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Another street/strip 440 rebuild
#1638700
06/26/14 04:50 PM
06/26/14 04:50 PM
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Joined: Jun 2014
Posts: 41
MA
mopar67440
OP
member
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OP
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Joined: Jun 2014
Posts: 41
MA
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This is my first time posting here...been mostly a reader and have learned a lot, thanks all.
Well, I'm finally at a point in my life where I can finish my life long project.... 1967 Coronet 500. This will be the 6th, 1967 car I've owned since 1985.
Would love some input on the following engine combo that I had built over 20 years ago in my last project. I thought it ran really strong on the track and was very streetable once tuned. Loved it so much, I've decided to pretty much keep everything the same with the exception of new pistons and rods.
1969 block 0.030 over
KB236 piston
Eagle rods
6 qrt pan/pickup/windage tray & HV pump
906 heads
single layer 0.020" head gasket
509/292 108 cam
stock 6 pack rockers & push rods
Torqer single plane intake w/ 1" spacer & no exhaust xover
700CFM DP Holley (50cc pumps, 37 nozzle, 72 prim, 82 sec jets)
Mallory Hyfire ignition sys. w/ 12 initial, 36 total advance (may need to revisit this with change in gas formula)
1 7/8" headers
2.5" dual exhaust w/ xover
3200 stall
3:91 gears
modified B727
26" BF Goodrich
super stock leaf springs
My only concern would be with the new KB pistons and compression using the 509 cam. According to the KB website, a KB236 piston with unmodified open chamber heads (approx. 88-90CC) and 0.020" head gasket, compression will be approx. 10-10.5.
Thoughts...
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Re: Another street/strip 440 rebuild
[Re: mopar67440]
#1638701
06/26/14 05:19 PM
06/26/14 05:19 PM
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Joined: Jun 2006
Posts: 5,159
CT
GTX MATT
master
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master
Joined: Jun 2006
Posts: 5,159
CT
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Would be a good runnner. Nowadays lots of guys are running 440Source aluminum heads or Eddy RPMs instead of 906s. If you're starting from scratch they cost about the same, and make more power than stock 906s. 10:1 or 10.5:1 compression would be fine with aluminum heads and good quench (not sure if you're familiar with that). It will probably be trouble with 906s. You're actual compression with those pistons would likely be closer to 9.5:1 though. Lots of guys will tell you to run a different cam (newer design), but theres nothing wrong with the 509s. Modern cams have more aggressive ramps which require more spring pressure and will wipe a lobe faster. The 509s are also fine with stock rockers. If you run the Stealths or Eddy RPMs the supplied valve springs should be adequate also. Comp also sells a version of the 509 that works well. Lots of guys run 3 inch exhaust now since it is more readily available. Id run a 750 or 800, but a 700 isn't terrible. Overall, that combo still pulls hard. I've had 4 '67 B bodies since 2007 myself 
Last edited by GTX MATT; 06/26/14 05:20 PM.
Now I need to pin those needles, got to feel that heat
Hear my motor screamin while I'm tearin up the street
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Re: Another street/strip 440 rebuild
[Re: mopar67440]
#1638702
06/26/14 05:32 PM
06/26/14 05:32 PM
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Joined: Jan 2003
Posts: 74,948
U.S.S.A.
JohnRR
I Win
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I Win
Joined: Jan 2003
Posts: 74,948
U.S.S.A.
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Quote:
My only concern would be with the new KB pistons and compression using the 509 cam. According to the KB website, a KB236 piston with unmodified open chamber heads (approx. 88-90CC) and 0.020" head gasket, compression will be approx. 10-10.5.
Thoughts...
That's going to be a problem unless you don't have a problem running race gas .
Hopefully you haven't wasted money on those pistons yet .
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Re: Another street/strip 440 rebuild
[Re: JohnRR]
#1638706
06/26/14 05:44 PM
06/26/14 05:44 PM
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Joined: Jan 2003
Posts: 21,064
Niles , Ohio
therocks
oh wait.but hey.lets see.oh yeah.
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oh wait.but hey.lets see.oh yeah.
Joined: Jan 2003
Posts: 21,064
Niles , Ohio
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I run 12.5 Ross domes in my street 440.It did have 516 reworked heads.Now it has Stealths with .039 gaskets.It will run all day long on pump gas.Only time I get clatter is if I really lay into it in like 1st.It has a Comp .588 cam with IIRC around 325 duration.Now when I really want to have fun I add 112 race gas.Same thing at the track.Rocky
Chrysler Firepower
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Re: Another street/strip 440 rebuild
[Re: mopar67440]
#1638707
06/26/14 06:40 PM
06/26/14 06:40 PM
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Joined: Jun 2006
Posts: 5,159
CT
GTX MATT
master
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master
Joined: Jun 2006
Posts: 5,159
CT
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Quote:
I already have the 906's w/ heavy springs/dampers. The aluminum heads are just a little rich for my blood at the moment.
Also, the engine ran strong with the 700cfm right up to 6500. At the suggestion of a friend, I tried both a 750 & 850, and after tuning them both, I found the larger carbs were not as responsive, and there was really no diff in the et's, so I went back to the 700.
Stick with it then.
I thought the 236s were the flat tops and 237s the quench domes, which is why I said you'd probably be lower compression above. As far as the compression goes, you have all the parts. Why don't you measure and figure out what it actually is? Did the shop take your heads and actually set the quench distance? If you have the quench set up right you might get away with 10:1 with the 509 cam.
