452 or 516 heads??

[73-Charger-Canada]

Hi Guys, would love to hear your opinions on this. I have two sets of 440 heads, both good and clean. Older mid 60s 516 head (closed chamber, and without cc'ing them I've read they are anywhere between 78.5 - 84 cc) and 452 heads. The 516 CC look WAY smaller as a combustion chamber than the 452 heads I have (88cc) do. Here's the rest of the build.

440-6 block, forged crank, 6-pak forged rods, and Sealed Power L2266f pistons (adv. 8.66:1 compression with stock 88 cc head).

originally the pistons sat about 0.100 below deck surface, and I had the deck evened out, so now they sit about 0.080 below deck. The block was in such good shape so I did not need an overbore. So, I used this calculator http://www.csgnetwork.com/compcalc.html and found these results:

516 head (at 78.5cc) = 9.77:1
425 head (at 88cc) = 9.03:1

The heads have similar flow numbers compared with one another according to hot rod mag test a while back. http://www.hotrod.com/how-to/engine/5115-cylinder-heads/
Here's the trick, the 516 castings are going to cost me $300 extra. Is 0.74 increased CR worth an extra 300 bones to anyone here? Would I feel that on the street? or is it worth it to just rebuild my own 452 heads, and call it a day? As always, opinions appreciated!

[Sublime/Sixpack]

If your calculations are correct, personally I'd go with the 452 heads @ 9to1 comp. 

[73-Charger-Canada]

I really appreciate the input! Can I ask why you wouldn't go for the higher compression? I'm just trying to see all the sides of the argument

[A383Wing]

the 516 heads have the small exhaust valve....won't flow very well

[73-Charger-Canada]

Yes, if I went with the 516, I would get it re-ground for the 1.74 exhaust valve instead of the 1.60. Good point though. So that's two in the 452 column, keep em coming guys

[heyoldguy]

Please note that the flows in the charts are for the 915 head and not the 516. The flows for the 516 are considerably less than the 915. You can put a 1.74 exhaust in the 516 and they will still suck. Stock for stock, the increased airflow from the 452 will be of greater benefit than the compression increase from the 516.

[Sublime/Sixpack]

I really appreciate the input! Can I ask why you wouldn't go for the higher compression? I'm just trying to see all the sides of the argument

You didn't state what cam you plan to install, what fuel you plan to use, or what exactly you're expecting from this engine, but based on your original post I got the impression that your 440 build would be relatively mild. Considering that, and that your heads are cast iron, and if you plan to use pump gas I personally would rather go a little lower on the compression ratio than go too high and have an engine that pings.

As mentioned the 516 heads have the smaller exhaust valves so you'd want to open them up then do some port work to get to where the 452 heads are stock. Plus the 452 heads have induction hardened exhaust seats (not usually a big deal but a plus just the same).
Hope this helps.

[firefighter3931]

The only advantage with the 516's would be a slight increase in static compression. As mentioned the decrease in flow will negate any increases in static compression. I'll take the flow over the static increase every day of the week ! 

The only time I would ever use that head casting would be a smogger 400 with the pistons .180 in the hole that has 7:1 static. At that point the 516's would be worth it. 


Ron

[73-Charger-Canada]

This is immensely helpful, thank you all for taking the time. this is a mild street 440, and I'm using the Summit 6400 cam http://www.summitracing.com/int/parts/sum-k6400/overview/.  I have decided that I will use my 452 heads, for all of the reasons you have suggested and the money saving benefits. By the time I bought the 516s and had the work done to them, I would have been $600 into them anyway! That's almost enough to start looking at aftermarket aluminum heads. So, 452 it is, and thank you all very much for your help. Now do I go Chrysler Blue, or Chrysler Turqouise.... 

[73-Charger-Canada]

ALSO forgot to ask. When I took apart my 452 heads, my intake springs and my exhaust springs were different. The exhaust springs all had the internal damper in them, where the intake did not. Also, the exhaust had a roller retainer, and the intake had a flat retainer. Is that par for the course with 452 heads, or was that swapped in by the previous owner?

[heyoldguy]

I've heard of the exhaust rotators coming on truck/motorhome engines before but have never personally seen them on the 452 heads.

This may throw a small wrench into the 452/516 debate, but in your circumstance I still wouldn't run the 516 heads. And, let me make it perfectly clear, the only reason I ran the 509 camshaft was it was laying on the shelf and I wasn't going to use it for anything. I paid $50 for a set of hydraulic lifters that I wanted and the 509 came with them. The 509 wasn't a good selection for this type of build, it just happened to be basically free.

