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How bad did I screw up my head choice?

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HotRod777

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I’m doing a big-block swap into my 1966 Coronet. I found a 1966 440 out of a Chrysler (pad stamped B440 12 29)
I’m doing this as a driver/ essentially stock pump gas car so it’s just going to get re-ringed/ bearing/ gaskets (it has no measurable ridge). The heads were off it to inspect the bores. They are flat-top pistons typical of what I always saw in early to mid 60’s 10:1 engines. The seller (who is a mopar parts vendor) gave me a choice of heads.
He had a set of 158’s that were off the motor or a set of 452’s. Doing I quick search I seen the 158’s were 1.60 exhaust (essentially a 516 head).
I chose the 452’s figuring I would get ‘about’ low 9’s on compression and have hardened seats. I plan to use .020 steel shim head gaskets.
My question is... am I estimating this right or am I way off and going to end up with 7.75:1 or something miserable???
 
To answer your question about if you're 'estimating right' we need more info...namely piston height at TDC. 452 volumes are iffy too, I have a set that cc' d at 89 but you don't know unless you check because milling, valve jobs etc all have an effect..it doesn't take much to change the static ratio so you really need to know whatcha got, a few cc's here or a couple of thousandths there can make all the difference..
 
Never heard of “158” heads...... those must be pretty early.

As stated, get the piston to deck clearance, then you can ballpark the CR.
 
The 158 head he said was 1966-67 Chrysler only. (Which this motor is) He said Dodge and Plymouth got the 915’s in 1967 that were closed chamber with 1.74. He said the 158’s were carryovers (basically re-numbered 516’s from the years prior, closed chamber, 1.60).
I’m not looking for exact numbers, let’s just say if a 516 (77ish cc) head yields 10:1... what does going to a 90cc head on the same engine do?

And, a quick ruler and feelers gauge looks like they are .100 in the hole.
 
Lots of assumptions. Assuming stock bore and stroke, flat tops with no valve reliefs .100 in the hole, 020 by 4.4 bore steel shim, and 90cc heads, Wallace calculator says 8.5/1.
Same assumptions, but with 75cc heads, 9.66/1.
To get an accurate number, all of those variables have to be actually measured.
Actual measured c/r was usually at least half to three quarter points less than mopar claimed, factory rating.
 
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.100 in the hole is deep.
You’ll be hard pressed to make 8:1 with a flat top piston
 
beanhead said:
To answer your question about if you're 'estimating right' we need more info...namely piston height at TDC. 452 volumes are iffy too, I have a set that cc' d at 89 but you don't know unless you check because milling, valve jobs etc all have an effect..it doesn't take much to change the static ratio so you really need to know whatcha got, a few cc's here or a couple of thousandths there can make all the difference..
Click to expand...

This. All this stuff is so old, you don't really know what's going on until you you measure. An original 67 piston will be about 0.085" in the hole. 66 might be the same, or deeper in the hole.

67 Chrysler's with 440s had 915 heads as well. The 350 HP version had the 1.60" exhaust valve.
 
So I guess I screwed up picking those heads.
Here is more detail of my plan, maybe everyone can help with picking the lesser of the evils.
This is going in a 1966 Coronet post, converting from a /6. I want to build it as a ‘homage’ to a plain-Jane stripped sedan with just a big wedge engine option. It’s going to have a stock iron intake, manifolds and 2.5 duals, stock air cleaner, etc. 27” tall 235 radial and I have a 2.94/grip right now but might be able to squeeze the budget for 3.55’s. The car will never see the track, and likely never over 70mph. I just need it to sound “lumpy” at idle and ignite the tires if you stab it at a stop sign. I’m putting this car together for my father and that’s what he wants.

So... stick with the 452 heads and 8.5-ish compression and put in a whiplash cam or similar...

Or... find 516’s or (maybe) 915’s and run a lesser cam, like a comp 270/470?
 
My .02......

Lumpy cam with exhaust manifolds = dud.

Forget what it sounds like and put a cam in it that allows the motor to be happy with the ex manifolds on.

I did some digging....... found this:
“2406158 – 1967, 440 B/RB-series big-block, 2.08/1.60 valves, 73.5cc”

Never heard of them before.
Looks like they should def help with the compression.
 
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Lumpy cams,low compression, and no gear, willnot be happy together. You must match the cam to compression and usage to be happy.
My advice is to get a cam two steps smaller than the one you think you want.
 
These guys are spot on. If I could add one thing, and I'm speaking from past screw-ups of my own, you have it apart now, take the little bit of extra effort to measure everything exactly and then you will always know what you have... Quick measurements and assumptions and you'll always be wondering. You can get a deck bridge and dial indicator from Amazon to measure the TDC piston depth and stroke for not much $$. You can have the heads cc'd at a shop, or you can make your own kit with a piece of plexiglass, a medical grade syringe and some green rubbing alcohol(check YouTube for some videos) The thing is, if those heads were 73.5cc from the factory and have ever been worked on the volume could be pretty low and you could end up with more compression than you want, which will cause all kinds of hell especially with iron heads. If you can get some good measurements now, you'll know exactly what size head gasket to put in there and what your final compression will be.
 
if the heads need rebuilding, consider aftermarket aluminum heads. My heads needed all valves, guides and seats, plus clean up decking, etc. Sidewinders from Marsh were the same price, give or take. Just a thought.
 
I'm useing 452's, TRW flat tops, .039 gasket, .050 in the hole. Calculates to around 9.3:1 I'm useing the Summit 6401 cam. Average compression 160-165. Seems to run quite well, good vacuum, average fuel mileage with 3.23s out back.

One thing eveyone says about the 452 head is they have hardened seats. Well they did from the factory but with any machine work, the hardness was taken off the surface of the seats. I use mostly E free gas. During the summer running around, I might throw some 10% 93 in the tank but I'll add the Stabil 360 to cushion the blow. Does good.
 
tmaleck said:
if the heads need rebuilding, consider aftermarket aluminum heads. My heads needed all valves, guides and seats, plus clean up decking, etc. Sidewinders from Marsh were the same price, give or take. Just a thought.
Click to expand...

This. And you'll make a bunch more power too.
Most people don't fully understand how important a good set of heads are. A good set of factory heads is two things; the right casting number plus $1200 of work and parts (no porting). If the heads are not both of those things, they're likely junk.
 
Std bore 440, pistons down the hole .100, steel shim gasket, heads milled to 82cc = 9.0cr.

That’ll work fine.
 
I would recheck your deck height. .100 seems an awful lot for a 66 440. Maybe .080. mill the heads .020 should put you around 9:1
 
Thanks for all the responses. However the plan has changed. See my newer post in this same section titled “383 cam and springs”.
The 440 and 452’s went away. Turns out the “ran when parked” 1966 440 ended up having 4 spun rod bearings that look like it was driven for 2500 miles that way. It literally offset ground the crank 1/4”.
The new plan is a 383 and 915’s. Detail are in my other thread.
 
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