What S.E pistons do I use?

[dennish]

Taking my '07 SG in for head porting, cylinder boring and TW 55 cams. I know I need 10.5 cr. Which is the S.E. piston to use? The only one's I see in the S.E. catalog for an '07 are for 103+ heads. The other forged high compression pistons fit '99 thru '06. Is there no high compression pistons for my build in the S.E. line? Thanks.

[Bill Clem]

The 103 ci pistons are the same as the previous 95 ci, the difference is the stroke in your '07. The cylinders are the same and are identical to the 88 ci cylinders.

07 has 4.375" stroke making the 3.75" cylinders a total displacement of 96 ci. Going to 3.875 " bore makes the 07 a 103 ci engine.

Previous years had 4.00" stroke making the 3.75 bores a total of 88 ci and 3.875" cylinders a 95 ci engine.

BC

[Gulfstream]

I believe the 103" pistons have a shorter skirt to eliminate interference because of the longer stroke...not the same as the 95" pistons.

[Bill Clem]

YES! You are absolutely correct. So it would have to be the SE 103 'stroker' pistons. Yep, that's right!

Thanks,
BC

[dennish]

Thanks. Yes, I know the 95" and the 103" pistons are the same. My confusion with the catalog is there are two high compression forged pistons sets for the 103"/95" application. One set is for the 103+ heads and shows an '07 fitment, the other set is for stock heads '99 - '06. Why does the stock head fitment only goes up to '06? Just a typo? I have read where the '07 connecting rods are a tad shorter than previous years. Is this an issue?

[nw_guy4_fun]

I went 107 just because there are issues with the rods being short (yes they are... stock pistons can be up to .025 down in the hole) and I wasn't about to have to screw with cutting the barrels to get the quench right. Revolution performance compensated the pistons and I ended up with a decent -.005 deck. With 83cc heads there is a lot of compression in this motor. Why are you wanting to run domes?
So that HC piston for the stock head 103" will work fine but down in the hole the quench situation would all but kill the incentive to go with HC pistons and the ping potential goes up significantly.
So my advice use stock flatops and zero deck them with a .030 head gasket and CC the heads to get an honest 10.5/1 CR, or use the RP 107" kit with flatops and do the same.

[dennish]

Thanks nw_guy. I will go that route. I know I'm being a little foolish here but I intend to end up with a 107" w/ R&R heads etc.... next year. I cannot bear the thought of riding a stock 96" this summer. Our dealer is offering a 50% off labor for the month of March for some customers. Since they do their own porting and cylinder boring I figured at 50% off labor I could at least get something that moves at a reasonable price.

[dennish]

The s.e. catalog offers big bore high comp pistons (10.5:1) for the 103+ heads. So, without starting a thread concerning how ethical the MOCO is in their advertising, I gotta believe when they say 10.5:1 with the 103+ heads they mean it.

I plan on getting the R&R heads next year. From what I read here, for close to the same amount the the R&R heads would be a better choice than the s.e. heads.

[nw_guy4_fun]

The 103+ pistons will not work with the stock or R&R style chamber. It may be close to that CR with those heads.
The 103+ heads are not to be even slightly compared to the R&R heads very different.
The flattop piston (SE 103" stocker) would be my choice then mill the stock heads and maybe a cheap port job BigBoyz etc. Then do the rest later.
If it is Latus I would guess they push Baisley heads and the 251 cams

[route66paul]

The domed type pistons do not work as flattops or the dished pistons. It has something to do with the proper burning of fuel. You might look into these dished pistons, they show some promise.