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Flat tops, 509, and EStreet heads? Am I OK?

BRYCE NORVELL

BRYCE NORVELL

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So I have my 440 out of my 67 coronet to do a repaint and put new headers in. Well of course it's gotten deeper lol
Here is a breakdown
72 block
Forged crank pro balanced
6 pack rods
Factory flat top no valve relief pistons
I have 906 heads with the bigger valves, double springs, 10deg locks, all installed.
509 cam.
I'm looking at the Eddy E-Street 74cc heads. But not sure if I'm good to go without reliefs in the pistons.

Screenshot_20210802-074429_Facebook.jpg Screenshot_20210801-211137_Facebook.jpg
 
Depends on what the compression height of the pistons are. Are they original 67 flat tops or.....??
 
Cranky said:
Depends on what the compression height of the pistons are. Are they original 67 flat tops or.....??
Click to expand...
They are 72 flat tops. I wanna say if memory serves they are close to 100 below deck ill check in a bit.
 
Measure the valve drop on both heads...... that will give you the answer as to whether you need to check the clearance or not.

Edit- if the pistons are down .100, you “should be” fine.
 
PRHeads said:
Measure the valve drop on both heads...... that will give you the answer as to whether you need to check the clearance or not.

Edit- if the pistons are down .100, you “should be” fine.
Click to expand...
Unfortunately I don't have the EStreet heads.
 
72 pistons should be .145 down the deck. 67s are about .080 down...either way...Plenty of piston clearance for that cam.
 
Camshaft will fit fine by your specs.
No need to even check piston to valve with 1.5 rockers
I have run that in my 440 with flat tops
and 0 Deck and well over .100 clearance
About 9 to 1 compression depending on gasket.
Recommend a thin Comp. gasket and not shim
with these heads
 
GTX JOHN said:
Camshaft will fit fine by your specs.
No need to even check piston to valve with 1.5 rockers
I have run that in my 440 with flat tops
and 0 Deck and well over .100 clearance
About 9 to 1 compression depending on gasket.
Recommend a thin Comp. gasket and not shim
with these heads
Click to expand...
I have factory rockers
 
BRYCE NORVELL said:
They are .095 in the hole.
Click to expand...
.080-.095 is pretty much what you will see for a 67-70 era piston. Most of the 68-69 pistons are taller but I have ran across several 68 350hp pistons that have same piston as what you have. In 71 350hp is a similiar piston with a dish. 72 is suppose to have the 8.2:1 low compression piston? But yours does not?
...I guess you really never know what mopar did, they were hard to out guess. You can replace a 72 and later piston w the 67 piston. The rings are the same height from the pin....maybe they have been swapped???
We have a 284xe in a 440 with the same pistons you have but with 2.08 valves. 2.14 you will lose some, but .090 down gives some valve clearance.
 
Last edited:
Curiousyellow71 said:
.080-.095 is pretty much what you will see for a 67-70 era piston. Most of the 68-69 pistons are taller but I have ran across several 68 350hp pistons that have same piston as what you have. In 71 350hp is a similiar piston with a dish. 72 is suppose to have the 8.2:1 low compression piston? But yours does not?
...I guess you really never know what mopar did, they were hard to out guess. You can replace a 72 and later piston w the 67 piston. The rings are the same height from the pin....maybe they have been swapped???
We have a 284xe in a 440 with the same pistons you have but with 2.08 valves. 2.14 you will lose some, but .090 down gives some valve clearance.
Click to expand...

The engine has been played with before. The crank was pro balanced at bay city Machine. All ARP hardware. This was back in 97. I bought it a year ago. It seems to have good parts.

I'll be posting a thread of what all I'm doing to it pos tonight.
 
My gut instinct is to clay the pistons and run a thicker head gasket if I had to
 
I think you will be fine with them that far down in the hole. I ran some wild *** guess numbers, and I get the compression ratio going from 8.32 to 9.40 with the 74 cc e-streets.
 
BRYCE NORVELL said:
Unfortunately I don't have the new heads. I have not ordered them because I'm not sure if I can use them
Click to expand...
I've run the 509 cam with 906 heads on stock '71 pistons with STOCK valves and it cleared just fine. The old Direct Connection book say that cam is right on the edge for piston-to-valve clearance with stock shim gaskets. I guess my point is, is that Cometic (I think) has a BUNCH of different, extra thick head gaskets available. As long as there isn't some issue with the larger valves that I'm not aware of, I think you could buy the heads, check them on the motor with clay and IF and I mean IF you have a clearance issue, it won't be by much....and you just use a slightly thicker head gasket. just my 2-cents
 
With the pistons that far down in the hole, you won't have significant "quench" anyway, even with the closed chamber Eddie's. I would say 95% you will be fine with the e streets, but IF it is too tight, thicker gaskets can solve the problem, and you will still have more compression and MUCH better head flow, even with the thicker gaskets. The only problem is the cometics need a certain deck finish (THEY say!) and they aren't cheap, compared to felpro.
 
I'm with everyone else.
Will work. No notches. Going to the e Brock head doesn't change the situation.
 
Only reason I suggest Cometics is that several times I have had
corrosion issues with Aluminum Heads and Iron Block with composition
gaskets (1008/1009)
 
Pistons down in the hole .145 with a 509 cam would be a dog! You will have no bottom end unless maybe a very high stall convertor. Either up the compression or change the cam.
 
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