Heads

[al383]

I have a 69 superbee with a383 bored 30 overthe bottom end is done,Now i need heads.Ijust talked to a rep. at edelbrock he asked about the cc that the pistons are for 84 or 88 I dont know.Pistons are 12.5-1, can some one help please thanks.

 

[Deleted member 214]

Others can give more info but the actual compression ratio varies according to a lot of factors. Has the motor been decked? The height of the piston in the hole (below the deck at Top Dead Center, above, right at deck height) will affect the compression ration. The thickness of your head gasket will also change your CR.

 

[67 B-body]

There are some very good calculators available online that you can use to figure it all out. As mentioned above, you will need to do your homework first. Get the dimension from the top of the piston to the top of the deck " not measured from the top of the dome". Sometimes they are down .050" in the hole, other times they are .020" or less depending if the deck has been cut down. Plug in .055" for a start. Also get the dia of your head gasket and its thickness,,, you'll need that too. Your piston are going to be dished, flat, domed, valve relief cut, or a combination of these. The important thing is to know the pistons volume, it's going to be a "+ or a -" amount. My domed piston with a valve trough relief has 14cc. Now you need to know the heads chamber size "CC". Plug them all in with the Bore and Stroke and presto!
Hope it helps...

 

[al383]

no i dont think the block was decked,but thanks for the response

 

[al383]

How do I find out the measurement from top of piston to top of deck when the heads are on? Deck has not been cut. I don't know the thickness of the head gasket yet. My pistons are J & E domed, fly cut 30 thousandeths because of the lift of the cam. Thanks for the help, that's alot of info. I'll try to make it work for me.

 

[Cranky]

How do I find out the measurement from top of piston to top of deck when the heads are on? Deck has not been cut. I don't know the thickness of the head gasket yet. My pistons are J & E domed, fly cut 30 thousandeths because of the lift of the cam. Thanks for the help, that's alot of info. I'll try to make it work for me.

You don't but if you know the part number of the pistons, you can go to JE's site to look up what the compression height is or call them and ask but it's always best to get an actual measurement. Also, the dome shape may not fit the Eddy heads combustion chamber. One or the other or both may be able to tell you. Gasket recommendation for alloy heads is the 1009 in most cases. Also, pistons are advertised as the 'most' compression they will provide when you do all you can to achieve it like smallest CC heads, decking the block etc. When buying pistons, always buy according to the compression height.

 

[al383]

Thanks Cranky Ill ck. on that part no. tommorrow.Also thanks for other info.

 

[67 B-body]

You don't but if you know the part number of the pistons, you can go to JE's site to look up what the compression height is or call them and ask but it's always best to get an actual measurement. Also, the dome shape may not fit the Eddy heads combustion chamber. One or the other or both may be able to tell you. Gasket recommendation for alloy heads is the 1009 in most cases. Also, pistons are advertised as the 'most' compression they will provide when you do all you can to achieve it like smallest CC heads, decking the block etc. When buying pistons, always buy according to the compression height.

I was also concerned with piston dome shape using EDDY VICTOR heads. Turns out that even though the piston I'm using is designed for the "D" shaped cumb chamber, it makes no differance. I have the newer L225f Forged pistons, and I found no interferance issues. I even found an artical from Mopar magazine that has the EXACT pistons and rod combo as what I used with an INDY heart sape closed chamber head design like the VICTORS. Not saying you shouldn't do your homework, just passing my findings out.
Good luck!

 

[al383]

Im going to need a lot of luck to do this.There is just so much info you need,Ishould have done this when i built the engine,But founds didnt allow it,Im paying for it now