Is there ANY EX-HO truck(dont care what pump) over 550 hp?

C

ckassen

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Basically I am thinking of a SO pump on my truck. But after talking to people, is there even anybody who has even hit 550-600hp on a HO motor with a different pump? They say that the HO motor has higher compression which causes problems? I would think that it should help??
Thanks,
Chris
 
As far as I know, there isn't a compression difference. I've been led to believe that the only difference between the SO and HO motors was just the progamming in the chip on the pump.
 
There is a compression ratio difference. The SO is 16.3:1 and the HO is 17:1. Also, from the factory the HO injectors are the same flow as the 215 automatic trucks (98.5 - 00), not that it matters after your 200hp sticks.
 
Now the truth comes out. So now what. It looks like that only thing good in the HO's is the NV5600?

Is there any way to fix this without a new motor or 2k in parts? If that is a "no" then I guess I'm getting a CR.
 
yeah, a .020 marine gasket will help some, and you can flycut the pistons
 
Yeah I was thinking about the marine gasket. Does anybody know the actual difference in the motor that makes up for the compression? Rods, pistons, head?
 
Whats so bad about the high compression. Its great for street use imo. The only difference between a sovp motor and hovp motor is the injection pump and the pistons that have a tighter piston bowl as far as i know. Im guessing im over your 550hp but havent gotten on the dyno.
 
mayber he is thinking the rod's are slightly longer?:hehe:

sorry, had to!
 
Forrest Nearing said:
rods don't change compression... pistons do
Click to expand...

Although I doubt that the rods are what changed, shorter rods would decrease the c/r. Maybe you're thinking about my favorite when people say to use longer rods to make a stroker.:hehe:
 
Well the new trucks have 17.2 to 1 ratio and the 6.7's have 17.3 to 1 ratio, its not the compression ratio There is something different about the HO engines
 
My motor is an HO. Not running an ho or so pump but considerably over 550 with no problems caused by higher compression.
 
ckassen said:
Mind me asking what pump?
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He's run a few different p-pumps, and has made anywhere from 700-800+hp

I'm on an HO motor thats been thru a dozen combos of parts. Have a bunch of dyno runs of 560-570hp with a very streetable set-up. I ditched electronics for a p-pump and did 631hp un-tuned. Now I should be around 700-750 hp given the injectors, pump, and turbo I am running, but it doesnt dyno well due to the large turbo being laggy.

This is all done on a HO bottom end, with a .020 over head gasket
 
So would you say that the HO engine gave you a small disadvantage in HP? I did the math and cant seem to understand why the compression ratio would affect the HP. I dont think it does.

But someone on CF said that a guy with a monster pump on a HO only dyno'd 330?
 
ckassen said:
So would you say that the HO engine gave you a small disadvantage in HP? I did the math and cant seem to understand why the compression ratio would affect the HP. I dont think it does.
Click to expand...

I run a .010 over gasket(it's what they had available at the time). I don't think compression is an issue one way or another.

On CF that's all you are allowed to make. Thereare no HP restrictions on CompD.
 
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