HELP!! 70cc or 64cc combustion chambers????

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Old 12-09-2006, 11:51 PM
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Default HELP!! 70cc or 64cc combustion chambers????

78' Z28
I have a 355ci
performer cam
performer manifold
Holley 600
holley fuel pump

This will be my street/work car

I am getting a new set of heads Edelbrock's performer series..... should I get 70cc or 64cc combustion chambers ???
I just want it to run well, the best performance, NOT RACING

[IMG]local://upfiles/5238/A241FF3FF3F2485C9FC6A45C308B3085.jpg[/IMG]
 
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Old 12-10-2006, 12:55 AM
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Default RE: HELP!! 70cc or 64cc combustion chambers????

What size pistons do you have? It depends on what compression ratio you want. If it's just stock over sized pistons, you can run it on pump gas.
 
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Old 12-10-2006, 01:45 AM
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Default RE: HELP!! 70cc or 64cc combustion chambers????

stock flat top pistons

and yes I want to run it on pump gas
 
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Old 12-10-2006, 02:04 AM
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Default RE: HELP!! 70cc or 64cc combustion chambers????

Did you deck the block, and what are your cam specs(lift mainly)?
 
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Old 12-10-2006, 02:25 AM
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Default RE: HELP!! 70cc or 64cc combustion chambers????

Edelbrock Camshaft #2102 Performer Plus
http://www.edelbrock.com/automotive/cams_chevy.html#rpm

I bought the car recently, he told me it was recently rebuilt.....(I only paid $1000 for it) bored .030 I am assuming stock flat top pistons
but I have never been able to get it to run well, till I put a vac gauge on it, and the valve guides are shot, soooooo

I am getting a new set of edelbrock performer heads but I want to "make sure" I get it right the first time..

Thanks for taking the time



[IMG]local://upfiles/5238/88A499BE41134AAEAD4E864C33B40475.jpg[/IMG]
 
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Old 12-10-2006, 03:13 AM
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Default RE: HELP!! 70cc or 64cc combustion chambers????

$1000 for the car in the picture damn..nice. I think to get a real good number you need to find out what is in the engine as far as pistons if the engine block has been decked you are only talking about a 6 cc difference in the 64 vrs 70cc heads the extra set of eyebrow reliefs in a stock piston will give you close to that volume. You could push yourself over 10.5 :1 which could put you into the premium fuel catagory. Naturally the 70cc is the safest bet but I would get better specs from the previous owner or take the heads off and check what you and then we can work the numbers.
 
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Old 12-10-2006, 04:18 AM
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Default RE: HELP!! 70cc or 64cc combustion chambers????

I haven't done any cosmetic work other than a used chin grille
no way to contact the prev owner
Once I get the old ones off I will let you know

Would there be a noticeable difference? theoretically with 2 identical cars

or just a difference in time on the track?

PS what is the stock ratio on rocker arms (what should I get) going to a roller rocker arm 1.5?, 1.6? brand?
 
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Old 12-10-2006, 01:16 PM
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Default RE: HELP!! 70cc or 64cc combustion chambers????

I think you would be looking at around 10 hp or less difference. The chamber size will change the compression .6 to .9 points depending on specifics which could put you above 10.5:1 running 92 93 gas.

Just curious but what heads are on it now? How much can you get a set of eldelbocks for?

The stock ratio rockers are 1.5:1(actually it is usally less) using 1.6 will increase you lift (take your lift divide by 1.5 mutiply this by 1.6=new lift) some guys will run both 1.6 intake and 1.5 exhaust. comp pro magnums are very good, I have not heard anything bad about Harlen Sharp. Reading you cam specs though I dont think edelbrock reccomends anything over 1.5:1.

Should be around 350 hp though.
 
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Old 12-10-2006, 06:07 PM
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Default RE: HELP!! 70cc or 64cc combustion chambers????

I guess just stock heads (do you want them?)
I just bought these edelbrocks $1,025 delivered (Ebay rulz!!)
[sm=americanasmiley.gif]
http://cgi.ebay.com/ebaymotors/ws/eB...2258742&rd=1,1

Do you know what length chromoly pushrods I should get, stock? 7.794"

These are the rockers I am considering...Which do you recommend?

http://cgi.ebay.com/ebaymotors/ws/eB...MEWA:IT&ih=016

http://cgi.ebay.com/ebaymotors/CRANE...QQcmdZViewItem
 
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Old 12-10-2006, 11:38 PM
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Default RE: HELP!! 70cc or 64cc combustion chambers????

EBAY is good but I keep getting outbid in the last 5 sec [:@]. You should measure the pushrod length prior to buying it is a bit more tricky with a hydraulic cam because of the lifter collaspe you need to use checking springs or a solid lifter but you want to make sure the geometry is correct. Do you know what size springs and stud sizes are on the head? As far as the rockers go between the choices you gave I would go with the crane my machinest said to stay away from the pro named stuff(I had a bad experience with the pro comp billit timing chain set) Ill PM you about the heads I am looking for a set for a project.
 


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