Now I need to pin those needles, got to feel that heat
Hear my motor screamin while I'm tearin up the street
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Re: Another street/strip 440 rebuild
[Re: GTX MATT]
#1638708
06/26/14 09:35 PM
06/26/14 09:35 PM
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Joined: Mar 2005
Posts: 3,138
Central NC
gch
master
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master
Joined: Mar 2005
Posts: 3,138
Central NC
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The lazy response on the larger carbs may have been due to the Torker intake.Maybe not  509 cams like compression and it should run well you will just have to be careful not to get into detonation in the upper rpms once you build some cylinder pressure.I bet it would like more initial advance. I would thin an RPM intake or street dominator intake would be a better choice and would run at least a 750cfm carb if it were mine. If you could sell your heads and get the 440 source heads you would be great on compression and likely run faster. 
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Re: Another street/strip 440 rebuild
[Re: gch]
#1638709
06/27/14 12:45 AM
06/27/14 12:45 AM
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Joined: Aug 2006
Posts: 2,141
junction city oregon
viperblue72
top fuel
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top fuel
Joined: Aug 2006
Posts: 2,141
junction city oregon
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I agree that it's a good combination. Pushing it for pump fuel though. Just throw in a gallon of 110 with every tank if it pings a little. May as well run a thicker head gasket as well. Either that or run aluminum edelbrock rpm heads. Run a 1.6 rocker. I would install a proform hp main body on that carburetor also. I would bump the stall up another 500. 
Last edited by viperblue72; 06/27/14 12:48 AM.
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Re: Another street/strip 440 rebuild
[Re: JohnRR]
#1638710
06/27/14 12:49 AM
06/27/14 12:49 AM
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Joined: Aug 2006
Posts: 2,141
junction city oregon
viperblue72
top fuel
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top fuel
Joined: Aug 2006
Posts: 2,141
junction city oregon
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Quote:
Quote:
Yup...the lower end is a done deal at this point...balanced and assembled. No cam yet though and I can always change the head gaskets if need be.
the KB is a step head piston , what is the distance between the step head and the open part of the chamber ? That piston was designed to mimic a closed chamber head when setup properly , you chose the worst people KB made for that application , but probably because it was the only one they had.
I had my hands in a build with 452's and step head pistons , Diamond made me these to get 9.5 with 89cc head.
A flat top 0 decked will get you 9.5
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Re: Another street/strip 440 rebuild
[Re: Mr.Yuck]
#1638712
06/27/14 12:24 PM
06/27/14 12:24 PM
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Joined: Jun 2014
Posts: 41
MA
mopar67440
OP
member
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OP
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Joined: Jun 2014
Posts: 41
MA
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I was considering a thicker composite head gasket as suggested(0.020 to 0.040) to reduce compression, but this will certainly reduce quench, and I fear it may result in either no change, or even increase the likelihood of detonation at heavy loads.
As suggested, I will up the initial 12 degrees, and note any detonation at 36 and drop total back a bit if need be to keep it in check. But I'm also thinking if I can get away with the 160 therm verses 180 now that I have a 3 core high efficiency rad/shroud combo, plus dialing in the right octane, I may be able to keep it at 36 degrees total.
As for the carb tuning, I was very meticulous when dialing in all 3 carbs (700, 750 and 850), and definitely proved the smaller carb gave me better throttle response, quicker 0-60, slightly better 1/4 mile et's, and the same upper rpm limit of 6k.
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Re: Another street/strip 440 rebuild
[Re: mopar67440]
#1638714
06/27/14 01:14 PM
06/27/14 01:14 PM
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Joined: Jan 2003
Posts: 74,948
U.S.S.A.
JohnRR
I Win
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I Win
Joined: Jan 2003
Posts: 74,948
U.S.S.A.
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Quote:
I was considering a thicker composite head gasket as suggested(0.020 to 0.040) to reduce compression, but this will certainly reduce quench, and I fear it may result in either no change, or even increase the likelihood of detonation at heavy loads.
You said the heads were stock , 88-90 cc , how far above the deck is the step above the deck and did you have the chamber depths equalized ?
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Re: Another street/strip 440 rebuild
[Re: GTX MATT]
#1638718
06/27/14 03:12 PM
06/27/14 03:12 PM
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Joined: Jan 2003
Posts: 16,376
dogdays
I Live Here
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I Live Here
Joined: Jan 2003
Posts: 16,376
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According to the KB catalog, the piston has comp height of 2.057, the step head is 0.075". The total of the dome and the valve reliefs ADDS 4.8cc to the head volume. This is a common mistake, KB is the only company that talks about reducing chamber volume with a dome as NEGATIVE ccs. So adding to the volume above the piston comes in at POSITIVE ccs.
According to the KB website, their stated compression ratios are for zero deck, 0.040" head gasket, 0.030 overbore.
For the KB236 and 88cc heads the stated compression ratio of 9.9:1.
If you do a Web search for the KB236 you will most likely go to the Summit catalog page and they have their own compression ratio computer, which uses the positive ccs for the piston dome and dish as subtracting from the combustion chamber volume. If you use the KB numbers in the Summit calculator you are guaranteed to get wrong answers. Guaranteed.
Using a deck height of 10.725 and stock piston and rod lengths puts the piston 0.025" down in the hole, which with your 0.020" gasket puts your setup the same as the KB standard, give or take a few cc. But if your heads have not been milled, they are 88 to as much as 93cc, meaning your actual compression ratio should come out between 9.75:1 and 9.9:1.
It might run on pump premium, or need a little water injection. IMHO it's on the upper limit.
One other thing, the thinner head gasket and the 0.075" step are helping fight detonation, I wouldn't change that.
Other things that will help are keeping the engine and intake manifold cool, and keeping the mixture on the rich side.
R.
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