cr 400 aussie head
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Laughing Gas
Joined: Jan 2006
Posts: 883
Likes: 7
From: New-brunswick,Canada
cr 400 aussie head
i would like to know my cr on a 78 400 with silvolite cast piston 0.030 over with australian 302-2v 57.8 cc's.i try cr formula but i'm missing some number.
bore 4.030
stroke 4.0
cc 57.8
piston dish volume ?
head gasket bore size,inches?
piston deck height?
can i used aussie head with these piston?
it will be very appreciate if someone can help me .
by the way i put this 400 in a 81 mustang,i 've made the motor support my self
and i used a c-4 trans,9 inch rear end.tight fit but works,never start the engine yet bec my block was not good.i got the piston .030 over,FC-268H-10 cam ,edelbroock performer 400,600cfm edl manual choke,oil pump, timing chain,aussie head ...etc.
bore 4.030
stroke 4.0
cc 57.8
piston dish volume ?
head gasket bore size,inches?
piston deck height?
can i used aussie head with these piston?
it will be very appreciate if someone can help me .
by the way i put this 400 in a 81 mustang,i 've made the motor support my self
and i used a c-4 trans,9 inch rear end.tight fit but works,never start the engine yet bec my block was not good.i got the piston .030 over,FC-268H-10 cam ,edelbroock performer 400,600cfm edl manual choke,oil pump, timing chain,aussie head ...etc.
Posting Legend
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Posting Guru
Joined: Dec 2002
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From: chicago burbs
i'll take a SWAG at it...
TMI "zero deck" 400 pistons are 1.722" CH, silvolite 1160 pistons are listed at 1.63" CH making 7.9:1. i'm going to say your slugs are in the hole about .092".
using this calculator,
http://raceabilene.com/kelly/hotrod/compression.html
i reconstructed a silvolite/stock 400 using 4.030" bore, 4" stroke, 78cc chambers, .041" thick gasket, 4.1" gasket bore, .092" deck clearance and 15cc dish to make 7.9:1 compression.
swapping the 78cc chambers to 57.8cc's made 9.29:1 compression.
now the question is, how much octane will it need?
TMI "zero deck" 400 pistons are 1.722" CH, silvolite 1160 pistons are listed at 1.63" CH making 7.9:1. i'm going to say your slugs are in the hole about .092".
using this calculator,
http://raceabilene.com/kelly/hotrod/compression.html
i reconstructed a silvolite/stock 400 using 4.030" bore, 4" stroke, 78cc chambers, .041" thick gasket, 4.1" gasket bore, .092" deck clearance and 15cc dish to make 7.9:1 compression.
swapping the 78cc chambers to 57.8cc's made 9.29:1 compression.
now the question is, how much octane will it need?
Thread Starter
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Laughing Gas
Joined: Jan 2006
Posts: 883
Likes: 7
From: New-brunswick,Canada
Ch
I look in my descripstion part for the silvolite piston and i found the comp.ht. is 1.630,but this number don't tell me anything.is it the distance from the center of the pin to the top of the piston? how you found piston to deck clearance?thanks for everyting guy
Posting Guru
Joined: Dec 2002
Posts: 2,003
Likes: 2
From: chicago burbs
correct, the Compression Height, or CH is the distance from the center of the piston pin to the top of the piston.
from this page, www.tmeyerinc.com/400Fordpistons.htm
i took Tim's figure of 1.722" from one of his "zero deck" pistons(second photo) and subtracted the Silvolite 1.63" from that. ~Voila~ .092"
then using the calculator in the other post, i "reverse engineered" an engine using the known inputs to find that a 15cc dish gives the 7.9:1 compression ratio that Silvolite specifies.
the .092" in the hole is the reason why TMI Tim went so far as to engineer and produce a piston that comes all the way to the top, or "zero deck". the quench factor is all but lost if the piston doesn't come close enough to the head. anyway, that's how i came up with the figures, like a said though, it's just a Scientific Wild *** Guess(SWAG) but it's gotta be pretty close?
from this page, www.tmeyerinc.com/400Fordpistons.htm
i took Tim's figure of 1.722" from one of his "zero deck" pistons(second photo) and subtracted the Silvolite 1.63" from that. ~Voila~ .092"
then using the calculator in the other post, i "reverse engineered" an engine using the known inputs to find that a 15cc dish gives the 7.9:1 compression ratio that Silvolite specifies.
the .092" in the hole is the reason why TMI Tim went so far as to engineer and produce a piston that comes all the way to the top, or "zero deck". the quench factor is all but lost if the piston doesn't come close enough to the head. anyway, that's how i came up with the figures, like a said though, it's just a Scientific Wild *** Guess(SWAG) but it's gotta be pretty close?
Tuned
Joined: Jul 2003
Posts: 455
Likes: 3
From: Berkeley
if you still need to replace your block, i would seriously consider using TMI's pistons with those aussie heads. the zero-deck pistons with a big dish (30cc) give you about 9.5:1 compression and good quench to control detonation, so you might be able to run 87 octane with the right cam. wish they had been available when i did my rebuild. instead, i used badger flat-tops and left the aussie heads on the shelf...
