4.8l truck motor-High revver?
12-13-2007, 08:46 PM
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4.8l truck motor-High revver? First of I know revver is not a real word. This question got me thinking and wanted to get some opinions.
So my question is the above statement relevant? Would a 4.8 be able to rev faster/higher than a 5.3/6.0? I can pick up a cheap 4.8 and was thinking a quick/high revving 4.8 with twins would be fun in a certain foreign car. So opinions/ideas.
Originally Posted by Pyrotechnic
I know everyone wants the 6.0 and the 5.3 but I was looking at the 4.8 a little since it's not so much in demand and may end up being a good deal. It's the same block and heads as the 5.3, but it has a 3.27 stroke crank and 6.278 long rods vs. the 6.098 rods that the 5.3/6.0 have.
3.27 stroke and 6.278 rods means a rod/stroke ratio of 1.92 which is VERY good. This is just a touch more than the 69 Z/28 302 (1.9 rod/stroke ratio). It should rev like crazy without too much stress on rotating assembly.
I'm just wondering with the stock rotating assembly, what kind of RPM's this motor could turn given the ideal cam and valve train.
3.27 stroke and 6.278 rods means a rod/stroke ratio of 1.92 which is VERY good. This is just a touch more than the 69 Z/28 302 (1.9 rod/stroke ratio). It should rev like crazy without too much stress on rotating assembly.
I'm just wondering with the stock rotating assembly, what kind of RPM's this motor could turn given the ideal cam and valve train.
12-13-2007, 08:54 PM
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i have a 2000 chevy with the 4.8 stong little motor and i wouldnt be afraid of a 5.3, but mines a five spd. as far as a faster rev im not sure but my truck doesnt hesitate any. it would be a pretty cool build and different.
12-14-2007, 12:07 PM
#5
The cranks in the 4.8L are weaker then the 3.622" that the 5.3L/6.0L and LS1 all share. In my opinion, it wouldn't be worth to build such a small engine, that is the same mentality of imports. You would spend the same amount to build that 4.8L as you would to build a 6.0L, yet the 6.0L would "rev" just as high and put down way more power per dollar. 
12-14-2007, 12:37 PM
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I'm going to build one for my AutoX BMW.
Sure it's a small motor, but at the ripe price free, what do I have to lose.
With the 4.8L and a 2100lb. BMW, you can't tell me it won't be fun. Heads/cam/tune would put it right at 380/320 @ fly and still cheaper than getting a LS or 6.0. Sure a LS or 6.0 would make more power, but I didn't get either of those for free.
Sure it's a small motor, but at the ripe price free, what do I have to lose.
With the 4.8L and a 2100lb. BMW, you can't tell me it won't be fun. Heads/cam/tune would put it right at 380/320 @ fly and still cheaper than getting a LS or 6.0. Sure a LS or 6.0 would make more power, but I didn't get either of those for free.
Last edited by StrikeZero; 12-14-2007 at 12:47 PM.
12-14-2007, 04:14 PM
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I'm going to build one for my AutoX BMW.
Sure it's a small motor, but at the ripe price free, what do I have to lose.
With the 4.8L and a 2100lb. BMW, you can't tell me it won't be fun. Heads/cam/tune would put it right at 380/320 @ fly and still cheaper than getting a LS or 6.0. Sure a LS or 6.0 would make more power, but I didn't get either of those for free.
Sure it's a small motor, but at the ripe price free, what do I have to lose.
With the 4.8L and a 2100lb. BMW, you can't tell me it won't be fun. Heads/cam/tune would put it right at 380/320 @ fly and still cheaper than getting a LS or 6.0. Sure a LS or 6.0 would make more power, but I didn't get either of those for free.
But yea I can get a 19k 4.8 for nearly half the cost of a similar condition 5.3/6.0 and there is a 300zx around the corner thats been sitting for a few years and needs motivation. My thinking isnt that of an import, but with the price difference and if it would be able to rev/faster higher(read quicker spool) than I would think it would be a fun drive.
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12-15-2007, 08:46 AM
#11
Hairdryer Setup w/4.8 crank/rods Here's where it gets neat! A 6.0L piston and a 4.8 piston have the same compression height. 
A 6.0L block with lq9 or LS2 pistons and a 4.8 crank/rod assembly would be a nice combo, almost the same configuration as an early 327 except with the much longer rod ratio. Tailor your head chamber size to the compression you want for your application (N/A or Boost
).
Due to it's low piston speed and increased piston dwell, this combo should respond well to turbocharging, especially with two small turbos sized for around 2.7L each.
A 6.0L block with lq9 or LS2 pistons and a 4.8 crank/rod assembly would be a nice combo, almost the same configuration as an early 327 except with the much longer rod ratio. Tailor your head chamber size to the compression you want for your application (N/A or Boost
).Due to it's low piston speed and increased piston dwell, this combo should respond well to turbocharging, especially with two small turbos sized for around 2.7L each.
12-15-2007, 10:31 AM
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Here's where it gets neat! A 6.0L piston and a 4.8 piston have the same compression height.
A 6.0L block with lq9 or LS2 pistons and a 4.8 crank/rod assembly would be a nice combo, almost the same configuration as an early 327 except with the much longer rod ratio. Tailor your head chamber size to the compression you want for your application (N/A or Boost).
Due to it's low piston speed and increased piston dwell, this combo should respond well to turbocharging, especially with two small turbos sized for around 2.7L each.
A 6.0L block with lq9 or LS2 pistons and a 4.8 crank/rod assembly would be a nice combo, almost the same configuration as an early 327 except with the much longer rod ratio. Tailor your head chamber size to the compression you want for your application (N/A or Boost
).Due to it's low piston speed and increased piston dwell, this combo should respond well to turbocharging, especially with two small turbos sized for around 2.7L each.
Im not sure what piston dwell is but ill look it up. Dont know much on the technical side but im open to learn plenty.
12-16-2007, 11:00 PM
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Also was just thinking if i did get the 4.8 and later I wanted more power from it I could just bore it out to 5.7. My goals are modest to start, mid 12s on a stock motor with boost so i believe i could get it done with the smaller 4.8
