906vs516 heads

[furyus 67]

Got a question for the gurus. A buddy of mine has offered me a set of 516 close chambered heads for free. Are these better than the 906 heads that I have? Would they be worth some head work on them or should I hold out for some 915 or better?

 

[bulldogchesty]

I'm not sure, but I think the 516's have the smaller valves.

 

[68plymouth383]

Whaaaaattttttt.... The 516 are small valve closed chamber heads. The 915 are large valve closed chamber heads. Both are well suited for mild to high compression engines. You need to pick the best head for your engine components.

 

[bulldogchesty]

Posted at the same time.

 

[68plymouth383]

Right. But the what reference was at Damon. The title is 906vs516. But in the body of the post it's 915vs516....

Posted at the same time.

 

[twostick]

That's a good price!

Better is relative. They are better because they have smaller closed chambers which will increase CR and if you build for zero deck, gives you good quench. Good quench helps prevent detonation which open chamber 906's are more noted for.

They are less better because they have smaller exhaust valves and the ports don't flow quite as well as the 906.

Sooo... If you are building a C-body friendly torque monster, the 516 can fill the bill for you IF they are fresh and have had the exhaust valves upgraded to 1.81's with hardened seats.

If they are virgin 100,000 mile castings, the cost of properly rebuilding them could put you close to, perhaps even more than a set of 440Source Stealths.

Kevin

 

[stubs300]

The 516's that I have been running were stock for a while. I did a mild port job, gasket match, added the 1.74 exhaust valves in them and the difference is like night & day. Good Luck

 

[furyus 67]

Thanks guys. The 906vs 516 was in reference to the 906's I've got now. My build is mild, 284/484 Mopar perf cam, comp valve springs,stock valves, weiand intake , 650 edlbrock carb, stock crank,pistons,rods. Wondered if the 516's were any better than the 906's. Or if I would be better off building the 516's over the 915's.

 

[furyus 67]

I edited the original post. I WANT the 915's and have the 906's.

 

[furyus 67]

Whaaaaattttttt.... The 516 are small valve closed chamber heads. The 915 are large valve closed chamber heads. Both are well suited for mild to high compression engines. You need to pick the best head for your engine components.

That's what I'm trying to figure out. Sorry for the miss type.

 

[68plymouth383]

No problem. I prefer the 906 heads. I'am running them on my 440.

That's what I'm trying to figure out. Sorry for the miss type.

 

[Landyacht]

I believe the 516 castings were only used in the 383 motors and had smaller exhaust valves and ports, somewhat restrictive the 915 s hade a little better flow and still retained the closed chamber design. the 906 castings came along a little bit later and had an open chamber design but had larger intake runners and the best flow characteristics out of all the big block wedge heads except for maybe the max wedge heads. I am not quite sure. my memory isn't quite perfect Get yourself a copy of" How to Build Big Block Mopars" by HP books. They have a whole section about cylinder heads. This book is a must have if you plan on rebuilding big block mopars.

 

[70bigblockdodge]

The 915 and 906 are the same head except for the chamber shape, and not all 915 castings are 1.74 exhaust valves. The 516 have a little different port shapes jut at less than .500 lift they all work about the same. Anything bigger than 1.74 exhaust valves will be shrouded or very close to the cylinder wall on a small bore 361/413.

 

[furyus 67]

I'll pick that book up landyacht. Thanks for all the input guys.

 

[detmatt]

I believe the 516 castings were only used in the 383 motors and had smaller exhaust valves and ports, somewhat restrictive the 915 s hade a little better flow and still retained the closed chamber design. the 906 castings came along a little bit later and had an open chamber design but had larger intake runners and the best flow characteristics out of all the big block wedge heads except for maybe the max wedge heads. I am not quite sure. my memory isn't quite perfect Get yourself a copy of" How to Build Big Block Mopars" by HP books. They have a whole section about cylinder heads. This book is a must have if you plan on rebuilding big block mopars.

The 440 in my Imperial had 516s on it originally. I replaced them with 915 non HPs that I had bigger exhaust valves swapped in. The non HP 915s had the same size valves as the 516s.

 

[1978 NYB]

Don't forget to have hardened seats installed on the exhaust side when rebuilding those heads....

 

[twostick]

Don't forget to have hardened seats installed on the exhaust side when rebuilding those heads....

And that is the problem with any iron head. By the time you have hardened seats installed, new guides, (not liners) new valves and springs and machine work, you have just spent the price of new aluminum heads.

On the OP's engine, depending on what year it is, the pistons could be over .100" in the hole so the quench advantage of the 516 could go away leaving the bump in compression the only advantage but an advantage that .484 cam will like.

Like I said before, if the heads are fresh with at least hardened seats for an upgrade, I would use them. If it's a choice of which head I rebuild, I would use neither because the 906 will need all the same things addressed at the machine shop that the 516's do which equals $$$ spent that can buy new heads that will outperform all but a max effort $$$ iron head.

Obviously if you have a new set or Manley valves and hardware sitting on the shelf and a buddy with a machine shop, most of the above is moot, but for most of us the best bang for the cylinder head buck is aluminum.

Kevin

 

[detmatt]

I had to put less than $1000 into my 915s including parts and I'd do it again. How much for a decent set of aluminum including getting them checked before installing?

 

[70bigblockdodge]

Uh-oh here we go again with the alum vs iron, another unending argument.

 

[1978 NYB]

If I did any head upgrade.....aluminum would be the direction I would go.