|
|
03-31-2025, 06:04 PM
|
#1 |
|
Member
Join Date: Mar 2006
Location: California
Posts: 186
Likes: 3
Liked 179 Times in 52 Posts
|
139 hp 302 ford help
Need help with the deck height , NHRA list a 302 at .047 Gasket ,and the deck height at .0005 is this correct
__________________
John Ancona 717 STK / SS |
|
|
|
03-31-2025, 06:58 PM
|
#2 |
|
VIP Member
Join Date: Dec 2001
Location: Arkansas - In the middle of everything.
Posts: 1,999
Likes: 63
Liked 772 Times in 192 Posts
|
Re: 139 hp 302 ford help
Yes.
__________________
|
|
|
|
| Liked |
|
03-31-2025, 07:36 PM
|
#3 | |
|
Member
Join Date: Mar 2006
Location: California
Posts: 186
Likes: 3
Liked 179 Times in 52 Posts
|
Re: 139 hp 302 ford help
Quote:
so the piston is five tenths above the deck
__________________
John Ancona 717 STK / SS Last edited by john ancona; 03-31-2025 at 07:47 PM. |
|
|
|
|
|
03-31-2025, 11:16 PM
|
#4 |
|
Senior Member
Join Date: Oct 2006
Posts: 613
Likes: 306
Liked 684 Times in 195 Posts
|
Re: 139 hp 302 ford help
Negative vs. Positive Clearance:
Negative clearance means the piston protrudes slightly from the deck surface, while positive clearance means the piston sits a bit inside the cylinder bore. The .0005 on the chart appears to be a positive number so the piston should be below the deck. I assume if it’s assembled .0005 above a .048 gasket gets you back to correct deck clearance.
__________________
Mike 7570 A/SA Last edited by Mike Gray; 03-31-2025 at 11:29 PM. |
|
|
|
| Liked |
|
04-01-2025, 12:49 PM
|
#5 | |
|
VIP Member
Join Date: Dec 2001
Location: Arkansas - In the middle of everything.
Posts: 1,999
Likes: 63
Liked 772 Times in 192 Posts
|
Re: 139 hp 302 ford help
Quote:
__________________
|
|
|
|
|
| Liked |
|
04-01-2025, 07:34 PM
|
#6 |
|
VIP Member
Join Date: Jun 2009
Location: Boulder City, Nevada 89005
Posts: 2,719
Likes: 2,760
Liked 2,425 Times in 687 Posts
|
Re: 139 hp 302 ford help
Basically, a Zero Deck Piston for all practical purposes.
__________________
John Irving 741 Stock 741 Super Stock |
|
|
|
| Liked |
|
04-03-2025, 07:57 AM
|
#7 |
|
Live Reporter
Join Date: Oct 2004
Location: Hickory, Ky
Posts: 10,611
Likes: 1,896
Liked 10,647 Times in 2,207 Posts
|
Re: 139 hp 302 ford help
For longevity of the block it might be best to start with a deck clearance of .010 to .015 if gaskets are available to bring the number to .048. If is easier to skim cut the block in the future than to shorten the rods or de-stroke the crank to get to the legal numbers.
|
|
|
|
|
04-03-2025, 12:32 PM
|
#8 |
|
Junior Member
Join Date: Jan 2011
Posts: 87
Likes: 18
Liked 154 Times in 34 Posts
|
Re: 139 hp 302 ford help
The early 302 blocks (68-72) deck height are about .020 lower than the 73 and up 302 blocks so with a early block you're close to 0 deck height and with a later block you're about .020 in the hole. Brian Seaberg 627
|
|
|
|
| Liked |
|
04-06-2025, 10:36 PM
|
#9 |
|
VIP Member
Join Date: Jun 2009
Location: Boulder City, Nevada 89005
Posts: 2,719
Likes: 2,760
Liked 2,425 Times in 687 Posts
|
Re: 139 hp 302 ford help
Cometic has always made us whatever thickness gaskets we needed
to get deck and gasket height whatever we have need to be legal.
__________________
John Irving 741 Stock 741 Super Stock |
|
|
|
 |
|
|
Linear Mode
