I'm gonna buy a Ls3 418 or 427, I'm running L92's and a direct port L76 with standalone, which is better for nitrous? At the most a 250 shot.

 

I'd go with the 427 for the extra cubes.
Some will say the longer stroke will cause problems but who knows.

 

Would be tough to build a good nitrous piston for the 427.

 

What would you build? I can see you know what your doing!!!! I have p&p L92's and a port matched direct port L76 intake, 90mm tb, stand alone, 1 7/8 kooks, x pipe true duals, th350, pst driveshaft, moser 12 bolt 33 spline, eaton posi. full suspension, tubular k member and a arms.

 

https://ls1tech.com/forums/lsx-parts...hortblock.html

 

What heads work on that motor?

 

Just about all of them, the reliefs are pretty big.
I have had ET 225's , AFR 225's and now Cary's C5x heads on the same exact set up and they all worked fine with cam's up to 900 lift.

I dont see an issue with L92's on it.

 

i would do the 418 because its a proven stroke length, but some have got it done safely with a 4.1 inch stroke.

 

A stock piston would probably be ok if he's just gonna spray 250 BUT we both know how it goes. You start out saying just 250, then 300, then 350, then you end up using half a bottle per run. (1/8th mile) LOL

If you are TRULY only going to spray 250 any decent aftermarket piston will be fine as long as you know what you are doing. I've sprayed more than that on stock pistons without any issues.

Personally I'd go with the 427 because it sounds cooler when you say "I've got a 427 in my car" than it does when you say it has a 418.

There is no substitute for cubic inches. (Says the guy with a stock cube motor LOL)

 

I can't for sure say only a 250, I have direct port jetting for 400 shot

 

I doubt a 427 will hold up with 250 much less 400.

 

Like ATV said for a good nitrous piston stay away from the 4.1 stroke on a stock deck hight. as you increas stroke your piston "meat" gets smaller or your rod gets smaller both of which are not good on a nitrous motorn. we built a 396 for a reason over a 408 and its because you can hit the 396 much harder. You can have a 427 and be limited to 200 or a 396 and pump 400 threw it like its nothing. which do you think makes more and goes faster?

For the OP id get a steal on that iron 396 ATv posted then with the money you save ditch the Stock L92's and put a good set of ET's on it. It will make more on the motor and still take more punishment.

 

For the OP id get a steal on that iron 396 ATv posted then with the money you save ditch the Stock L92's and put a good set of ET's on it. It will make more on the motor and still take more punishment.[/QUOTE]

Thats what I'm trying to do now. ET what? 245's???

 

I like the ET ls7's, 245 would work if you want to stay cathedral.

 

When I was asking Erik about this he said the most he would spray on a 427 LS3 was a 200 and only if the tune was spot on.

 

Right and who's N20 tune is spot on right off the bat? NOONE!

Erik helped me pick my 396 parts and he designed the pistons.
He is a smart dude and my motor has taken a TON of abuse.

 

exactly. like ATV said Erik explained ot us why we should go with less stroke and a better piston and it has worked great.ThAT WAS 3 YEARS AGO. nOW WE HAVE A BETTER HANDLE ON THE NITROUS WE understand why.

 

My motor has taken more abuse than necessary and it takes it all and asks for more

 

me personally im buildin a 355 iron block for my camaro when all said and done im hoping to be runnin 750 to the wheels and to hold a 2 stage nitrous kit with 200 first stage and 250 the sec. stage

 

Are you saying you want 750 on the gas, because most kits are rated at the wheels. With a 200 1st stage and 250 2nd stage you would need a total of 300rwhp from your engine to reach your 750 goal.

Also with a shot like that I hope its purely a race car because the tune needs to be spot on depending on weather and DA, not to mention track conditions and race fuel only.

I may be wrong but I dont think the heavy hitters of nitrous are spraying that much, but I may be wrong.