Going to flat top pistons?

1

1973mach1

Member

May 19, 2003

457

0

16

PA

Jan 3, 2004

#1

• Jan 3, 2004

• #1

IM going to be pulling my 351c 2v soon, its a 72' engine I was wondering if adding flat top pistons 9.1 to 1 compression would make much difference over the dished pistons they used in 72' and 73', 8.6 to 1 compression I think they had? How much compression do I want for an street engine like this?

Thanks,
Jim

 

C.Harris

Da Boss

Founding Member

Dec 20, 1998

1,850

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0

Jan 4, 2004

#2

• Jan 4, 2004

• #2

I have no problem running 10:1 compression on the street with pump gas (93) with my '71

 

F

Fostang

Founding Member

May 8, 2002

1,400

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36

Stockton, Ca

Jan 4, 2004

#3

• Jan 4, 2004

• #3

I say at least 10.5 and some hardned valve seats. Make it worth your while.

My buddy will be running 11.5 on pump gas on his Chebby.

 

jcp123

New Member

Nov 1, 2003

408

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0

Tyler, TX

Jan 4, 2004

#4

• Jan 4, 2004

• #4

that depends on some stuff: the octane of your local premium, how big a cam you have (since a big one can sometimes effectively lower your static compression)...off the top of my head i'd say 10:1

 

Route666

Active Member

Aug 16, 2003

1,652

6

39

Brisbane, Australia

Jan 4, 2004

#5

• Jan 4, 2004

• #5

I'd say 10.5

 

6

'69Stang

Founding Member

Sep 28, 1999

1,130

2

38

Metro Detroit

Jan 5, 2004

#6

• Jan 5, 2004

• #6

If you have the 2v heads the flat top pistons (+2 to 4cc’s) should net you just around 10:1, and that should be fine. If you want more compression you will have to mill the heads (and intake manifold). If you have 10.5:1+ compression I’d run a minimum of 92 octane.

If you had quench heads you could run more, but I’d stick to 10.5:1 or less with those heads.