![SEARCH](http://www.mustangworks.com/images/search.png)
![The Mustang Works](http://www.mustangworks.com/images/mw_footer_logo.gif)
© Copyright 1995 thru 2008 - The Mustang Works™. All Rights Reserved.
MustangWorks.com is designed and hosted by Aero3 Media.
MustangWorks.com is designed and hosted by Aero3 Media.
![]() |
#1 |
CAR9FAN
Join Date: Mar 2004
Location: m.d
Posts: 103
|
![]() Hello. I recendly had to replace my short block do to a cracked CID. I bought a New shotr block from Heartland Engine builders. would have done the rebuild myself but no good block and got my New short block for a fair price, My concern is he said the motor would have 10.1 Compresstion with my parts but when i put the motor back togather the pistons was not dome pistins like i had before they just had really deep fly cuts in them, So i called him and he asured me that the motor would have 10.1 comp.I know theres no way to tell now what comp. i have,The track is closed for the season, Can someone tell me how much HP i would lose if i did go from 10.5.1 to 9.5.1? Or is there a flat top piston that could make 10.5.1 comp. with my 60 cc edelbrock RPM heads. The motor feels good but cant tell on the street, If you want to see what all i have in my motor go to this link. Thanks for any Advise, Ronnie MY PAGE
__________________
MY HOME PAGE |
![]() |
![]() |
![]() |
#2 |
Moderator
Join Date: Aug 2000
Location: Milan, OH
Posts: 2,699
|
![]() At 60cc you're not going to get to 10.5:1 with flat tops and big valve reliefs. Even 9.5 is going to be tough; its looking more like 9.2-9.4:1 depending on where the piston is relative to the deck (http://crt-performance.com/compression.htm). Generally speaking, a full point of compression (say from 9.5 to 10.5) is worth about 15% net power at the crank.
__________________
Jeff Chambers 1990 Mustang GT 10.032 Seconds / 137.5 MPH 14-time Street Warrior World Record Setter CRT Performance 2001 Tropic Green Mustang GT - 12.181 / 113.2 MPH 2002 Ford F-250 Crew Cab 7.3l Power Stroke - 17.41@77.2 "There's nothing boring about a small block automatic shifting gears at 9400 rpm!" |
![]() |
![]() |
![]() |
#3 |
Registered Member
Join Date: Nov 1998
Location: Houston, Tx.
Posts: 3,887
|
![]() When I ran 351W heads, 59.5 cc's, pistons down 0-.005" in the bore with 2.7cc valve reliefs and .049" compressed gasket we figured 9.5/1 CR. That's with 4.030" bore and a 302 crank. Hope that helps a little.
Rev
__________________
'66 Coupe, 306, 350-375 HP, C-4, 13.07 e.t., 104.8 mph, 1/4 mi. O.B.C. #2 '66 coupe |
![]() |
![]() |
![]() |
#4 |
CAR9FAN
Join Date: Mar 2004
Location: m.d
Posts: 103
|
![]() Thanks for the reply, I figured you was going to say that!!! Well i guest i will have to wait and see what the car does when the track opens, Thanks Again, Ronnie
__________________
MY HOME PAGE |
![]() |
![]() |
![]() |
#5 | |
CAR9FAN
Join Date: Mar 2004
Location: m.d
Posts: 103
|
![]() Quote:
__________________
MY HOME PAGE |
|
![]() |
![]() |
![]() |
#6 | |
Registered Member
Join Date: Apr 1999
Location: Cincinnati,OH
Posts: 1,511
|
![]() Quote:
__________________
89GT,Pro-Bullet 306, H/C/I and a bunch of other stuff. *Sold* 00GT, Vortech S-Trim, Steeda Boost Pipe, C&L intake, Mac off-road H-pipe, Flowmasters, B&M Ripper shifter, Eibach Sportline springs, Koni Struts/shocks, MM full length subframe connectors, Cobra brakes, 3.73's. My Car Domain Page |
|
![]() |
![]() |
![]() |
#7 |
Moderator
Join Date: Aug 2000
Location: Milan, OH
Posts: 2,699
|
![]() You're right, I must have been on dope when I posted that. Generally speaking its 3-5% for a full point of compression. Thanks for correcting me! All I had to do was read the page I referenced!
