yup....thats right......we're talkin' 16+ second combos!!

you guys have all seen them at the track.
its often a fairly nice looking resto-type muscle car with maybe a different carb and a mild cam.
a full bodied car, that looks basically stock, with an unhappy first-time-ive-ever-been-to-the-track-with-my-car owner, who was sure it should be running a couple of seconds quicker than it is.
that perplexed look on the owners face as he stares at the 16.XX or even 17.XX on his time slip tells the whole story.

so, the question is......how do you take a car that would have run at least mid-15's with a fairly used up 100% sock 440, with the 12" converter and 3.23 gears.....then rebuild the motor, upgrade the cam and a few other trinkets....and slow it down one second plus???

well my friends......i have a set of 906's in my shop now that go a looooong way to answering that question.

a customer of mine has a 1969 440 car thats getting restored.
the car was purchased as a project, and came with a freshly machined 440 that was supposedly ready for assembly.
well, when the parts get back to the shop and inspected, its discovered the engine parts had been sitting around in a damp environment for a while, and will need some clean-up before being put into service.
the heads got sent to me for a once over.

now, keep in mind had these parts not gotten rusty from sitting around....there is every chance they would have been put into service as-is.

this set of heads had hardened exhaust seats installed, all new guides, all new valves, valve job, flat milled, and new MP 933 springs.
seems harmless enough, right? i mean....how bad could they be?

well....after i got them apart and gave them a look over i knew they werent going to be the hot ticket for making power.
not necessarily a big problem, since this is basically just a stock type rebuild for a restoration.
as long as they arent too much worse that an OE head, they'd be fine.

some things were done that just didnt even make sense.
like....all the seats had two thick coats of red Dykem(lay-out dye) on them......but no seat touch up done after the application of dye.....so why was it even there???(Dykem as a seat protectant??)
the new valves also had a nice coat of Dykem all over them, but they had been refaced afterward.

the seats had been cut with a cutting system(as opposed to stones), and several of the exhaust seats had some severe chatter.
when the grooved iron guides were installed(probably my least favorite replacement guide), they spot facted the entire original guide boss on top of the head off, and just left the 1/2" replacement guide hanging out in the breeze.
not really a "problem" per se, but i found the seal arrangement amusing. the OE positive style intake seals now had nothing to grab on, so they were now umbrella seals.
the new guides were also left at the OE height, so trimming would have been necessary with many cam choices.

after disassembly, i brushed the assembly lube(paste type moly cam lube) from the guides to check the fit, which felt okay.
when you do this stuff day in and day out, you get where you can tell if there is an obvious seat alignment issue without even breaking out any tools.
these exibited those trends, so i stuck a pilot in the guide and kissed a few seats with a stone to see how the contact pattern looked.
the exhaust barely even touched on one side, and the intake hit maybe 1/3 of the way around.

okay, so the seat runout is not good.....and the intake seats have been sunk into the chambers about .030 or more, without a relief cut made into the chamber, so the valve is essentially sitting in a little pocket with a sharp vertical edge all around it.
thats not gonna be good for flow.

originally i wasnt even going to flow them....but these seemed extraordinarly bad......so on the bench it went.
the exhaust seats were the std size listed in the catalog for these heads, which leaves a noticable step under the insert.
while this looks like its going to kill the flow......it surprisingly doesnt really seem to have much effect, and in fact, this exhaust port was actually better at high lifts than an untouched low milage 906 head i have at the shop.

so, how bad was the flow as they came to me?

lift----I/E
.100--42.4/45.3(not a typo....int was less than ex @.100 )
.200--96.8/86.4
.300-153.8/125.0
.400-199.7/146.6
.450-211.2/152.9
.500-217.0/158.8
.550-222.7/162.6
.600-228.5/164.3
.650-232.3/165.1

after i took it off the bench and reviewed the numbers i called the customer to tell him these heads had lowered the bar for 906 head flow.
the flow from .450 or so and down was horrible.
once the valve was well clear of the seat, you can see the port itself wasnt that bad for a stock head, breaking 230cfm.
but with a cam that would likely be under .500 lift for this application......the area under the curve was quite a bit worse than an untouched OE head.

you'd like to think that when you got your stuff back from the machine shop that it wasnt worse than it was when you brought it there.

since its rarely the case when its just operator error when things look this bad(its usually a combination of operator error and worn out equipment), i didnt trust the new valves that had been refaced to have no(or very little) runout.....and when i chucked a few up in the valve grinder, my suspicions were confirmed.
bring the valve up to the wheel.....and you get that hit and miss sound of a few thou of runout.....but salvageable at least.

i took some pics of these jewels.....dont know how they came out, and the camera is at the shop, but i'll try and post a few pics tomorrow.

so.....imagine the entire build done with the same machining practices, the same attention to detail as these heads....and the picture gets clearer on how you make a 14-15 second factory muscle car into a 16-17 second weakling, fearing every Neon or Civic with a fart can in their neighborhood.

