Was thinking about it and wondering what would you make more power with a dished piston over a flat given the same compression. The only exception would be that you would need a smaller chamber for the dished to make more power.

I'm trying to build a ford 408 (yea I know), but having problems with too much compression for pump gas with a flat top (more then 12.5:1).

 

What parts are you using? Probe(CHP)

4.00" stroke

You can use 6.125" or 6.250" rods with that desired displacement...go with the shorter rods and keep some skirt length(longevity and oil control)

Link to JE pistons http://www.jepistons.com/pdf/2005-srp5.pdf

What compression do you want? What heads are you using? Chamber size? (61cc is common ford aftermarket) how big of a cam?

Too many unanswered questions to reccomend parts...tell me what you currently have.

As long as the quench is good, you will not notice the difference between a dish or flat-top piston in a street motor.

 

Eagle cast 408 with JE/SRP pistons and 6.25 rods
TEA ported Canfields with 53cc chambers, need to get flowed
ported Vic 5.8 with 75mm TB
XE286 solid roller with 1.7 RRs
1 3/4 or 1 7/8 lt headers

I'm trying to get the DC to ~8:1 or cylinder pressure to as close to 200 cranking psi as possible. I have been told those 2 are probably the limits to pump gas.

 

Thats prettly low DCR, 200 psi of cranking pressure and a DCR of 8 to 1 dont quite jive. With reverse flow cooling more DCR is allowable.


Why a 408? Is it an LT1?


David

 

Looks like a SBF 351W based deal

If you do it right a dish with smaller chamber will make more power because it has a faster burn, but to do it right takes more money and talent.

Most times a flat top with a good flowing and burning chamber will do the best for you.

Bret

 

Its a Ford....please don't shoot now.

If I use a dish pistons I will be using a reverse dome.

 

Send those rods back and exchange for a 6.125" rod then use a 206064 SRP piston zero deck the block. Small head gasket and you will be around 10:1 that's not a very big cam so it will not help much in the DCR.

 

Meant 6.2 on the rod. I was going for something close to 11.5:1 to get my DCR up a little more.

 

Ya can use a 6.250 rods and 2 eyebrow flattops. If ya have anything above a 60CC chamber. Use the Felpro 1011-2 head gasket.Probe has a nice set up for it.
The last one I built made close to 800FWHP with that set up,but I had a nasty Crower mech roller with 1.9 I and 1.8 E rockers and 52CC heads that had over 400CFM flow on the intake.