5.7 power numbers

[Cool Zr2]

I might have asked this before but I don't remember...

 

Does the 4 bolt 5.7 vortec have different power numbers than the 2 bolt? Do they have different cams for the different applications? (3/4 ton vs. 1/2 ton)

 

I am assuming that the 4 bolt motor has less power becasue it is designed to run higher rpms in the 3/4 tons.

[Cool Zr2]

Anyone got any info on this?

[Wingnut]

My 5.7 puts out around 400 hp.

 

 

Then I wake up and realize that's just how many times I hit snooze.

[Cool Zr2]

My 5.7 puts out around 400 hp.

 

 

Then I wake up and realize that's just how many times I hit snooze.

 

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I was reading your post and a knome just took a leak on my big toe, d**n them, they always get me when I least expect it.

[carl722]

I think it was a little less power and more torque. The heads are also different they are 72cc instead of 64cc.

[snoman]

I think it was a little less power and more torque. The heads are also different they are 72cc instead of 64cc.

 

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Head chamber volume means little since piston can be dished to control compression ratio. GM used to used 4 bolt block in truck because the bottom end was a little stiffer in theory and a good marketing tool too. HP wise there is not design difference as all of the parts except for main bearing cap will interchange between 2 bolt and 4 bolt engines. If you plan to pull more than 400hp or so regularly or use a supercharger a 4 bolt is a better choice but in relatively stock use there are no problems with a 2 bolt block.

[wlrottge]

My 5.7 puts out around 400 hp.

 

 

You want to enlighten us as to what you did to get that 400 hp?

 

Has anyone put 1.6 roller rockers in theirs? How much head work was required?

[carl722]

I put all the spec of the cam the vortec heads and other information on the engine into my desktop dyno program and it shows somewhere around 320 hp @ 4500 rpm's and 430 ft/lbs @ 3500 rpm's. After the program I would say this is pretty close since I don't have problems pulling away from the 300 hp 6.0L trucks. I would like to dybo to see what the RWHP is but I don't want it bad enough to pay for the Dyno run. I know the basic rule of thumb is 19 to 20% parasitic lost for the drivetrain.

[snoman]

I put all the spec of the cam the vortec heads and other information on the engine into my desktop dyno program and it shows somewhere around 320 hp @ 4500 rpm's and 430 ft/lbs @ 3500 rpm's. After the program I would say this is pretty close since I don't have problems pulling away from the 300 hp 6.0L trucks. I would like to dybo to see what the RWHP is but I don't want it bad enough to pay for the Dyno run. I know the basic rule of thumb is 19 to 20% parasitic lost for the drivetrain.

 

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These desktop programs are highly subjective and greatly overrated and I would not give them much do as they error to the generous side not the real world side by design.