It's just sad that there are shop's out there that do that kind of work, I guess the guy's at that shop figured that there is no way that a stock engine could run any worse than it did before it came to their shop.

thanks for clearing that up, its somthing ive always wondered about,its somwhat embarassing when your at the track surounded by all your chevy buddies and a cherry looking roadrunner pulls up and runs a 16, OH and by the way ,i havnt been able to get to the tack in quite awhile but last time out at 1/8 mile track the car ran a 6.008 with a miss,theres a 5 in it for sure, you got the combo right on the spot.

happens all the time

VERY interesting read Dwayne! Can't wait to see the pictures! RandyB

its often more puzzling when you talk with the owners of the cars and listen to the list of stuff thats been done to the motor.
"its got 6-pac pistons, balanced, heads are blueprinted with a 3 angle valve job, balanced, rods resized with ARP bolts, (cam brand of your choice) with 22X @ .50....." etc, etc.

you hear the list of parts, and it seems like a straight forward enough build, and you wonder why its such a slug.
no one ever really thinks to themselves....."maybe the machine work is just crap".

for comparison, here are some numbers from a very clean OE 906 head.
this head is in excellent condition for a 100% stock head, and could actually be put back into service with just a light touch of the valve seats. doesnt need any guides or anything. this is as good of an example of an unmolested 906 as ive seen, although its not the best flowing stock 906 ive tested.

stock 906, OE valve job, OE valves, no back cut
lift----I/E
.100--59.6/48.4
.200-121.8/95.1
.300-182.5/125.7
.400-213.9/145.3
.450-219.6/149.1
.500-223.5/151.6
.550-228.5/152.9
.600-231.2/156.2

thats 30cfm better than the "16 second" head at .200 & .300, which is a big part of the flow area with a .450-.500 lift short duration cam.

i'm not saying its always the case when you see a particularly poor running OE type car that its the fault of the machine shop......but i have to believe that its at least a contributing factor in many cases.

A head shaker.Only thing worse is the stroker aluminum cyl hd ,all the best stuff 12 or 13 sec car.Some of the supposed shootouts in the mags have been brutal.Quality machine work matters.

okay, so the heads are here....and need to be fixed.

whats the course of action?

if it was going to be more of a hot street build, or restification with headers and perhaps an aftermarket intake manifold i would have opted for oversized valves to restore some of the valve height in the chamber.
but its really just more of a restoration deal, with manifolds and OE induction, and i didnt feel there would be enough benefit in performance(or any benefit) to justify the expense of new valves.

the seat runout was poor enough, and the placement of where the seat interfaces with the valve was pretty "high" on the valve face that it would end up requiring sinking the valves roughly another .015" before everything cleaned up.

i followed that with a plunge cut into the chamber to unshroud the valve, and a 75deg bowl cut, leaving the bottom angle about .100" wide.

then i blended the bowls, bullit nosed the guide bosses, and knocked the intake short turns back.
with a back cut added to the valves, i ended up with this:

lift----I/E
.100--71.2/55.3
.200-150.5/102.5
.300-210.5/138.9
.400-247.7/168.9
.450-251.5/180.3
.500-256.1/185.1
.550-248.4/189.2
.600-246.5/191.8
.650-245.8/194.3

this is the same two ports, and the same valves, after "fixing" them.

gains:

lift----I/E
.100--28.8/10.0
.200--53.7/16.1
.300--56.7/13.9
.400--48.0/22.3
.450--40.3/27.4
.500--39.1/26.6
.550--25.7/26.6
.600--18.0/27.5
.650--13.5/29.2

thats some serious gain in flow from .500 and down.....which has got to make a noticable improvment in power.....since it came with a very minimal increase in runner volume.

hopefully the rest of the motor will get looked over, and any problems addressed.....which should keep this car out of the dreaded "16 second zone".

just a couple other tidbits.....

i see this more often than not with rebuilt OE Mopar heads....the rocker shaft bolt holes are still full of crud.
these were particularly bad. one oil feed hole on each head was also full of gritty sludge.

the valves are sunk far enough that with aftermarket retainers the installed height was tall enough to need more shim than could be "located" by the register on the head, so i machined the heads for spring cups.
i also replaced the grooved iron guides with bronze pieces, and shortened them so they could be used with a .550-.600 lift cam, should that situation ever arise in the future.

measuring the head bolt boss thickness showed the heads had only been skim cut previously.
a spot check of one chamber on each head showed them at 90 and 92 cc's.
i cut them down to 89cc's, which will put the motor at about 9.5:1cr with a Fel-Pro 8519 gasket, zero deck, and TRW L2355 pistons.

