97 305 vortec needs a little more power

I have a low mileage 97 305 Vortec. It is a low mileage original engine and I intend to keep it in the truck however, it could use a little more power. I have read the argument about swapping to a 350 or an LS a million times and that is not what I am trying to do, I don’t necessarily want a quarter mile truck, just a little more power. From stock it is supposed to make 230/280 and I would be very happy to see it get between 280-300 hp. Is this possible with bolt ons? Headers/intake/EFI plus maybe a cam? Or would it require some bottom end work? If you have any suggestions outside of an engine swap I would love to hear it. Thank you.

With a cam and bolt ons, yes. But I doubt you’ll get a 25-30% hp increase with bolt ons unless we’re talking a shot of NOS.

I have a new L31-R, hedman Black Maxx ceramic longtube truck headers, weiand street warrior intake, Holley Sniper, Dual Sync dist., MSD 6efi CDI, blaster SS coil and 8.5mm Super Conductor wires, 2-1/2” exhaust, h-pipe and Borla ProXS mufflers...in other words, every bolt on you can think of and I still can’t wait to get a cam when the engine warranty expires. That and a valve train that likes higher lift and more rpm.

Without a proper cam, you’re leaving a lot on the table with the bolt on stuff.

Before I did anything I would have Blackbear send me a tuned computer. Try that and see if you need more. Sometimes we get stuck on a certain hp #, when in reality, having something that is more fun to drive is a bigger deal.

A stock LS (smaller than 6.0) is pathetic down low. Like downshifts if the wind changes direction pathetic.

If I were in your situation with that kind of goal I'd agree that a tune would be a great place to start. I'd also recommend Black Bear Performance, they've been great to work with in my experience and will alter the tune at a later date free of charge if you want to change something. Personally I'd do something about the factory exhaust first though. The factory intake is fine for your application, but if you really want one get a Volant. They're the only ones who use a sealed box design that draws cool air from the factory fender hole.

I would also look into the 0411 PCM swap. The 96-97 blackbox cannot be tuned very well, and the 98-99 isn't much better. You will need to tune the PCM if you do a cam swap anyway. Well, maybe you won't "HAVE" to, but why swap parts and then not use their full potential?

I agree with df2x4 regarding the air intake, most of them are worthless and just a waste of money. Exhaust would be a much better option.

For the actual tuning I have heard nothing but good things about Black Bear, although I have not used them myself.

It is true that the 0411 PCMs have much more flexibility for tuning, but I wouldn't go so far as to say that the stock black box PCMs in these trucks can't be tuned well. Especially in a relatively stock application like this. They have their limitations but I see no reason to do the 0411 swap just for bolt-ons and a possible cam swap in the future. If you were adding forced induction or trying to learn to tune yourself then absolutely, but Black Bear can tune the stock PCMs just fine.

If you're willing to spend an hour and unpin and repin every wire to your pcm, I would recommend the 0411 pcm swap and a Blackbear tune. You can also get a gmt800 or gmt900 shifter and add a wire for tow/haul mode.
Like df2x4 said, I would do something about the factory exhaust if you haven't already. The 305 has a y pipe that brings bank 1 and 2 together. I would recommend either getting a 350 vortec exhaust which stays dual until it leaves the muffler, or going aftermarket/custom with 2-1/2" all the way through with dual mufflers and a x pipe. Headers are great too, but if you're on a budget, the 2500/3500 exhaust manifolds have larger primaries than the 1500 manifolds to allow more exhaust flow. I can't remember the exact size difference but there's a thread about it I remember seeing years ago here.

letitsnow said:

Before I did anything I would have Blackbear send me a tuned computer. Try that and see if you need more. Sometimes we get stuck on a certain hp #, when in reality, having something that is more fun to drive is a bigger deal.

A stock LS (smaller than 6.0) is pathetic down low. Like downshifts if the wind changes direction pathetic.

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6.0L is just as pathetic down low as all the other LS engines. The newer ones with rectangle port heads are even worse despite having variable cam timing as well. My uncle has a direct injected 6.2 and to me even it feels lacking on the bottom end to me.

I went low budget when I built the L30 I had in my 99 Tahoe. It was a 300K mile long block that I re-ringed and regasketed. New rings, bearings, gaskets, oil pump, etc. Found that the roller lifters where starting to lockup and had eaten into the cam. I swapped a Lunati High Efficiency 268 flat tappet cam into it with 1.6 rockers. On the degree wheel cam speced.
268/268@ 0.006
221/221 @ 0.050
.487/.487 lift
110 LSA, 106 ICL
I ran this cam with the old style Rhoads lifters. Perfect driveability and great off-idle torque with the Rhoads lifters was noticeably down on off-idle torque with standard lifters. I used the stock springs initially, but ended up swapping to LS6 springs and Comp 787 retainers. Valve job on the heads and milled them 0.020" installing them with a 0.018" compressed head gasket to get the compression up. Changed the lifters at the same time. Ran noticeably stronger.

I ran 1 5/8" primary long tubes with 2.5" collectors. Dual 2.5" pipes into thunderbolt 2.5" high flow cats, a magnaflow dual in/single out muffler. Stock truck intake that was ported, GM MFI upgrade spider, Volant cold air intake and tuned 0411 PCM. I had the newer body style tahoe electric fans on it. It made just shy of 270 hp at the wheels. The 4L60E had Superior billet servos, a Transgo HD2 shift kit and a 4.3 converter.