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516 vs 915 heads

Posted By: Nick Mineau

516 vs 915 heads - 04/27/10 03:15 AM

can anyone tell me if one or the other flow better. bolth have 1.6 exaust valves. i want to install 1.74 valves in whichever ones i choose. the 516 are in much better shape and i already own them and run them on my mild 440. the 915's arent mine and i would have to spend 300 $ just to buy them plus the $ for the machine work. tight buget. looking for some more getty up than the 1.60 valves offer. i heard mixed things. some say the heads are the same others say the 915 will flow better. im not planning on any porting.
Posted By: RapidRobert

Re: 516 vs 915 heads - 04/27/10 03:25 AM

915's would flow better but without a doubt I'd read dulcich's iron head porting articles in mopar muscle and it'd break your budget now but I'd consider some alum ones w the kind of cash refurbishing the iron ones is going to cost to do em right
Posted By: KillerBee

Re: 516 vs 915 heads - 04/27/10 03:27 AM

If your on a tight budget I would stick with the 516's.
With bigger exhaust valves the 516's will flow very close to the 915's in stock form.
The experts claim if you max port them, the 915's flow a little better but spending big $$$ on stock steel heads for maximum performance is not money well spent with all the aluminum head choices out there.
I have a set of 516's with larger exhaust valves on my bone stock 1966 440. With a MP .509 cam and Holley 750 DP in a heavy street car it ran high 11's.

Attached picture 5949246-challistrip.jpg
Posted By: Nick Mineau

Re: 516 vs 915 heads - 04/27/10 03:50 AM

what size valves did you run. any porting. i would be very happy with those times
im running a 3300 lb duster
Posted By: KillerBee

Re: 516 vs 915 heads - 04/27/10 04:06 AM

Quote:

what size valves did you run. any porting. i would be very happy with those times
im running a 3300 lb duster



I went from the smaller 1.6 exhaust to the (newer stock) 1.74 size. Intake valves are stock size.
I did a little backyard smoothing of the ports, I didn't re-shape anything or remove any material, I might have made it slower.
Shortblock is a 40k original mile 1966 440, never touched, bone stock.
Heavy all steel street Challenger(less fiberglass T/A hood).
Hemi 4 speed with 4.10 rear gear.

I would think 11's would be real easy in a lighter A body as long as you get it tuned and dialed in right.
Posted By: Nick Mineau

Re: 516 vs 915 heads - 04/27/10 04:19 AM

thanks. ill have a machine shop install som 1.74
Posted By: JohnRR

Re: 516 vs 915 heads - 04/27/10 02:52 PM

Quote:

If your on a tight budget I would stick with the 516's.
With bigger exhaust valves the 516's will flow very close to the 915's in stock form.
The experts claim if you max port them, the 915's flow a little better but spending big $$$ on stock steel heads for maximum performance is not money well spent with all the aluminum head choices out there.
I have a set of 516's with larger exhaust valves on my bone stock 1966 440. With a MP .509 cam and Holley 750 DP in a heavy street car it ran high 11's.



I'd be interested in seeing the flow sheets on a set of stock 516 vs. the 915 on the intake side since 915's have better intake ports than a 516.
Posted By: KillerBee

Re: 516 vs 915 heads - 04/27/10 03:12 PM

Quote:

Quote:

If your on a tight budget I would stick with the 516's.
With bigger exhaust valves the 516's will flow very close to the 915's in stock form.
The experts claim if you max port them, the 915's flow a little better but spending big $$$ on stock steel heads for maximum performance is not money well spent with all the aluminum head choices out there.
I have a set of 516's with larger exhaust valves on my bone stock 1966 440. With a MP .509 cam and Holley 750 DP in a heavy street car it ran high 11's.



I'd be interested in seeing the flow sheets on a set of stock 516 vs. the 915 on the intake side since 915's have better intake ports than a 516.



