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throw me under the bus agian
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Discussion Starter · #1 ·
hey all, wonderin if i could pick up a little advise........im going to be running some aluminum heads on my 454, ( still shopping for exact ones) but right at the momment im buying pistons, my question is, dont i buy pistons with the correct shaped dome? i mean, its just like ive seen hella designs,( some 2 valve relief, some what looked like 1 valve relif, valve reliefs on what looked like opisite side, ect. ) i understand they affect comp. ratio, but should i buy the heads, THEN buy the pistons? i got 75 chev. stepside that i plan on running in the higher RPMS( direction of my build ) ( just a street truck, not a full out racer) also, at this time , is it a good time to figure out if im doing roller, or non roller?
 

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While buying the heads and pistons together would be the hot ticket, you don't need the heads first if you make a decision to the type and chamber size head you will buy and then spec the pistons accordingly to reach the compression ratio you are after.
 

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throw me under the bus agian
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Discussion Starter · #3 ·
heads

right on, im getting it, thanks , so im thinking, this thing will be a hog on gas anyway, so im still shooting for ?? mid grade? dare i say 89 octane? something like that, what comp. ratio would a guy be shooting for? also, do the benifits from a high comp. engine outway pump costs? what really are the advantages? ( im buying hyper pistons ) being able to open the valves more? ( also, the cam i choose, i want something super choppy sounding at idle, is that poss. with lower comp. ratio?)
 

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I wouldn't go pushing the compression ratio with Hyper pistons, 9.25-1 on midgrade. A "super choppy idle" and pump gas means a dog of an engine, you can't have both.

I'm not a fan of hyper pistons at all, Keith Black hypers exploding if pushed hard cured me of that, especially with pump gas. Hyper pistons are a poor place to try to save money IMO.
 

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throw me under the bus agian
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Discussion Starter · #5 ·
pistons

well, now, ive been juggleing with this one too,.... ive heard alot about forged pistons slapping around when cold, is that really true? i mean at one point i was set to buy some forged pistons, then i heard hyper pistons were not so bad, like with the stuff they put in them or whatever.....i mean just what kind of rpm can they take?
 

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Back in the day, forged pistons had to be fit loose and had piston slap for a bit when cold. Modern forged pistons are made of better materials and don't require huge clearances anymore and piston slap is no real issue.

Hyper pistons will handle nearly the same rpm as forged. What they won't handle is even a split second of detonation or spark knock without damage occuring. Not something you want to have when pushing limits of pump gas.
 

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throw me under the bus agian
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Discussion Starter · #7 ·
gas

so really, at the very least, i should be accepting the fact im going to be needing the high grade stuff, in order to come close to acheiveing what im after ( high rpms, the idle thing.....) so with that said, with forged pistons, on high (er ) octane, what would be a safe comp. ratio?
 

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I am using TRW/SpeedPro forged pistons,# 2465 here;
http://www.jegs.com/i/Sealed-Power/844/L2465F60/10002/-1
I have never heard any "piston slap" from them.I also have a set of Brodix Race Rite rectangular port heads,here;
http://www.brodix.com/heads/raceritebb.html
Mine have the CNC combustion chamber polish option and upgraded valve springs.With a deck height of 0.005 and the recommended gaskets this gives me a quench height of 0.044 and a static compression of 10.0:1.The best pump gas around here is only 91 octane,and sometimes I have put mid grade in and have never experienced any detonation or spark knock.Total timing is 36 degrees btdc,seems to work real good like this.My old cast iron rect port heads needed to have 38 degrees to work good,but that caused detonation.
Guy
 
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