Mild 5.7 vortec upgrades

[mkcustoms881]

Now I have done lots of reading but I really can’t understand or wrap my head around motor performance, I have a 1997 gmc truck with the 5.7 vortec? So what I have on my list is set of long tubes, and am gonna run either duals or 3 inch out straight, next I’m gonna upgrade spark system , now the hard part for me is cams I want an upgrade cam but don’t want to upgrade the springs and stuff like that and would like to upgrade the intake manifold if it’s worth it , what do you guys recommend? And am I on the right path?

 

[Supercharged111]

Don't waste your time on spark, just do exhaust and a tune. Tune will do more than exhaust, but exhaust is well worth doing front to back.

 

[Schurkey]

Any cam that DOESN'T need upgraded springs, retainers, guidework, etc. is probably not enough of a cam to make a difference. Not a major difference, anyway.

Yeah, expect a lot of computer "tuning".

 

[L31MaxExpress]

Davis Unified on the ignition. Was well worth the upgrade to me. I also went with an aluminum body distributor from RockAuto.

Headers & Decent exhaust will be much more noticeable than a tune on the 100% stock truck.

Proper tune after the exhaust upgrade will be very noticeable as well.

I would use the Comp 787 retainers and LS6 blue springs. They drop right onto the stock heads and open up alot of cam options. I would yank the heads to install them. Drill the pushrod holes out to 1/2". Then put the heads back on with a 0.016" compressed head gasket to get the quench as close to 0.040" as possible and give you as much compression as possible. I had a stock set of heads cut for 2.02/1.60s and milled 0.020". With the thin head gasket, the head mill and a little chamber cleanup I was at 9.6:1. Wemt with the GM 395' Marine cam and 1.6 rockers. Was night and day difference compared to stock and required very little additional tuning.

You can port the factory lower intake or convert to the L31 marine intake.

Volant makes a very nice cold air intake system that makes a noticeable power difference over the stock intake system.

 

[Supercharged111]

Davis Unified on the ignition. Was well worth the upgrade to me. I also went with an aluminum body distributor from RockAuto.

Headers & Decent exhaust will be much more noticeable than a tune on the 100% stock truck.

I always felt that the tune did more than the exhaust on my truck. Marine cam and 1.6s helped a bit as well.

 

[L31MaxExpress]

I always felt that the tune did more than the exhaust on my truck. Marine cam and 1.6s helped a bit as well.

Always the possibility mine responded better to the exhaust because it already had a tune setup for 91+ octane fuel. Post exhaust and headers I only cleaned up the MAF and VE tables. With the headers and full exhaust mine was pig rich.

 

[Supercharged111]

Mine was 91 octane as well, but I was in South Dakota at 3000ft elevation so that may have played a part. A year later when I went to CA the truck *****, then I discovered a some BTM BS that I'd missed and the right rear didn't want to hook anymore.

 

[Erik the Awful]

3" is overkill until you put in a big block; save a few bucks with 2.5" I went with long tubes and 2.5" all the way out with an X pipe between the cats and muffler.

From the HEI on, GM did ignitions right. I don't think there's much power to be gained there, but you do want a quality ignition module and coil.

If you go with a cam swap, this:

Any cam that DOESN'T need upgraded springs, retainers, guidework, etc. is probably not enough of a cam to make a difference.

You will need a tune afterwards.

 

[L31MaxExpress]

3" is overkill until you put in a big block; save a few bucks with 2.5" I went with long tubes and 2.5" all the way out with an X pipe between the cats and muffler.

From the HEI on, GM did ignitions right. I don't think there's much power to be gained there, but you do want a quality ignition module and coil.

If you go with a cam swap, this:

You will need a tune afterwards.

My 350 was factory dual 3" to the muffler. Not saying I would purposely build it that way but it worked well on my 350 and works great on my ~525 hp 383.

My 3.5 V6 has dual 2.5 with a X-pipe. Gained power everywhere over the stock Y-pipe that went down to 2.25 and then split back to 1 7/8" dual pipes.

 

[Realslimshady]

3" is overkill until you put in a big block; save a few bucks with 2.5" I went with long tubes and 2.5" all the way out with an X pipe between the cats and muffler .

I agree I used 2.5. Cheaper and sounds way better imo