351 W pistons
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351 W pistons
I have a 351 W eith flat top pistons...i have to lower compression..first option is order some thick head gaskets...or order some dish pistons...both options i can drop comp but with the dish pistons have bettet flame travel and make more HP ?
Re: 351 W pistons
with the dish pistons you can keep some quench with all the benefits thereof
do you have your motor torn down?
what is your current deck clearance- how far are your pistons down the hole
If you can measure all 4 corners
You have to know where you are in order to know which way to go
Are you thinking of GT-40 or Expedition heads (or other) if you have to do a valve job?
are we dealing with early or late- "low" or "high" deck block- what year?
what are your current heads- cc's if you have them
what's your usage?
do you have your motor torn down?
what is your current deck clearance- how far are your pistons down the hole
If you can measure all 4 corners
You have to know where you are in order to know which way to go
Are you thinking of GT-40 or Expedition heads (or other) if you have to do a valve job?
are we dealing with early or late- "low" or "high" deck block- what year?
what are your current heads- cc's if you have them
what's your usage?
Re: 351 W pistons
Are you going to boost this engine or lowering the compression for pump gas? If its a power adder I would buy the dish pistons, If your just lowering the compression for pump gas get the thick gaskets.
Re: 351 W pistons
using thick gaskets and loosing quench is a no win situation
unless you have no quench already
you have to lower compression more if you loose quench at the same time
and the more you lower the compression the more throttle you have to use to make the same power
which makes more heat
answer
lower the compression some more and go around again
fill in the details
unless you have no quench already
you have to lower compression more if you loose quench at the same time
and the more you lower the compression the more throttle you have to use to make the same power
which makes more heat
answer
lower the compression some more and go around again
fill in the details
Re: 351 W pistons
I was trying to say if this was a true max effort style build then pistons are the way to go. If the guy is lowering the compression so he can run pump gas in his dump truck its not worth buying pistons just put thicker gaskets on it.
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Mark O'Neal
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Re: 351 W pistons
Mark's Second Law of Racer Economics……Never spend ten dollars when ten-thousand will do.
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Mark O'Neal
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Re: 351 W pistons
bigfoot wrote:I have a 351 W eith flat top pistons...i have to lower compression..first option is order some thick head gaskets...or order some dish pistons...both options i can drop comp but with the dish pistons have bettet flame travel and make more HP ?
What it is you're trying to do?
Re: 351 W pistons
Thankz for the replys boys....it is for oval track motor which is 9..0 compression rule...2 barrel holley...sounds dish pistons have more quench for mkre HP
Re: 351 W pistons
now you got that right bigfoot
now get a piston with the dish that matches the combustion chamber not some big shallow circle
think how the resulting chambers look to the plug at TDC
just a question- do they let 347's run? Is their a weight rule?
now get a piston with the dish that matches the combustion chamber not some big shallow circle
think how the resulting chambers look to the plug at TDC
just a question- do they let 347's run? Is their a weight rule?
Re: 351 W pistons
Yes there is 347 in the late model class......in our class our cars are 3000 pounds.....do you likr thr 347 more ??? Deffinitly lighter
Re: 351 W pistons
ask Krosser
total vehicle 3000 lbs
lighter motor means you can put ballast where it might do more good
how does that help and is it worth it
on the motor
bore and stroke and heads the same
so do you like short rods or long rods
(cam is different- or should be- slightly, maybe different rockers required to get flow curve to follow the piston down the hole (without going to a longer cam)
so ask around- and ask a good camgrinder which might work best with your application and combination
total vehicle 3000 lbs
lighter motor means you can put ballast where it might do more good
how does that help and is it worth it
on the motor
bore and stroke and heads the same
so do you like short rods or long rods
(cam is different- or should be- slightly, maybe different rockers required to get flow curve to follow the piston down the hole (without going to a longer cam)
so ask around- and ask a good camgrinder which might work best with your application and combination
Re: 351 W pistons
dart Jr steel heads ..1.94 intake valve...60 cc chambers ...right now the motor has flat top pistons..you can get a dish machined in them to match the combustion chamber There is a firm in MO that does good and inexpensive work- someone please post the link - or if you have a mill and rotary table it's not hard
the shape of the dish is important
you want a nice compact combustion chamber and about at same distance from the spark plug tip to all points
In general a good chamber will require less spark lead and will allow more compression (power) for a given fuel
The open big block chrysler is about a bad as it gets
followed by those early BB Chrysler and sbc heads with the plug low on the side of the chamber with no plug cooling
I used to mill the old school heavy TRW/ Sealed Power pistons
look at the classic TRW D cup "turbo" piston as a model for a wedge chevy
later combustion chambers like Vortec are slightly different- also the plug tip has been relocated and more away from the wall
I'll look up the dart jr heads later
Krooser?
the shape of the dish is important
you want a nice compact combustion chamber and about at same distance from the spark plug tip to all points
In general a good chamber will require less spark lead and will allow more compression (power) for a given fuel
The open big block chrysler is about a bad as it gets
followed by those early BB Chrysler and sbc heads with the plug low on the side of the chamber with no plug cooling
I used to mill the old school heavy TRW/ Sealed Power pistons
look at the classic TRW D cup "turbo" piston as a model for a wedge chevy
later combustion chambers like Vortec are slightly different- also the plug tip has been relocated and more away from the wall
I'll look up the dart jr heads later
Krooser?
Re: 351 W pistons
That is great info..thanks...is that machine shop in the St Louis area that mills the piston tops ??