John, many moons ago I believe Dwyane Porter flowed and then carved up a set of 516's and 915's.
IIRC the 516's with matching 1.74 exhaust valves installed flowed close to the 915's until he started really removing material. The 516 heads had a few humps and bends in the port passages that restricted flow and couldn't be removed without ruining the heads.
Obviously once the Edelbrocks heads came out spending big $$$ to go all out modifying factory steel heads was pointless.
Posted By: R/T1968R/T

Re: 516 vs 915 heads - 04/27/10 04:08 PM

This page has stock flow #s on these heads

http://users.erols.com/srweiss/tablehdc.htm
Posted By: forphorty

Re: 516 vs 915 heads - 04/28/10 03:37 AM

According to Dwayne Porters flow bench, the 906 intake port flows much better than the 516. And as Dwayne mentions, the 906 and 915 port are basicly the same. http://www.moparts.org/Tech/Archive/bb/62.html
Posted By: Mr.Yuck

Re: 516 vs 915 heads - 04/28/10 02:37 PM

9.15's have bigger exhaust valoves and are worth more. however if the 516's are in better shape it might be a wash. my 516's have 2.14/1.81 valves, port work and flow very well. before you spend a nickle on either check out parts here or on other sites. you may be able to pick up a done set for around 4-500.
Posted By: Pale_Roader

Re: 516 vs 915 heads - 04/29/10 01:15 PM


I'm chewing on this exact dilemma myself right now. I've got a nice, ready to go set ov 516's and a set ov 915 cores that need everything. I have a new set ov Manley 1.81 exhaust valves to use. I was just gonna have the machine shop cut the 516's for the big exhaust valves, clean up the ports, cut the guides a bit shorter for a bigger cam and call it a day.

But for an extra $300 i could have the same stuff done to the 915's (sell the 516's to make up some ov the $500 cost).

I'd feel better about porting the 915's as i have never done 516's, and i'm a little wary ov going too far. I've done 906 and 915 heads so far with good results.

So yeah, Hmmmm...
Posted By: RT540

Re: 516 vs 915 heads - 01/27/21 01:21 PM

Hi, old thread I found.

Have a good set from a -66 440 that I would like to have hardened seats pressed in for unleaded fuel. My machinist does not want to go up in valve diameter from 1,6" to 1.74". He thinks we will go in to water channels.

Anyone know which size valve seat he could use safely for these old 516 heads?
Posted By: Mr.Yuck

Re: 516 vs 915 heads - 01/27/21 03:41 PM

I had a set of 516's that had work, they flowed very well, They had 1.81, 1.74 valves...no issues. You might want to look online for a set of used iron heads that are done. You'd be surprised how cheap you can pick them up.
Posted By: an8sec70cuda

Re: 516 vs 915 heads - 01/27/21 04:17 PM

There was a set of 516s needing to be rebuilt on one of the Mopar Facebook pages for sale earlier this week I believe for $100.
Posted By: moparx

Re: 516 vs 915 heads - 01/27/21 06:22 PM

maybe by the time you machined the castings for a 1.74 hardened exhaust seat insert, it would hit water, whereas if just machining 516's for a 1.74 valve, water wouldn't be hit ? shruggy
just from my experience BEATING on all the early stuff since the beginning of unleaded gas, exhaust valve recession in the head hasn't been a problem.
as a disclaimer, however, this hasn't been done with 10:1 and up race engines. brand X and Y have had way more problems with valve recession in my experience.
possibly the "heads were made of better material" statement is somewhat true ?
what is the cost of rebuilding iron heads these days ?
just a factory style rebuild with guide liners after the castings were crack checked of course.
or would that not be considered without adding hardened seats ?
beer
Posted By: RT540

Re: 516 vs 915 heads - 01/27/21 07:14 PM

Bought a complete 66 440 and will buy Edelbrock street for the short block. Cylinders look good. Will keep the original pistons. The 516 heads would go on a 383 in my D200-70 with 906 heads. To add som CR. Would have the heads cut to have a CR close to 9:5. We have 95octan here in Sweden as regular and 98 as premium fuel.

