Changing the cam timing will not change the LSA.The LSA is ground into the cam & it is what it is.With that heavy body,the stock cam would probably be a better choice than the LT1.A better option for you tho is the Ramjet cam(#14097395).This cam will give you tons more of lower rpm torque(approx. 380 to 400 ft/lb) from 1800,or,so,up thru 4800 to 5000 rpm.Adding 1.6 rockers on the intake helps too with this cam in a stock Vortec.Even adding 1.6 rockers to the stock cam would,IMO,perform better than the LT1 cam for your vehicle & it's weight.
The Ramjet,if not familiar with it,has duration @ .050 of 196/206 & a 109 LSA & 109 ICL.However,it ground approx. 3* advanced,giving an ICL of approx. 106 installed straight up.Normally the 109 LSA would cause problems with the computer,but,the durations are so short,that it actually runs well.It could however,benefit a lot with some pcm tuning,as will even the stock cam,or,any cam swap for that matter.
Advancing the LT1 cam would help some, but, not enough to make a big difference as you will still be losing cylinder psi with it's later timing.Honestly, you'll need tuning to realize any substantial gain with any cam swap.That cam is designed to run with 10:1 & make power later in the rpm range.

 

Changing the cam timing will not change the LSA.The LSA is ground into the cam & it is what it is.With that heavy body,the stock cam would probably be a better choice than the LT1.A better option for you tho is the Ramjet cam(#14097395).This cam will give you tons more of lower rpm torque(approx. 380 to 400 ft/lb) from 1800,or,so,up thru 4800 to 5000 rpm.Adding 1.6 rockers on the intake helps too with this cam in a stock Vortec.Even adding 1.6 rockers to the stock cam would,IMO,perform better than the LT1 cam for your vehicle & it's weight.
The Ramjet,if not familiar with it,has duration @ .050 of 196/206 & a 109 LSA & 109 ICL.However,it ground approx. 3* advanced,giving an ICL of approx. 106 installed straight up.Normally the 109 LSA would cause problems with the computer,but,the durations are so short,that it actually runs well.It could however,benefit a lot with some pcm tuning,as will even the stock cam,or,any cam swap for that matter.

Yea I had originally looked into that cam slightly, but was thinking the 191 to 196 jump in duration wasn't going to have much effect. I don't know much about how these engines respond though.

 

As for milage, yes it will help.You get more ooommmph with less pedal.Wether it will run 87 will be dependent on the tuning.I have the cam in my motor.I do run 87 for daily driving & use 91 for playing around, or, heavy towing.If the pcm senses detonation, it will adjust timing to correct it.This will hurt power slightly tho.My truck is an extended cab Z71, short bed.IIRC, my curb weight is 4600.I would think yours is somewhat more.I would say at least 5500.By the way, I average aprox 17.5 mpg on the highway.Around 14 in town.Your stock convertor will work fine.

 

You realize my Tahoe is the 2 door right? I think its shorter than a regular cab short bed k1500. I can't see it weighing 5500. I was thinking 5000 max.

 

Yeah,you're rite.I forgot you said 2 door.I would say somewhere between 4600 to 5000. It probably is close to the same as mine.You could always run it across the scales at a truck stop for a few bucks if you wanted to know for sure.

 

Either of those cams will run ok on the stock tune,but,not optimally.I ran mine on the stock tune for awhile.I would get an SES light occasionally.The 96/up controllers have some self learning,but,very little & can adapt to minor changes.You can disconnect the battery for a minute or so,then hook it back up & drive the vehicle normally for 10 to 15 miles & it will make adjustments as long as yopu don't get way off of the stock parts.
A PCM tune can gain you as much as 20 HP,depending how aggressive the tune is.For these gains tho,it would require 91/92 octane & lowering t'stat temps.

 

I was planning on getting long tube headers, with a x or h pipe 2 1/2" all the way back into a dual chambered magnaflow muffler most likely. Also, removing the lip off the throttle blade, getting electric fans, and mobbing up my own intake to grab air from either the fender or make a ram air. Probably grab this HT383 cam and get it tuned by black bear. That will hold me off until I find a LQ4 (6.0L) since they have way more potential. All I need is 87 octane, don't necessarily care for MAX hp, torque is more important.

 

Only reason I'm upgrading the cam is, because I hear the stock cam is terrible and is leaving a lot on the table.

