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Discussion Starter #1
Looking to hear from you guys that are running carbed ls motors. I have a stock lq9 fed by a 770 holley thru an edelbrock performer dual plane. I'm using the msd 6010.

It's a heavy ass truck, 90's chevy. 6.0, th400, np208, Dana 60, Corp 14, 4:56 gears and 37"s.

What are your guys experience with the gm hot cam. I'm looking to get closer to 475hp as I assume I'm right around the 400 mark right now. I only have luck finding cam swap feedback from the street car guys but I think my application is a little different. Sand dunes, trail riding, mud bogs, and occasional street duty.
 

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While sand dunes and mud bogs require high revs, street duty and trail riding typically has the engine loping around just barely off idle. What you need to figure out is where you want the compromise to be. Try picking the cam based on the rev range you're after.

It would also be a good idea to consider your internal parts...rod bolts & rods, valvetrain..ect. The more aggressive your cam is the more expensive these upgraded parts will cost you.

If it were me, in a heavy ass truck like you describe with 37's and having an all-around off road truck...I'd look at cams similar to the Comp Cams XR269. Something in the 21x/22x range with a 1500-6200ish rev range. Just upgrade your valve springs and push rods.


COMP Cams: XFI™ RPM, XR269HR <BR> Great Mid-Range w/ Superior Top End Power, Needs Computer Modifications
 

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I swapped a cam in my silverado dd and it was pretty involved... I used a vinci high performance butt kicker cam
DUR @ .004" 272*/280*
DUR @ .050" 210*/218*
LIFT .551 / .551
LSA 114*

That was a great option for me because I wanted torque, yet still has great power winding on up to 6k... I also machined the heads to boost compression and did some mild porting on the heads.

Really think about this mod, because it would be in your best interest (and your wallet's) to beef everything up while your in there, ie: valve springs, lifters, pushrods, quality headgaskets, and new head bolts (must use new ones as they are torque to yield) I also upgraded to billet double roller timing chain and new oil pump to round it all out...

It gets pricey quick, but don't cut corners unless you want to do it twice! Don't ask me how I know...:shaking:
 

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Discussion Starter #4
to gearsturnin, what was your final compression ratio? with my lq9 I should be at 10.5:1 if I'm not mistaken. I have the 317 heads.

oldman, you mentioned the rods and rod bolts. I thought the bottom ends on these were good for over 500hp? The rpm range you mentioned is what I am considering, I don't see myself revving over 6000rpm. thanks for your replies.
 

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Old man is right. Figure out what rpm range you want to make power in and go from there. Cam/engine size and converter size all depends on the rpm range you desire.

Valve springs and pushrods are pretty much a necessity when doing any cam swap on these engines. Oil pump, timing chain, lifters and head gaskets are up to your own discretion depending on mileage.

DO NOT replace the factory rod bolts with aftermarket bolts unless you are tearing the entire engine down and having the rods rechecked with the new bolts. There have been more problems with spun bearings when doing this than keeping everything original.

The ls bottom ends are plenty strong factory and if you have an 05+ 5.3/6.0 I think they use LS2 rods and bolts which make them even more robust.
 

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My compression ratio worked out to be around 10.5to1 as well... I'm running a gen4 5.3 with 243 heads, I machined .035" off them bringing cumbustion chamber size to around 60cc. With the flat top pistons in factory gen4 5.3l thy puts my compression pretty high... Runs like a bat out of hell. Spins my 295/70/17s at around 68mph if I stab it to the floor...

I'm still on factory fi, so tuning may be considerably different for you I'm guessing...
 
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