So many choices, so little money. just need to cure that craving for rice,lol
11-14-2003, 08:08 PM
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So many choices, so little money. just need to cure that craving for rice,lol Well, pretty soon I will be undertaking the task of swaping an ls1/t56 into a 1st gen s10 for my dream sleeper. 
I know that it's definitely going to be an ls1, and I do want to do a few mods to start off with, but I am on a limited student budget right now. My first idea for more power and a few minor mods, is to swap a set of 4.8 heads along with some bigger springs, injectors, valves, and cam and exhaust. And I got to thinking, adn if I am not mistaken, the heads will raise the cr, but will they flow well enough to fulfill the needs of that engine with cam? And with that combo, i would figure somewhere around 350 at the wheels give or take a little.(correct me if you think other wise) Also, a stock ls1 cr is around 10:1, and with the smaller cc heads should be around 11:1, but if I were to order a set of je pistons that are hi comp 11:1 with stock heads, does anyone know approximately what the cr would be near, and again if it would be worth it with the 4.8 flow numbers or not. I would appreciate any information given. Although, I have to say, the sounds of that new eagle stroker crank is MIGHTY tempting. 
I know that it's definitely going to be an ls1, and I do want to do a few mods to start off with, but I am on a limited student budget right now. My first idea for more power and a few minor mods, is to swap a set of 4.8 heads along with some bigger springs, injectors, valves, and cam and exhaust. And I got to thinking, adn if I am not mistaken, the heads will raise the cr, but will they flow well enough to fulfill the needs of that engine with cam? And with that combo, i would figure somewhere around 350 at the wheels give or take a little.(correct me if you think other wise) Also, a stock ls1 cr is around 10:1, and with the smaller cc heads should be around 11:1, but if I were to order a set of je pistons that are hi comp 11:1 with stock heads, does anyone know approximately what the cr would be near, and again if it would be worth it with the 4.8 flow numbers or not. I would appreciate any information given. Although, I have to say, the sounds of that new eagle stroker crank is MIGHTY tempting. 
11-14-2003, 11:14 PM
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Well, to start with, damn thats a helluva project. Good luck.
Now, yes the heads will up the compression ratio. Stock 5.7L LS1 heads sport a 10.1:1CR. The 5.3/4.8's run around 11.1:1. Second, ported heads should flow enough to satisfy your needs, yes. The heads are just changing the compression ration as I understand it. All of these ideas of compression change when you change the stroke of the motor. So do your math for stock stroke, but then do a whole other set of calc's for a different stroke. The pistons will have an effect, just watch the P2V clearence if you mill your heads any and you throw in a decently aggressive cam.
Now, yes the heads will up the compression ratio. Stock 5.7L LS1 heads sport a 10.1:1CR. The 5.3/4.8's run around 11.1:1. Second, ported heads should flow enough to satisfy your needs, yes. The heads are just changing the compression ration as I understand it. All of these ideas of compression change when you change the stroke of the motor. So do your math for stock stroke, but then do a whole other set of calc's for a different stroke. The pistons will have an effect, just watch the P2V clearence if you mill your heads any and you throw in a decently aggressive cam.
11-15-2003, 05:58 PM
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Ok, so if the truck 4.8 and 5.3 have the same cr, then would 5.3 heads have the same size chambers and offer the same cr gain as the 4.8 heads? Or do they have different piston deck height or something? Because if so, then I might as well just go with a set of 5.3 heads, and wont have to do as much porting to get the flow numbers back to what the ls1 heads are(or better).
thanks for the info so far.
thanks for the info so far.
