Offshoreonly.com - Replacement Pistons for an HP500 EFI

The .030 4.500 JE replacement piston for the2001 500efi does not have the dome.I think the # on the bottom of the piston is a 757F part JE# 106906 ?.It has just one valve relief. It is made to be almost 30 down on a stock deck height.Some decks very some. Make sure your guy has a BHJ block tru to square deck the block and can tell ya what the deck height is. ,The top ring land is .360 down which is good for blowers and nos :DThe piston weighs about 720 gr and the pin press fit is a .180 wall about 174 gr.On a 2002 500efi that I have seen had the Manley [Carrillo style ] floating pins

on a 119cc heads piston down .020 come up 8.6cr
Most no cut Chevy heads come up bigger than 119 cc

***Zero decking only gives ya .03 of a CR . I would only take off what is needed to square it up .If ya have to cut it again after zero you will have to run a thicker head gasket. That will be a cometic or the Fel Pro MLS like the cometic the Fel pro MLS is .053. Fel pro doesent make a thicker 1047[+.010]gasket for a 4.500 bore . I just went thru that :(

Most CR figures are made with a fel pro head gasket at .039 compressed height.

The good thing about the replacement JE is it has a regular ring package :D 1/16 1/16 3/ 16 Where the stock piston is metric :( $$$stock is a 2mm,2mm,1.5 oil

Merc.. ring gap recommends .011-.021 on the top and .016-.026 on the 2nd ring.

I ordered a set of speed pros[Federal Mogul]R10451.005 file fit for my motors #. most people pay 147.00 a set.

The other JE piston is there blower piston I think? the # is 182002. it has a .060 dish 11 1/2 cc. and it a little lighter.

On a stock type motor at that bore they recommend piston to wall clear-.0045 then they said on a cold blower motor .0065 clearance .

They [JE] recommended a top ring gap of .030 ..

JE # 1-714-898-9763

Here is the link to some pictures of the JE pistons in my motor
http://www.offshoreonly.com/forums/s...ighlight=strip

Rob :D