516 heads >>>>> do i really quench ?

[rog_allen]

Do we really need the quench ? 71 RRP b-body, 73 440 , 4 speed , 373 rears , building for street muscle
1973 440 cast crank , bored 30 over , forged flat tops , malry rings , balanced rotating assembly ,
edie dual plane semi highrise alum intake, 750 double pumper, hot MSD dist with coil and box , 1 7/8 hooker full length headers with 3 inch pipes out the back, magnaflow muflers , true duels , high volume eddie mech. fuel pump
haven't chose cam yet but thinking a comp with around a .525 lift

my heads are almost done ,
516 close chamber heads , fully ported with 208/188 oversize stainless valves ,stainless seats, all new guides, milled .040 and intake milled .040, and port matched

now ...... my pistons are below the block -.100 with the gasket ,
I know now all about the quench and what it does and should be .035 to .055 and .040 is best ,
has anyone here let it go ?
we are hoping to dyno soon and hoping to get 500 pluss hp out of her ,
whats your ideas on this ?
is there a cheep fix ?
what will I notice if its let go like this in performance ?
thanks

 

[69Bee]

1) Unless you get Keith Black pop-up pistons to get the quench, it won't happen easily. You could use steel shim head gaskets, and deck the block. Assuming you are using stock 0.038" gaskets, your deck height is approximately 0.062". Using these head gaskets (MOP-P5155237) at 0.025", or (MRE86754) at 0.020", then square and deck the block to achieve a deck height of approximately 0.015" (cut 0.047"), and this will achieve a quench of 0.040". If you could use different pistons, you could minimize the amount cut off of the block.

2) If you haven't put the valves in yet, I would use 2.14" Intakes, and 1.81" exhausts. The 1.88" exhaust valves will hurt flow with your intended use.

 

[rog_allen]

great advice matches up with all the searching ive done ,talked to my great friend that is working on this for me ,looking like we are going to mill the block and get hold of machine shop and go with 2.14.s , he never replyed to me on the 1.81 exhausts you suggested

thank you very much !!!

 

[rog_allen]

Well they never started on the machining on the 516's heads yet (well they cleaned and magnafluxed them ) dont really want to deck the block .so we put a hault on them, going to bring my 452 heads in for porting and go with higher compression pistons ,
1) whats your thoughts ?
2) full port job ?
3) bigger valves ?
4) should we shave heads to compensate my pistons being down In hole ?
5) what pistons would you suggest ?
any and all thoughts will be very helpful on this ,
thank you

 

[Cranky]

Instead of spending all that money on factory castings, why not go for some Eddy RPM heads? Closed chamber and better combustion chambers plus by the time you make a set of factory heads flow as good as the Eddys, you'll have enough money in them that you could have paid for a head that not only will flow as good (if not better) but will perform better. As for quench, I get my engines as tight as I can short of the pistons hitting the heads for my intended use. However, I generally shoot for .030 with .040 being on the loose side and .025 being on the tight side with an eye being on how long the rods are and what they are made of. Can an engine perform well without having a tight quench? Sure but it will always be better with it. Lazy quench/combustion chambers means the probability for ping is higher....

 

[69Bee]

What he said... Today, you can get a set of aluminum heads rather inexpensively. The money you will invest to make you cast iron work as well, the aluminum will do the job better, and you can increase the CR 1 point for the better thermal quality of aluminum. You really should "Square" the block, in which case, you might remove about 0.010" to 0.015" to even out the decks. The last two I did, one Chevy was at an approximate 0.015" differential, and the Ford today was a 0.012" differential. There shouldn't be that much difference between deck heights.

