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Discussion Starter #1
Looking at the edelbrock performer 5.0 heads. They have 60cc chambers. I was wondering if this will drop the compression too much on my 289 with the stock pistions. If I remember correctly the chambers on the 289 heads are smaller. Just need some advice, shooping for heads.

Matt
66 289 coupe
98 GT coupe
 

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Assuming a std. bore and zero deck hieght, you'll have about 8.4:1 if you have a "C" code engine. The cylinder volume is 592 cc's, piston dish = about 13 cc's, gasket volume = about 7 cc's and head = 60 cc's. 592+13+7+60=672 cc's / 13+7+60=c.r. of 8.4:1.

Of course an over bore and if you don't have a zero deck hieght and the piston is down the bore a little bit, these will also have an effect on the c.r..

Tom
You can do anything you want to......ONCE!
aka "my 66 coupe"
http://albums.photopoint.com/j/View?u=1575517&a=11977890&p=44194856.jpg

Hale Boppe comet shot off my roof. See you can use 100 iso at night with no flash!
 

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Matt,

It doesn't really matter, as chances are you will have to replace your pistons to use new heads anyway. If your current pistons don't have valve reliefs (and if they are stock they don't), you will not be able to use them with aftermarket heads that have larger valves. The exhaust valve will hit the piston just before it gets to TDC during the exhaust stroke.

Stock C-Code 289 Piston

http://www.blueriver.net/~finite/DSC19502.JPG

Your choices are to get valve reliefs fly cut in your piston, or replace your pistons. If you replace your pistons, might I recommend KB116's which will give you around 10:1 compression (just under I would think) with 60 cc chamber heads. You'll need a machine shop to press your wrist pins out and your new ones in. I would suggest having them replace your rod bolts with quality ARP bolts while they have them. The ends will need to be resized when this is done. Oh and you have to hone your block if you replace your rings to get them to seat right. And you might as well replace your cam and lifters to take advantage of the new heads. Course it's always a good idea to replace your timing chain when you replace your cam. You'll want to go to roller rockers on those new heads so your old valve covers won't fit. And you have to get the correct push rods. While you have the pan off, you should consider replacing your oil pump. In fact replace your water pump and fuel pump too. I could go on all day long.

Oh to heck with it. Just take a look at my webpage and see what shopping for cylinder heads got me into!

http://www.blueriver.net/~finite/mopower.htm

Good luck!

Phil


'65 Convertible (with many mods.)
http://www.blueriver.net/~finite/Pony.htm
 

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Discussion Starter #4
Thanks for the advice, I have a cam to put in as well as timing gear ,lifters, and new pushrods. I was considering rollerrockers. Also in Jegs it said that if I get the 1.90/1.60 int/exh that this will work with stock pistons. Also will roller rockers bolt up to the edelbrock heads without machine work? I heard that if I used the stock heads they would have to be machined to accept roller rockers. What kind of hp gain should I expect with the edelbrock heads, roller rockers, and the mild cam that I have yet to put in.

Matt
66 289 coupe
98 GT coupe
 

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My AFR's were bolt on too. Bolt em on and then take em off and get new pistons. I'm telling you that just because edlebrock say's its so don't make it so. I can't help you on the rocker arms. I was planning on roller rockers all along and that's what the heads came set up for.

Phil

Did I mention the valves are going to hit your pistons? They are bolt on for any stock SBF with valve reliefs. See my picture above for what your pistons look like. Best I could tell Mustangs started getting valve reliefs in 1977. The big valves will overhang onto the flat top (unrelieved) part of the piston and that's were the exhaust valve is going to hit it. Right at the edge of the little dish.



'65 Convertible (with many mods.)
http://www.blueriver.net/~finite/Pony.htm
 

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The early "C" code pistons did not have valve reliefs, but in May of 65 they started changing over to 4 valve reliefs. At least that's what Bob Mannel's book says.

65 FB "J" 302 lots of mods. 94 GT K&N only.
http://albums.photopoint.com/j/view?u=1590489&a=12113030&p=43871256.jpg
 
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