cc heads for the larger 76cc heads, your CR is gonna plumit and youll wind up with LESS power. so if the l05 has heads on it. use them. pull the valves and springs out of the 76cc heads, and toss them for scrap.

 

I was contemplating that. I found someone with some 081 heads, I was going to see about.... The. Port polish and bigger valve them and see about that, was really wantin to find some better heads that aren't vortecs, don't wanna buy another intake. Was going to pull the valves and springs and sell them and then sell the heads for what I paid, to get rid of them. I was going to use the heads just to use them then I opened my eyes to the fact the high chambers would kill compression

 

chances are the only people that would buy those bare heads off you are people who dont know any better. toss them in the scrap pile and dont try to rip someone else off.

 

Yeah good point!! That would be cruel and unusual punishment

 

You never know someone may want em for a truck or something. I mean just because they're not high performance doesn't mean they won't get someone back on the road with an old 350. Something else I will point out is they "could" be a higher CR than 70-72cc. Just because they came outa the factory at 70-72 doesn't mean they weren't shaved. Who knows what was done to parts that old without seeing them especially in a hi-po environment.

Something else I will say is that for a first time build to get someone's feet wet they are probably fine for that. No they wouldn't make 600hp like a set of AFRs or Pro1s might but at the same time is it really going to kill his build overall? We're not talking him throwing 200 of juice on this thing just a street car that will likely see the high side of 5K on a rare occasion.