 

[rog_allen]

quench ? what set of Eddys do u suggest ? and pistons if I need to get up higher in the hole ? I am on a tight budget but don't want to cut corners either ,
then to find proper cam ,

any and all advise im very thankful for
thanks :icon_pray:

 

[rog_allen]

Well we are up in the air on which way we are going on this build , Eddie's have angled plugs that wont go with my new hooker headers , yes I heard they make a set with strait plugs that cost more , indies wont work with my intake and I don't want to cut my hood for a scoop for the indy intakes rise higher ,

Anyone hear heard of these ?>>>>.....my buddy messaged me and said he knows of a set of iron heads. Chatfields record holder full port and polished++ ????? thanks

 

[wyrmrider]

Chill for a minuite
516s or 915s work fine with a "0" deck or close to it but will give you a greater than 6 Pack compression level
The 6 pack used the larger non wedge type head
so
what gas?
with my 440 and 915s we took the TRW 2.061 compression height pistons and cut a D shaped cup to lower compression to a real 9:1
Quench is about .030 ( yes the pistons are +.010 as the block took .030 to clean and square up)
You need quench unless race only with race gas- even then quench is better
Edelbrocks are fine but the require blueprinting out of the box as QC is non existent
516 and 915 and most open chamber heads require exhaust seats- I recommend Durabond
X2 on the valve recommendation unless truck or Motorhome- then run the Motorhome Valves
Cam
With comp, lunati etc all the catalogue grinds are inferior chevy grinds
Dig through their literature to find the real .904 lifter grinds or call Engle
on my combination I use a Jones [email protected] 204 @.050 and .303 lobe lift (around 450 with 1.5 rockers)
let me know if you find anything with that short durations and that much lift without being a HR
so what to do
the KB idea works and can be made to work with any head- but open chamber heads take more $$ and time
Nothing works with the piston down the hole except lots of heat
and the further down the hole the more throttle it takes to go the same speed and the more heat
do pocket port the closed chamber heads

 

[cryplydog]

rog, backup and get the correct piston comp. height, 2.061 . just my thought.

 

[wyrmrider]

rog, backup and get the correct piston comp. height, 2.061 . just my thought.

Correct
the 2.061 is the correct compression height (2 1/16)
flat tops with that compression height 915 or closed chamber heads and .035 quench will give you near 12:1 (with about a .040 gasket)
any less CH and it's hard to get the quench under .040
if you want less compression get the proper D Dished or reverse deflector KB or their Forged piston
once you get the compression in the ballpark for the gas you intend to run we'll talk cam

 

[rog_allen]

THANK YOU FOR ALL YOUR ADVICE ....... We canceled the 516 iron head work with our machinist just in time ..
We are going with Mopar 452 Aluminum heads P5153524 >>same as eddy's but strait plugs.... getting blueprinted and pocket ported ,new double springs for our cam, new arp keepers and retainers .... •84cc combustion chamber CLOSE CHAMBER
using srp pistons and zero decking block
thanks again

 

[wyrmrider]

THANK YOU FOR ALL YOUR ADVICE ....... We canceled the 516 iron head work with our machinist just in time ..
We are going with Mopar 452 Aluminum heads P5153524 >>same as eddy's but strait plugs.... getting blueprinted and pocket ported ,new double springs for our cam, new arp keepers and retainers .... •84cc combustion chamber CLOSE CHAMBER
using srp pistons and zero decking block
thanks again

good choice
have not worked with that head in years but anything edelbrock needs to be double checked
concentricity etc
If you have the equipt I od hone the valve stems and knurl, ream and hone the guides (more for oiling but it does find tight/ loose guides
dbl check the cc's- 84 is different than what the blueprint is for 915's and may affect your CR
for a cam I'd go to the jonesracingcams website and fill out the recommendation form
if you are going to run a FT soild or hyd post back
as you might have surmised I put detonation control ahead of port flow
you can have both!!

 

[rog_allen]

thank you for more great advice ... I am forwarding your advice to my friend who is doing my build with me so he can also let the machine shop know ... we already bought the cam 'comp xe275hi' hyd flat tappet 1.6 iskie adj rockers....... but will still look into ' jonesracingcams website ' hoping to order new heads this week . he is looking to get them whole sale threw a couple conections ..
will give updates and share the flow charts ... anything else you think of please share ...... thanks and good day to you