It's amazing what people can screw up if they really put their minds to it.

The main inspiration fro writing my manual some 15+ years ago now was the same type of 15-16 second slugs Dwayne's talking about....cars that sounded like legitimate 11-12 second runners when I was at the 1990 mopar nats and wouldn't fall out of a tree going down the track.

Wow...
Amazing how a shop can screw up a set of heads, and claim they are done. Although you posted a table of gains, I had to put all the numbers in Excel and make this table to save, it was so amazing without a lot of trick porting. And you make a good point about low lift flow.

Also a good point about head cc's and compression ratio. The 90 cc Mopar BB heads are common, and some guys that think they have 10 CR, are way less than that, especially if their block is on the tall side, putting the pistons deep down in the hole.

anyone care to share their 15/16/17 second 440 stories??

there must be a few on here......

this is a close as i can come...

a friends 69 GTX, around 70,000 miles
stock heads, fresh VJ, Crane 272H cam(216/228 @ .050, 112lsa), 933 springs, untouched bottom end except for new timing set.
stock intake, exhaust, "remanufactured" Carter AVS with correct part number on it. stock jetting.
stock single point distributor, recurved.
Turbo style mufflers.
11" Trans King converter
3.91 gears, sure grip
L60-15 M/T "sticky" rear tires

14.40's, dont recall the speed......probably like 95-97mph.
this was around 1986. it was at Quaker City in Ohio for one of Car Review Magazine's street car shoot-outs.
this was the second year thay had this event, and my buddies car was like #45 out of over 200 entries.
Bob K. was running high 12's at that show.

after my buddy got a feel for what was and wasn't considered "legal" for this type of event, i made a few changes to the combo for the next season......but he never did go again.
BTW.....he drove the car from Vermont to Ohio to participate in that event.
i ended up re-ringing the bottom end, doing a mild pocket port to the heads, and installing the bigger Summit cam(224/234 @ .050, 114lsa).
with 4.10 gears and G70-14 Coker red stripe repo tires it went 13.70's at over 100mph at the local track.


heres another one:
another friends car, a 68 Charger with a late 70's low CR 440, high miles and all original with a spread bore Holley 650DP on it and a cheap set of 1 3/4" headers and 2 1/4" exhaust.
4 speed, cheapo G60-15 non-sticky street tires, crappy stock type clutch that slipped on the gear changes, 3.23's or 3.55's(cant remember for sure), sure grip.

as i recall i got it to go like 15.40-ish....and i seem to remember it was over 1/2 second slower with the owner driving it......so that would put it almost into the 16 second zone.

that was also around 1986 or 87, and by this time my heap was already well into the 11's

So...inquiring minds want to know - when given a pile of garbage that some other shop is responsible for, do you, the machinist ever pick up the phone and call that other shop and tell them what you found?

Dwayne...It's good to see you posting tech info like this again.

I've missed your posts.....

thanks for the chart Jim

the changes can be seen more easily in that format.

i can tell you one thing.......if i would have had the time, and a stock-ish 440 core lying around.....i would have loved to do a back to back dyno test with these heads.

you dont often get a chance to test something that bad, in so many ways.
poor seat and valve work, along with dismal flow.....its a recipe for disappointment.

heres another way to get ultra-low performance from your BB Mopar.
several of the OE replacement piston suppliers have pistons that yield very low compression ratios.
a friend of mine is getting ready to put together a mild street 440 for his 66 Coronet, and someone gave him a set of cast replacement pistons for a stock type rebuild.
the C/H is like 1.940.
so, if you used an uncut block, these pistons, and combined them with a set of heads like what i have here....you'd get the double whammy in low performance.
at a nominal 91cc's, and those pistons being .137" down the hole.....you'd have a motor with 7.74:1cr......no flow from the heads.....and combustion pressure leaking by all the valves.
how promising does that sound for your restoration type vintage muscle car?

its not at all uncommon for a non-performance oriented machine shop to use pistons like this for a rebuild, because they often just dont check to see how a particular combination of parts will work together, and how much they differ from the OE parts they are replacing.
its listed in the catalog for the application.....so they just use it.

with even the most mundane of rebuilds....a little research and thought can go a long way in avoiding the "16 second blues"

oh, and i told my friend he wont be using those pistons....even if they are free.

How about screwed up combos?

528 with stock 906's, 0.525" crane hyd cam, manifolds, 4.10s and 3500 stall.

My worn out 413, 484 cam with template ported 452's, 1.75" headers, 2500 stall and 3.55's.

In a lil street race who'd ya think would be out front and pulling away?

Imagine if it was clean and assembled. How many cam and convertor changes would have been given to get the car out of that 16 second time slip...........

Goes to show how much attention to detail matters