Putting together a 6.0L for daily driver duty. I want it to be capable of running hard every day. Truck is a 4400# half ton with stock converter, 4L80 tranny, and 3.73 rear. Forged short block and will have Livernois ported 243's. 10:1 compression ratio, 90mm t'body, LT headers and full 3" dual exhaust. Cam is a 223/227 .610/.614 113lsa.

What do you guys think would be a good way to go with the intake manifold? From what I've read, spending money on an aftermarket mani might not be a good use of funds. Any low buck options better than others? Are some stock manifolds better than others? Is porting any particular stock manifold a good investment? Help appreciated.

 

I run the NNBS intake that people seem to have godo luck with. I put it on at the same time as the new cam, so I can't speak to what I gained from it exactly. The biggest reason I went for it was because the 08 flex fuel trucks come with bigger injectors and I needed some for the cam.

People say as far as factory manifolds go this is the best one fos us because you get the top end gain of a 90mm intake and gain torque down low because of the longer runners.

 

Thanks, I have 60# injectors left over from the f/i set up. Might sell them if they are a problem with the n/a motor. NNBS intake? Please let me know. My truck has been Maggie blown since '05. I've done quite a bit of reading, but admit my ignorance. My experience with LS motors without a blower on top is pretty minimal.

 

I run the nnbs/trailblazer ss intake manifold, gaines I believe are 10-15 rwhp over stock through out the entire rpm range and beyond 6k rpm ....deffenatly worth the money over th fast intake manifold that goes for about $1k IMO ..the nnbs/tbss can be bought for give or take $100-$300 .. deppending on were you buy it from....

 

Just as these guys said, the TBSS/GMT900 intake is the best bet from the factory for sure. The Fast LSXrt has shown awesome gains on the dyno, probably the best of em all, but, as with everything associated with Comp, there have been quality issues and brand new, out of the box intakes that don't fit properly and/or leak if you are lucky enough to get it to bolt up

 

I am looking into intakes you can find them used for 200$ on the forums frequently. it's 900 for a fast. I am reading 15 vs 30hp. buy once money saved or over spending. I am stuck on it.

 

Ive personally installed between 10-15 of the FAST LSXRT manifolds and have never had any issues. I think its the only way to go, do it once and do it right. (read instructions)

We even tested it against the TBSS/NBSS intake. This truck was a 2007 5.3L truck that came factory with 243 heads and TBSS intake. That truck was 100% stock, absolutley zero modifications and we swapped the LSXRT, never tuned it or anything just simply dropped on the intake.

We made a few runs before the swap and a few after, the LSXRT made 21rwhp over the TBSS/NBSS intake on a stock 5.3L. I bet there would be another 10hp with tuning.

 

^no one is doubting the gains of a fast over any factory intake. The whole point is a tbss/nnbs intake a nice, low dollar alternative to a $1k manifold.

Op,

You're going to want to get a higher stall torque converter.

 

I would love to run the FAST intake as well, but hoenstly I did the swap for the bigger injectors. It only cost me $100 more than buying a set of used 8.1 marines... try to tell me thats not worth it.

I think between my cam and this intake I added north of 50 peak HP at once.

 

I've found the FAST intake for $850 shipped. Guess I have to decide if 15 or 20 extra hp is worth 600 bucks. I wonder if that 15 or 20 would be quite a bit more on top of a heads/cam LQ4. Hmmmm.. Any thing else to consider besides the cost? Is the FAST a true bolt on without a lot of drama and multi trips to the parts house trying to make things fit? I already have the 90mm t'body.

RE: higher stall tq converter? Do you think my cam is too big to be run with a stock converter? I thought it was about as big as I could go and still run the stock converter. I not a fan of higher stall speeds in a street/work truck. I'll back off on the cam before running a loose converter.