So I plan on getting the the 340-416 stroker kit from summitracing and thought I had it pegged. But another question came up.

I want the engine to have at least 10:1 or more compression, but not more than 11:1

Im going to get the head CC'd and Im thinking to make it around a 64cc.

One kit SCAT Engine Components 1-98012BI has a piston thats a forged flat top with two valve reliefs. *What is the benifit of this?

The SCAT Engine Components 1-98013BI has a forged "dish" with D shaped cup.

~what kit should I buy??


THANKS GUYS!!

 

What is the planned end use ? Fuel ?

 

The flat to is going to get you 11.3 ish
The dish is going to get you 9.7 ish

Best bet would be to cc the head and proceed with either of the following:

Have the machinest do the math and let the piston stick out .005 + or - depending on the math with kit 1.

Or have him run the deck machine at half seed to get a finer finish for an mls gasket to cut the compressed head gasket thickness in half to get you closer on 10:1.

I think scat uses .040 as compressed head gasket thickness with a 4.060 bore. So stick that in an on line calculator to do some numbers.

I have been less than happy with gas these days and personally like the ability to take out a little timing and run a little less octane for a street cruiser.

If this is all go motor.. you need to answer TV Lynns question as to what fuel you have access to.

 

@TVLynn, I plan on running premium, usually from speedway and its 93 octane. When ever I get gas from my local Sunoco my car doesnt run as well.

Planned use is street/woodward dream cruise! Also an occasional track trip(twice a year) as my father lives 5 minutes from a local drag way.

@PK1, Thanks for the in depth response, On monday I am going up to try and talk to a new company/machinest.

Now I have a slightly better idea what I need

Thanks guys!

 

yes, good info. i am in need of new pistons as well

 

@PK1 or TVLynn

So in your opion, what is the better compression ratio to go with while running on 93 octane??

Some people tell me to stay at 10:1 compression, but others say you can run almost 12:1 on 93 with out that bad "PING" I find 12:1 is hard to belive!

OH WHAT TO BUY!!!!

 

You could probably get away with 12 to 1 ONLY if you go to aluminum heads and pay careful attention to assembly with the cyl quench area !!! Personally I would stick with the 9.7 and tune from there

 

Awesome thats what I needed to hear! Thanks alot

I will let you guys know how the tear down goes!

 

Very important question...
What Camshaft are you planning on running ?
The Camshaft timing events will determine wheter you will DETONATE the 92 Octane at 10.5:1, or conversely run fine at 12:1 "static" Compression Ratio on 92.

You must also bear in mind...
the differences in Flamefront propagation, and Ignition Timing, between a Flat Top Piston and a D-Cup.

Quench area is the SAME on a sb Mopar between a D-cup or Flat Top Piston, NO DIFFERENCE, because the "quench" portion is Flat, same as the Flat top,
rather,
just the Flamefront Propagation changes.

 

I decided that I am going with the Dished style piston, I dont believe I need high compression for what I am using the car for.

Camshaft is still unknown, I have another thread out there that many ppl have responded on. I want to convert to a hydraulic roller system so I do not have to re adjust once a year.
Thinking around a 500 lift tho with around 280 duration

I did not know that the quench area is the same for flat/d cup pistons..Thank you for that!

~Sean