Postmaster
Joined: Aug 2001
Posts: 4,270
Likes: 5
From: Delaware
How were you able to use a C4 tranny?
Give me the advertised Intake Valve Closing angle for the FC-268H-10 cam, and I will calculate the Dynamic Compression Ratio. I think that 9.29:1 static CR is not too bad with that cam, but it all depends on the IVC.
Give me the advertised Intake Valve Closing angle for the FC-268H-10 cam, and I will calculate the Dynamic Compression Ratio. I think that 9.29:1 static CR is not too bad with that cam, but it all depends on the IVC.
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Laughing Gas
Joined: Jan 2006
Posts: 883
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From: New-brunswick,Canada
it's true,but how much money we be involve for those pistons? i'm trying to make a 400 with the best i can do. i'm on a budget to but i'm not to hurry and i read a lots of ford ''stuff'' and i know i would not stop before i can feel my two front wheels out of the ground.with some good slick.
81 mustang on two weels,i'm crazy for that! thanks for helping me.
81 mustang on two weels,i'm crazy for that! thanks for helping me.
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Laughing Gas
Joined: Jan 2006
Posts: 883
Likes: 7
From: New-brunswick,Canada
cam spec fc 268h-10(grind number)
intake lobe 268 degrees/
218 degrees at 0.050 inch
exhaust lobe 268 degrees/
224 degrees/ at 0.050 inch
valve lift
(1.73:1 rocker) 0.494-inch intake/
0.494-inch exhaust
lobe seperation 110 degrees
the probleme was not the c-4 it was the 400.I had to lift my motors mounts from the frame about 3 inch(3x3 square tubing) to clear my oil pan from the big bar in the front.I have to options.the first was to cut the bar and modified it to pass the oil pan(now i can close my hood) or to modified my oil pan to go around that bar.but i found 1 year ago a oil pan to fit in fox body,but it's for the 351w blocks.Now i have a big hole in my hood and one of my buddy gone make a one of a kind scoop for it,no big deal he said.a lot of sheet work .For the tranny i just bolt it on the crossmember of the transmission.luckely i found a yoke to fit on my driving shaft and in my c4but my driving shaft is to short by 3.5 inch,detail after the motor's gone be in.
218 degrees at 0.050 inch
exhaust lobe 268 degrees/
224 degrees/ at 0.050 inch
valve lift
(1.73:1 rocker) 0.494-inch intake/
0.494-inch exhaust
lobe seperation 110 degrees
the probleme was not the c-4 it was the 400.I had to lift my motors mounts from the frame about 3 inch(3x3 square tubing) to clear my oil pan from the big bar in the front.I have to options.the first was to cut the bar and modified it to pass the oil pan(now i can close my hood) or to modified my oil pan to go around that bar.but i found 1 year ago a oil pan to fit in fox body,but it's for the 351w blocks.Now i have a big hole in my hood and one of my buddy gone make a one of a kind scoop for it,no big deal he said.a lot of sheet work .For the tranny i just bolt it on the crossmember of the transmission.luckely i found a yoke to fit on my driving shaft and in my c4but my driving shaft is to short by 3.5 inch,detail after the motor's gone be in.
Elder User
Joined: Sep 2000
Posts: 936
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From: Bay area
I beleive Dan's question is more so the C4 was a small block tranny only, you have a big block trans bolt pattern.
Sure it was not a C6? Although you could have one of the stupidly rare block with both big and small bell patterns on it.
Sure it was not a C6? Although you could have one of the stupidly rare block with both big and small bell patterns on it.
Thread Starter
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Laughing Gas
Joined: Jan 2006
Posts: 883
Likes: 7
From: New-brunswick,Canada
c4
my bellhousing is bolt to my 400 and bolt to my c4 also.it's in 2 pieces.4 bolts hold my bell on my c4.i had a c6 before but i trade it for a 351M because i have a hard time to install in the fox body,the transmission pan was to wide and the transmision i've got is more smaller(pan).
Senior User
Joined: Feb 2004
Posts: 295
Likes: 0
From: conway arkansas
yea they can, not sure on the bolt count, however, they are somewhat like a c-4 in that, the bellhousing is interchangeable between motors, it is unique to an fmx but you can find em to fit pretty much any motor ford made in good years, you can also tell if its a c-4 or fmx by the case, a c-4 will have an all aluminum case including the bell housing and tail housing, as where an fmx has an aluminum bell and tailhousing with an iron main case,
Thread Starter
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Laughing Gas
Joined: Jan 2006
Posts: 883
Likes: 7
From: New-brunswick,Canada
it's an ole damned fmx to me two now.the main case is not made in aluminum.thanks for the help.Did this trans is good to support hp,torque? I was sure it was a c-4 ,the guy how sold me told me it was a c-4! I bought the complete 351M motor and trans from a big old 78 4 doors and long box.