Alright, i've been building engines for over a decade now, but have always been involved with old school chevy's and small block fords. I'm just starting to learn about the wonders of the LS1, so i'm looking for advice from the pro's here. A friend of mind has bought a 98 T/A and wants to build a nitrous motor for it. I'm going to list the parts we're considering and get some feedback from you guys.

Block:
LME Pro408. 6.0 Iron block, eagle 4340 crank, lunati pro mod rods, and -8cc dish pistons.

cam:
undecided. Looking for suggestions here

heads:
patriot LS6 cnc 2.08/1.65 valves

Intake:
Were considering the LSX, but want to keep the stock look as much as possible. Thinking LS6 here also.

We're researching the nitrous kit now as well. We'd heard that Nitro Dave has a hidden kit with the spray bars plumbed into the intake. Haven't had any luck finding it though. We're in the early stages now, just trying to select parts, and want to know if and where we're going wrong before it's too late. Thanks for all the help in advance guys.

Also, sorry for thin content here guys, but i'm in a serious rush (i'm in iraq right now and only get 20 minutes) Thanks again!

 

I'm no pro, but just curious.
What size/type headers would you put on this engine?
and are you looking to maximize power on the bottle, or more NA with a little bottle?

To me your parts list so far looks fine. I mean I can't see anything that's bad or in conflict, leaving of course the final decision on cam & head set-up.

Stay alert over there. I sure am glad I'm not in Iraq.

 

We're looking at 1-3/4 or 1-7/8. Like i say, still looking at parts right now. And we're really looking to maximize the power while on the bottle. We're wanting to shoot for 500 on the motor, then spray the ever-living crap out of it. He's even considered going with a blower or turbo setup, but is leaning toward the spray.

We're going to be doing it in stages, and will be ordering the shortblock in the next week or two, and will most likely be installing the cam at the same time as well...i'm going to search on here and see what has worked for others with the same setup and go from there.

 

Alright, after actually having time to do some searching i'm finding all the info i will ever need and more...i should be home in about five days, so i will be able to get a lot more work done then. Great site here guys...TONS of info. Look forward to spending a lot of time on here in the future

 

That's what I like to hear! I'm not an LS1 expert but I'm a hardcore bottle user. A power adder like nitrous especially likes closer intake/exhaust ratio because your intake valve becomes so much more efficient with the cold intake charge & higher oxygen. For that reason it's common to run a size bigger exhaust & primary tube to help power on the bottle. A big cube engine with bottle needs a healthy exhaust. The thing is when you go to a 1.875" or larger exhaust primary it starts becoming a mismatch to your 1.65" exhaust valve.
For a 1.65" valve, the seat (if it's 90% diameter) is only 1.485" wide. You have 1.485" feeding into a 1.875" pipe which gets further a way from a perfect match. It's generally better to keep the inside diameter of the exhaust seat fairly close to the inside diameter of your primary pipe. That suggests that if you run a large primary (good for nitrous) that you should go for a bigger exhaust seat and bigger valve. Some nitrous and/or turbo engines swap to the larger chevy big-block valve with larger stem and all. The larger stem supposedly transfers heat away from the valve better.

If you're building a big cube engine simply as a life-support system for a large nitrous hit, then you may want to consider setting the heads up with more exhaust bias. They'll work either way, but you may see a gain on the bottle.

I think the advantage of more exhaust bias in the head would be that you don't have to start blow-down so early in the power stroke. Larger valves generally flow much more at the lowest lift points than a smaller valve, so that allows a later exhaust opening event.

I don't know how much it would help; just throwing out that idea.
I do know that if you're getting your power from nitrous, you don't have to blow a lot of money on a larger intake tract.