__________________
Jeff Chambers 1990 Mustang GT 10.032 Seconds / 137.5 MPH 14-time Street Warrior World Record Setter CRT Performance 2001 Tropic Green Mustang GT - 12.181 / 113.2 MPH 2002 Ford F-250 Crew Cab 7.3l Power Stroke - 17.41@77.2 "There's nothing boring about a small block automatic shifting gears at 9400 rpm!" |
![]() |
![]() |
![]() |
#8 | |
Registered Member
Join Date: Apr 1999
Location: Cincinnati,OH
Posts: 1,511
|
![]() Quote:
__________________
89GT,Pro-Bullet 306, H/C/I and a bunch of other stuff. *Sold* 00GT, Vortech S-Trim, Steeda Boost Pipe, C&L intake, Mac off-road H-pipe, Flowmasters, B&M Ripper shifter, Eibach Sportline springs, Koni Struts/shocks, MM full length subframe connectors, Cobra brakes, 3.73's. My Car Domain Page |
|
![]() |
![]() |
![]() |
#9 |
Moderator
Join Date: Aug 2000
Location: Milan, OH
Posts: 2,699
|
![]() I actually got my P-heads down to less than 42cc's! I've got my TW heads down to less than 40cc right now and looking for more. The SBF responds like gangbusters to increased compression.
__________________
Jeff Chambers 1990 Mustang GT 10.032 Seconds / 137.5 MPH 14-time Street Warrior World Record Setter CRT Performance 2001 Tropic Green Mustang GT - 12.181 / 113.2 MPH 2002 Ford F-250 Crew Cab 7.3l Power Stroke - 17.41@77.2 "There's nothing boring about a small block automatic shifting gears at 9400 rpm!" |
![]() |
![]() |
![]() |
#10 | |
Rat Killer
Join Date: Aug 2002
Location: Cold ass Ohio
Posts: 1,143
|
![]() Quote:
AMEN brother!!! Even on pump gas. ![]()
__________________
d-Con Racing "Nothing fancy, just 347 inches of RAT POISON!" MICE need not apply..... ![]() |
|
![]() |
![]() |
![]() |
#11 | |
CAR9FAN
Join Date: Mar 2004
Location: m.d
Posts: 103
|
![]() Quote:
__________________
MY HOME PAGE |
|
![]() |
![]() |
![]() |
#12 |
Registered Member
Join Date: Apr 1999
Location: Cincinnati,OH
Posts: 1,511
|
![]() No what we're saying is if you did drop your CR from 10.5 to 9.5 on a 400hp motor you would lose about 15hp or so. The easiest way to make that back up it to take the heads and have them milled. Infact if you have enough piston to valve clearance you could take them down quite a bit and get your CR above 10.5:1.
__________________
89GT,Pro-Bullet 306, H/C/I and a bunch of other stuff. *Sold* 00GT, Vortech S-Trim, Steeda Boost Pipe, C&L intake, Mac off-road H-pipe, Flowmasters, B&M Ripper shifter, Eibach Sportline springs, Koni Struts/shocks, MM full length subframe connectors, Cobra brakes, 3.73's. My Car Domain Page |
![]() |
![]() |
![]() |
#13 |
CAR9FAN
Join Date: Mar 2004
Location: m.d
Posts: 103
|
![]() Thanks Alot thats good news, The block and the heads have never beem milled so i think iam going to check on getting the heads milled down, Thanks Again, CAR9FAN
__________________
MY HOME PAGE |
![]() |
![]() |
![]() |
#14 |
Registered Member
Join Date: Sep 1998
Location: Oviedo, FL
Posts: 992
|
![]() One more thing, when you have the heads milled, check the gasket alignment where the intake meets the cylinder heads. If the heads are milled too much the intake won't match up correctly. You then have to have the intake milled to match the cylinder heads. If not the intake gaskets will leak vacume/oil/coolant, any or all.
__________________
"Support our Troops" Dave 1968 Cougar 2004 Thunderbird 2007 F150 Harley-Davidson, SuperCrew 1986 LTD 1997 Ranger 1992 Honda Civic |
![]() |
![]() |
![]() |
#15 |
CAR9FAN
Join Date: Mar 2004
Location: m.d
Posts: 103
|
![]() Ok Thanks For The Info. Car9fan
__________________
MY HOME PAGE |
![]() |
![]() |
![]() |
#16 |
Registered Member
Join Date: Sep 2002
Location: cent.wis
Posts: 203
|
![]() Don't forget about your pushord lengths. I think they will change too, will milling.
|
![]() |
![]() |
![]() |
#17 |
CAR9FAN
Join Date: Mar 2004
Location: m.d
Posts: 103
|
![]() Thanks For The Info, Car9fan
__________________
MY HOME PAGE |
![]() |
![]() |
![]() |
|
|