P 51 spark plugs
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P 51 spark plugs
What plug should I use with P51 heads? heads as out of the box
flat top pistons .010 in the hole solid roller and a 1400 sv1 carb
14.5 to 1 comp ratio 545 cid
flat top pistons .010 in the hole solid roller and a 1400 sv1 carb
14.5 to 1 comp ratio 545 cid
Larry Williams- Posts : 884
Join date : 2009-08-08
Age : 79
Location : Wallacetown Ontario
Re: P 51 spark plugs
Larry Williams wrote:What plug should I use with P51 heads? heads as out of the box
flat top pistons .010 in the hole solid roller and a 1400 sv1 carb
14.5 to 1 comp ratio 545 cid
How is this engine to be used and does it have a closed exhaust system...?
I would probably use a #3910 Autolite with that compression ratio.
Re: P 51 spark plugs
a drag only engine with 2" headers
Larry Williams- Posts : 884
Join date : 2009-08-08
Age : 79
Location : Wallacetown Ontario
Re: P 51 spark plugs
have a 514. 15:1 compression. p51 heads, qtf 1250 worked over. use autolite AR3933 plus, no problems. bracket car.
Rickytx630- Posts : 100
Join date : 2016-01-18
Re: P 51 spark plugs
Rickytx630 wrote:have a 514. 15:1 compression. p51 heads, qtf 1250 worked over. use autolite AR3933 plus, no problems. bracket car.
I have lots of those ty
Larry Williams- Posts : 884
Join date : 2009-08-08
Age : 79
Location : Wallacetown Ontario
Re: P 51 spark plugs
A 514 at 15/1 will have a domed piston ... not a flat-top.
One plug is an extended tip and the other is not.
It will be a personal choice.
One plug is an extended tip and the other is not.
It will be a personal choice.
Re: P 51 spark plugs
rmcomprandy wrote:A 514 at 15/1 will have a domed piston ... not a flat-top.
One plug is an extended tip and the other is not.
It will be a personal choice.
is the 3910 an extended tip? Would it be ok to break in the motor with 3932/3933 then go with the 3910x ?
Larry Williams- Posts : 884
Join date : 2009-08-08
Age : 79
Location : Wallacetown Ontario
Re: P 51 spark plugs
Larry Williams wrote:rmcomprandy wrote:A 514 at 15/1 will have a domed piston ... not a flat-top.
One plug is an extended tip and the other is not.
It will be a personal choice.
is the 3910 an extended tip?
Yes ... I personally would use a hotter "street type" plug for initial running. Something like a 3924.
Re: P 51 spark plugs
rmcomprandy wrote:Larry Williams wrote:rmcomprandy wrote:A 514 at 15/1 will have a domed piston ... not a flat-top.
One plug is an extended tip and the other is not.
It will be a personal choice.
is the 3910 an extended tip?
Yes ... I personally would use a hotter "street type" plug for initial running. Something like a 3924.
I have a few sets of those too. I have to order the 3910's thanks for the info
Larry Williams- Posts : 884
Join date : 2009-08-08
Age : 79
Location : Wallacetown Ontario
Re: P 51 spark plugs
rmcomprandy wrote:A 514 at 15/1 will have a domed piston ... not a flat-top.
One plug is an extended tip and the other is not.
It will be a personal choice.
JE flat tops. no domes in my motors.
Rickytx630- Posts : 100
Join date : 2016-01-18
Re: P 51 spark plugs
Rickytx630 wrote:rmcomprandy wrote:A 514 at 15/1 will have a domed piston ... not a flat-top.
One plug is an extended tip and the other is not.
It will be a personal choice.
JE flat tops. no domes in my motors.
A 514 with a flat-top piston at "0" deck, #1018 head gasket and a 70cc combustion chamber is about 13.4/1 compression ratio.
The heads would need to be milled near 60 cc's to be at 15/1 compression.
Your personal choice is to use non-extended tip spark plugs; there is not an actual NEED to do so.
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