Here is a 440 dyno test starting with the K6400 camshaft and stock 906 heads. Then progressing to the 509 cam and slightly ported 516 heads.      http://www.forabodiesonly.com/mopar/showthread.php?t=249866&highlight=1972+440

[73-Charger-Canada]

thanks for that read about the low comp 440 build!! that's a huge encouragement for me, since it's basically the engine i'm building exactly. I can still make good power on the 452 heads, and if I want to upgrade to a higher compression head and different cam down the line, then I know what type of power I might expect.

I've looked into the roller retainer a little bit, I'm going to replace them with a flat retainer. I don't want my valves rotating. Now for picking springs. Can anyone suggest a set of springs that are economical and match the k6400 camshaft?

[firefighter3931]

Can anyone suggest a set of springs that are economical and match the k6400 camshaft?

Comp Cams #911 will work fine with that cam and in the future should you upgrade. This is a single spring with dampner, fits the stock retainer(s) and clears the factory umbrella valve seal.

http://www.summitracing.com/parts/cca-911-16



Ron

[Sublime/Sixpack]

 Now do I go Chrysler Blue, or Chrysler Turqouise.... 
[/quote]

Hemi orange.   

[Stegs]

I've heard of the exhaust rotators coming on truck/motorhome engines before but have never personally seen them on the 452 heads.

This may throw a small wrench into the 452/516 debate, but in your circumstance I still wouldn't run the 516 heads. And, let me make it perfectly clear, the only reason I ran the 509 camshaft was it was laying on the shelf and I wasn't going to use it for anything. I paid $50 for a set of hydraulic lifters that I wanted and the 509 came with them. The 509 wasn't a good selection for this type of build, it just happened to be basically free.

Here is a 440 dyno test starting with the K6400 camshaft and stock 906 heads. Then progressing to the 509 cam and slightly ported 516 heads.      http://www.forabodiesonly.com/mopar/showthread.php?t=249866&highlight=1972+440

thanks for posting that link. I have a 8.5:1 compression 440. basically stock rebuilt with low comp pistons (unknown to me) This makes me have hope that i can get some decent power out of my lower compression 440.....

may not win any dyno pulls, but give my car enough boost to keep the smile on my face!

I think headers are something i should look.....maybe 516 heads....

[ragin sonny]

even if you put bigger exhaust valves in the 516's, I think the port is different / more restrictive than other castings

[73-Charger-Canada]

So update... two of the valve seats in the 452 heads are cracked (dammit) so I'm going with the 516 heads. I bought comp springs and retainers to go with it. So, at least there's one step forward according to that link to low comp 440 power building! From reading up on the 516 heads, and anything else without a hardened seat, the chance of the valves screwing themselves is pretty low (especially if I run a lead additive and zinc-y oil). I'm still way ahead budget wise than I would be buying aftermarket aluminum heads. I'll let you guys know how it goes in!

[flyinlow]

I had a set of '66 440 heads  years ago (not sure of the number)  and put the 1.74 exhaust valves in them . It did not work that well. Seat problems after a few thousand miles.   

I like to buy horsepower at $10-15 each.  Edelbrock or other heads add about 60 HP and reduce weight. About $30 a HP , but they are brand new . I think you can get down to about 75CC with heart shaped combustion cambers.

[aerolith]

Hi Canada Charger,

I have a Canadian built 71 GTX with 3462346 heads, (first gen 'flat-port' smogs) pretty much the same all the way to 1978!

How did it go with the 516 heads?

I have just ported a couple of pairs of 516 for my Moparmates 1965-383ci engine.
Both sets have bad seat recession even in the intakes doh!

I have had one set 'treated' to hardened seats and the other set left normal and both have now got 1.74 exhausts.
The set with the hard seats needed extra large intakes too 'at 2.14' which go in easily.

But the seat-inserts had to be cut very shallow due to water just under exhaust seat and very easy to cut into!
How do I know this, well I've done a few sets over the last 40 years and scrapped a few too...
This is their biggest drawback, which is, a poor exhaust port shape in the joining web area...

But the 452 is probably the best head ever made, except they seem to have cracking issues?
Is this something to do with the 'flame hardening' process in later smog heads...

Koffel says ''the flatter 452 port is easier ''to port'' and flows the most cfm ''under the curve'' for a race engine...