Maybe possible to run these without new seats? Total miles for a summer are limited to shorter trips, mostly moving stuff with the 8 foot bed.
Posted By: DrCharles

Re: 516 vs 915 heads - 01/27/21 08:10 PM

I have a pair of 516's that I had hardened seats and 1.74 exhaust valves installed. Bowl blend too. They don't leak. shruggy
Posted By: fouronthefloor77

Re: 516 vs 915 heads - 01/28/21 01:47 AM

I had some 906 heads rebuilt with hardened exhaust seats, With new valve seals and OEM valvesprings the tab was $674
Posted By: Cab_Burge

Re: 516 vs 915 heads - 01/28/21 02:14 AM

Originally Posted by fouronthefloor77
I had some 906 heads rebuilt with hardened exhaust seats, With new valve seals and OEM valvesprings the tab was $674

he is in Sweden, probably harder to get them fix over their.
It might be cheaper, easier and better to buy a new set of aluminum heads like 440 source, Speedmasters or Pro Comps scope twocents
Posted By: calrobb2000

Re: 516 vs 915 heads - 01/28/21 02:39 AM


hi

i have done several sets with hard seats installed for 1.74 valves for 383 s . use bronze guide liners also !

light port and blend and no problems . work good .045 milled off for compression .

intake side milled also .

Posted By: AndyF

Re: 516 vs 915 heads - 01/28/21 04:04 AM

Originally Posted by an8sec70cuda
There was a set of 516s needing to be rebuilt on one of the Mopar Facebook pages for sale earlier this week I believe for $100.


Sounds like $100 too much. I throw 516 heads away when they come in my shop.
Posted By: RT540

Re: 516 vs 915 heads - 01/28/21 10:22 AM

Originally Posted by Cab_Burge
Originally Posted by fouronthefloor77
I had some 906 heads rebuilt with hardened exhaust seats, With new valve seals and OEM valvesprings the tab was $674

he is in Sweden, probably harder to get them fix over their.
It might be cheaper, easier and better to buy a new set of aluminum heads like 440 source, Speedmasters or Pro Comps scope twocents


I would rather buy Edelbrock street heads, than the above china brands. I will get Eddys for the 440 build for a Satellite 68 I bought in december.

The 516 would be a budget build with homeporting the bowls. But I guess there is limit on how much to spend before new alum heads would be a much better choise.
Posted By: RT540

Re: 516 vs 915 heads - 01/28/21 10:24 AM

Originally Posted by calrobb2000

hi

i have done several sets with hard seats installed for 1.74 valves for 383 s . use bronze guide liners also !

light port and blend and no problems . work good .045 milled off for compression .

intake side milled also .



Thanks for the info, any size or even better part nr for the hard seats? My machinist is a metric for mm instead of inches.
Milling the intake side is a good move.
Posted By: calrobb2000

Re: 516 vs 915 heads - 01/29/21 12:39 AM


S B I

is the brand he uses but i dont konw the part no .
Posted By: RT540

Re: 516 vs 915 heads - 01/29/21 11:58 AM

Sent an e-mail to tech at S.B. international asking for the smallest outside diameter hard seat for a 1,74 valve.

Will have my machinist give me a total cost for both seat work and bronze guides, then will se if these heads will either end up in the attic, or on the 383-70 D200 truck of mine.
Posted By: RT540

Re: 516 vs 915 heads - 01/29/21 08:31 PM

Originally Posted by calrobb2000

S B I is the brand he uses but i dont konw the part no .


Here is the answer from SBI : I would recommend the SB1812-12 for the 1.74” valve.

Depth 7/32
Exact O.D. 1.8175
I.D. 1-5/8
Posted By: an8sec70cuda

Re: 516 vs 915 heads - 02/01/21 07:58 PM

Originally Posted by AndyF
Originally Posted by an8sec70cuda
There was a set of 516s needing to be rebuilt on one of the Mopar Facebook pages for sale earlier this week I believe for $100.


Sounds like $100 too much. I throw 516 heads away when they come in my shop.

That's all well and good if your customer has enough of a budget to spend $1200+ on new cylinder heads. Many do not.
Before you say you'll spend that much on rebuilding stock heads...that all depends on where you're located and who's doing the work. I've had stock cast iron heads rebuilt and spent way less than I see a lot on here quoting.
All depends on the end goal, but a pair of 516 heads can be made into very capable high performance heads that make good power.
Posted By: Sniper

Re: 516 vs 915 heads - 02/01/21 11:21 PM

Originally Posted by an8sec70cuda


All depends on the end goal, but a pair of 516 heads can be made into very capable high performance heads that make good power.


