compression ratio with flat top pistons in 430

[edselman]

I have installed a set of the EGGE pistons[flat top] in the 430 I have. I was trying to deterimine what the compression ratio would be if I used a set of steel head gaskets. I had the heads reworked and had about .005 removed. I know it will be less than the 10.5 to 1. I was told by Egge that I would lose .5 to 1. Would appreciate your thoughts. Tom

[KULTULZ]

The pistons from EGGE are incorrect. Here is a post from the Old Forum describing their useage-

Migginsbros gives us warning where not to buy:

“Seems that it is not easy to get pistons for the 430 engine. We own a Mercury Monterey from 59 with 383 engine. We get a matching 430 crank and some old 430 pistons as a sample. At Kanter we ask for the pistons used in the original MEL 10,5 : 1 version. You must be use 4 pistons specially for the right and 4 for the left bank. Due to the notice at the Kanter catalog it seems that they know about the specifications of the 383 and 430 engine from 58-60. We ordered a set of pistons and will be shocked getting 8 flat top pistons. We called them that these pistons can not give us a compression ratio of 10.5:1 It must be a joke that the technical/salesman is shure that they will work and only have a little less compression. We build in both pistons to figure out the combustion camber (which is in block) so we can get the compression ratio of both pistons. The original piston give us a 10.7 : 1 compression ratio. The Kanter pistons give us a 8.3 : 1 compression ratio. That's not that what we want if we rebuild a 430 engine. Hoping for a second chance we ordered a 10.5 : 1 piston kit as a original replacement for our 430 at Mad-Dog-Racing (same as ERW- Parts). But what we get are the same pistons as Kanter shipped us. We have many telephone calls and mailing with them but the sad truth is that they don't understand what went wrong.”

The pistons will negate the MEL Combustion Chamber size. If one wants to increase CR, the block deck would have to be cut, not the head surface.

[Theo]

I doubt if he would compensate for such a big loss of compression. I would rather go for custom made pistons from JR Pistons, Ross or similar than milling my parts' a## off. You would have to mill a lot I guess Maybe too much to leave some healthy beaf.
I could be wrong though.

[reijerlincoln]

Tom, did EGGE have both the flat top and the OEM pop-up design on offer for the 430? I'm asking because I ordered a set of 462 pistons in 2007 and they were the pop-up design. I'm wondering what's the difference between what they have on offer for the 430 and the 462.