Lou Miller

I mentioned a couple different directions I was planning to go with a new truck. I'm back to going with an 8.1 2500HD (price was wayyyy too good to pass up).

What are the best mods for it? I'll have a custom tune and a CAI for it right away. Other than that, what are some of the things I can do to this big motha to get her moving? I'll probably end up with a Whipple unless I can find something else. I'd really prefer turbo (there's a ton of low end grunt stock, so that's not high on my list of things I want), but I'm not sure that would work well with 496 cubes.

I've read somwhere, thought it was here, that headers really make a big difference on the 8.1. Can anyone say if that's the case or not? The stock manifolds seem really small to me for such a big motor. Can anyone suggest a set of headers, it's 4wd though...

I've always been confused why the 8.1 is only rated at 330HP, yet the 6.0 comes with as much as 345 in some applications. Is the 8.1 really held back by GM? Or is it just more of a tourque monster?

I seldom see posts (although I'm fairly new to this site) about modding 8.1s, so any comments would really be appreciated.

Wilde Racing

iTrader: (26)

not sure about the 8.1, but I don't think it is a LS1 based block. More old school, but I don't know. congrats on the sweet deal.

LVSTOGOFST2002

iTrader: (3)

it's not an lsx motor, supposedly old school big block heads are the same, or similar. so it's basically just a newly engineered big block. Put longtubes on it, CAI, Cam, and a tune, i bet you'd see some extremely impressive numbers.

Also, the cam is very mild, but i dont 'know anyone who makes one. There's a few guys runnin around on here with 8.1.... be patient, they'll chime in. GM's tuning, is always for emissions, reliability, and milage..... so with a motor that big, imagine how detuned it is.

Mort

Congrats on the new truck and the sweet deal.

One of the problems with the 8.1 is that there are not as many around and they are a little different so there is not as ready a supply of mods as there is for the other gas engines.

Check with T Byrne Motorsports and you will find that Tom has a lot of experience modding trucks with the 8.1. He should be able to help you out.

Fogle07

iTrader: (5)

comp makes cams for the 8.1
http://www.powerandperformancenews.c...ry_Code=46-CAM

Lou Miller

Thanks everyone, I just picked her up today. 39,500 MSRP for only 24,500, not bad huh? It was a leftover 04 with 78 miles on it.

I drove it around today (about 100 miles) and it's pretty darn strong just the way it is. I guess 496 cubes has a way of feeling strong, eh? Anyway, I'll look into Tbyrne and some other stuff. I gotta let the newness wear off a little first. I can just imagine what this thing would run like with a Whipple on it though.

Wilde Racing

iTrader: (26)

that is a screaming deal, good job.

TieRod

It seams that I am the leading 8.1 guy. Mainly I haven't found to anyone that have out mod me on the 8.1's.
Stainless Works is the only long tube for it right now but The Other Guy headers makes a great mid length for it and you'll find that is the most popular one out their. STS offers a turbo kit for 8.1s I've head of guys ordering and seen pics of their kits but I haven't seen any results as of yet.
Both Comp and Crane offers cams but the Crane's are rather large and I'm not sure if the engine would have enough valve clearance. Comp's are much smaller and I gained 30whp and 50wtq with Comp's largest cam. Also the valve are heavy and the springs weak so a spring upgrade is a must with a cam swap.
With a cam, tune, and exhaust 8100hammer dropped 2 sec. off his truck.
BTW Their's more difference's between old school BB and 8.1 then are similarity's.

tbyrne

iTrader: (15)

Damn... that is an awesome deal! I've owned a couple of 8.1 trucks. One had an intercooled Whipple along with The Other Guys mid length headers, Volant induction, custom tuning and a few other bolt-ons. The truck weighed just under 7000lbs and ran 13.9 at the truck. Very fun to drive. The other is an '02 Silverado (extended cab, long bed). I'm running the same headers and induction along with a mild Comp Cam, roller rockers, custom exhaust and a few other bolt-ons. This truck also has is lifted about 8" and has 37" tall tires so 4.56 gears were needed. It goes pretty good with the current mods. They make the motor more efficent.

I suggest the same route with performance mods. If your looking for a big horsepower gain then the Whipple is a good choice. We've also sold a few of the STS 8.1 turbos. This will provide plenty of power when you want it.

The Wester's programming can be set up for power and fuel economy if you find that your stopping for fuel to often. Gives you the best of both worlds.

02_2500avalanche

I guess it all depends on how much money you want to spend. Rayler even makes aluminum heads and a high flow intake manifold but their stuff is pricey. I wish I had the money to buy their heads cause thats what my engine is missing. These engines are pretty well suffocated by gm from the factory, small exhaust ports combined with a small cam do nothing to instigate hp. If you boost this engine I would recommend you stay between 6-8 pounds of boost because the wrist pin area of the piston is weak and cannot take much more boost. You will also be suprized with what a nice set of roller rockers will do for this thing, they make it much more rev happy. Everything else has pretty much been covered. Modded 8.1's like Tierod said are few and far between but I wouldn't have it anyother way, its nice to have something different from the small block guys its even better when you drive by them and your truck is so loud it sounds like a four story building falling down

Alex