That bad reputation is from a hotrodder's standpoint... it's a very short durations cam, like ~184/~196 durations, shorter even than the base cam in car SBC 350's and 400's... but it's a good cam for your purposes... roller and higher lifts per duration for added torque... there might be a little gain by advancing your stock cam by 2 or 4 degrees... and getting a low RPMs/MPG computer tune... and/or a custom made short duration cam with wider LSA... LS7 427" Corvette engines used shortish 210 intake duration, wider 229 exhaust duration, and ultra-wide 121 degree LSA cam for 30 MPG, 7,000 RPMs, and ~530 open header HP... I think the HT383 cam is the same as the RamJet 350 HP engine cam... might be better off grabbing the HT 383 stroker crankshaft, rods, and pistons... but that would require backup parts like bigger injectors and ECU tune...

As Joker says, going to a cam with more duration for higher RPMs is going the wrong way for your goals... and the EFI LT1 350's were known for especially weak low RPMs torque, but sang at higher RPMs... also partly from short intake manifold runners... Basically, TPI runners too long... LT1 runners too short... LSx runners about the right length... You might like the low RPMs torque TPI setup designed for Vortec heads...

 

I don't think BlackBears still works with the 96/97 PCM.IIRC, he only does 98/up.You'll need to check with PCMFORLESS, or, Sinister Performance. There are others that can do good job as well for setup like yours which won't need a whole lot.
Your setup uses a single MAF sensor so you will need to be careful how plumb in any intake ducting.Using a dual ram air would be pointless as all air will need to pass thru the sensor so that will still be the flow limiter.The stock system is really not that bad to be honest & carry enough air to support theTB & stock intake with a good filter.

 

I think he's just thinking ram air to get cold air for more torque and better MPG and less chance of pinging...

 

When I hear Ramair, I think of dual snorkel unit s GM used.Most of the cold air intakes marketed for these motors are worse than the stock system, which already pulls it's intake air from outside the engine bay in stock form.Most of the aftermarket units draw from inside the engine bay.

 

So I'm pretty set on the ram jet cam. Just a few questions will my stock springs handle this cam okay? I was thinking about Z28 or beehive springs otherwise. I read I can remove the dampeners on the Z28 springs if I choose those, they are only $30. Is it safe to do that? I figure the engine probably needs new valve springs at 119k miles anyway, it would be smart to change them. Can I reuse my old lifters with the ram jet cam? And last thing will this cam really give me 400ft.lbs of torque from like 2500-4000rpm just like the ram jet 350? Just looking for something to help tow and get better mpg's. Thanks

 

The 350 Ram Jet and the HT383 both use the same valve springs as the stock Vortec 350. The part number is #10212811 for a single spring, and #19154761 for a set of 16 springs.

 

With 119K miles, and new ones only about $100, I'd put new roller lifters in... seen them go bad at 60K...

 

The stock springs will work, but, they weren't that great new.If I could, I would replace them.SDPC sells the z28 springs w/o dampers for Vortec heads, but, my preference is the LS springs with Comp 787 retainers.
You will be very close to 400 ft/lb.Condition of the motor, tune, etc will play a part in the final #.Inspect the lifters very good.Roll them up your arm to check for any noise, tight spots, rudeness.A new set of Delphi lifters is only $100.I've seen these lifters go in a well taken care of motor for 300,000 to 400,000 miles with no problems tho.It's a matter of how lucky do you feel ??? LOL.

 

I just looked up the stock vortec spring replacement and they are $88 at summit. It will be around $100 for the LS6 springs and Comp 787 retainers. The last engine I used LS3 springs and 787 retainers on vortec heads and the springs went on a little tight around the boss, I don't know if I should worry about that and use them again on this 350? Or just stick with the original replacement springs. I'm not going to modify this engine anymore past the ramjet cam and 1.5 rockers. If I ever want more power I'm dropping in the LQ4 6.0L.

 

Yep.Mine too.No lope at all.The duration is so short that the 109 LSA doesn't have a big effect on idle, or, even vacum for that matter.I have duals into a 3.5" si gel pipe, so, mine seems really smooth.Plenty of video on YouTube in various setups to get an idea of how it sounds.It will have a slight lope in 305.

 

I didn't really want to do 1.6 rockers, because I read I need to drill out
the pushrod holes bigger or something? Plus this would put valve lift over that
.460 margin for the vortec heads unless I got beehives.

cant remember what year they changed, but

IF ? you have self-aligning rockers??
you don't have to drill the pushrod guide holes in the head..

IF you drill them?
then you need to run ether pushrod guide plates or self-aligning rockers..

 

The vortec heads use self aligning rockers.If using 1.6 rockers, it is almost always required to open the pushrod holes up for added clearance. Doing so does not require you to use guide plates.The standard holes are 7/16".Opening them to 1/2" is sufficient.