Not without added costs over buying a core and just rebuilding them. Then you are stuck with iron heads that cost about as much as the Aluminum heads and don't make more HP, not to mention the AL heads still have room to improve if you want to go that route.

Stock rebuilt they are fine. You start porting and such then you have to think hard about how to spend your money.
Posted By: Gtxxjon

Re: 516 vs 915 heads - 12/16/21 12:08 PM

If you have to spend more than $600 on a refresh, then you must go Aluminium.

But I would never spend time and effort on a 516 anyways!

I have wrecked several pairs trying to get the exhaust ports 'into shape'. sawzall ozbbq

Some are cast with the very bad roof port bulge that cannot be enlarged.

But I recently came across some 516 castings 1964 and 1965 that have the later style '915' 'LARGE' exhaust port, go figure? realcrazy

All the 1966 heads that I have ported and subsequently ruined have the collapsed roof...

So I cut my old 1966-516 race heads up to see why?

I'm guessing its a 'foundry flaw' with damaged casting-moulds from 'over use'...

Pictures to follow for anyone who 'maybe' interested lol... fan
Posted By: RT540

Re: 516 vs 915 heads - 12/16/21 01:08 PM

Here´s my 516 from -66 that now have 2,14 and 1,74 Milodon valves.
New valve guides and hardened exhaust seats plus valves cost me as much as Edelbrock street heads.
Live and learn!

Attached picture IMG_4681.jpeg
Posted By: ek3

Re: 516 vs 915 heads - 12/17/21 01:12 AM

one thing i learned long ago, brand new heads can be junk out of the box. one of the most important parts on your engine! how well i know the sound of a great valve job when it first fires it off... you should spend whatever it takes to get them right no matter what head you use. if it cost to much , then you should save some more money! up
Posted By: Gtxxjon

Re: 516 vs 915 heads - 12/17/21 10:35 AM

Stuff is expensive to get done in Euroland these days!

I worked at a place called ''Rovercraft'' a specialist V8 workshop.
We very rarely did iron head work since the Millennium...

Seat work was always Aluminium heads and guides were 'knock out and re-fit new ones.
The last set of iron heads I had done was approx £250 to fit seats and 3-angle cut, per head!

Guides are always worn and some heads are on their second or third set of guides...



But now I see a different issue with heads!

Worn out 'stainless steel' exhaust-valve 'stems and seats', at an alarming rate...

The stainless is much softer than the older steel/alloy exhaust valves?

Now there is 'head warpage' too!

I took a set of Mopar performance '452 aluminuim' heads off a low mileage 440ci engine and one head was badly BENT/BOWED etc!

It was in fact 1/2mm which is 0.020 thousanths... fan

Once it had been machined flat the outer combustion chambers were way out of cc spec.
So you have to reseat the valves to match the centre cylinders and re-shape the chamber to get the volume right again.
Then you have to re-machine the rocker pedestal channels as they are 0.020 bowed as well...

All in all it was much work I would have called it scrap myself... spank spank drumhit

You fix one problem and get another... drinking
Posted By: Gtxxjon

Re: 516 vs 915 heads - 12/17/21 10:51 AM

If you own a pre 1966 car/truck and you are only grocery getting, then 516 heads are FINE!

My grocery getting days in a Mopar are well and truly over for me...

I love Mopar iron heads and am always happy to spend an hour or twenty on them.

My own bug-bear' with 516 heads is, they ''break through' real easy on the exhausts, even with mild port work... panic violin fan

They have a bad exhaust port and that's how it is... ozbbq



The 'Stan Weiss' Flowchart is mind-blowing and takes some reading!

516 Intakes around 220 cfm which is poor.

No 915 'raised port' flow numbers, but they are basically 'closed chamber 906's.

A very trick 906 intake will get you somewhere near too 300 cfm's...COOLIO...

So if you can get 300cfm with any head you need approx, 75% for the exhaust too...(225 cfm).

There is one set of stock '2.08-1.74' 906 heads with 250cfm flow.
If you can start with those numbers you are onto a winner lol... drive
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