I read that it can be hard to push an l98 to 400hp with the stock cast pistons, so I was wondering what would be a better choice, some hypertuerics, or some forged?

 

forged or course. What kind of power adder are you looking to go with?

 

Very soon Im going to be finishing a tbi to tpi swap, just need the injectors and tuning now, but I was thinking of a procharger. How much trouble is it to change pistons?
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Id like somthing strong enough to hold up well with 7 or 8lbs, and I dont want to buy injectors or bother with tuning until I know how much fuel its going to need and what kind of chip is required.

 

Forged would be best.

I would go with Diamond for your piston brand. I have them and love em.

 

Speed pro makes nice cheap forged pistons, might be worth looking at.

You need to remove the engine from the car and have it on a stand and completely disassemble it to change pistons. Are you getting in over your head here?

 

Yea, I dont have the working area or tools to remove the engine
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How do the stock pistons hold up to 5 or 6 lbs? Is it true stock cast pistons dont hold up past 400hp?

 

Yea, then you're over your head.

No that's not true. It's not that cast pistons are weak, and explode or anything, it's that they shatter from detonation easier than forged pistons. Don't let it detonate, then they're fine.

 

Does n2o have the same effect?

 

Yes, N2O is hard on pistons, but a 150HP shot is barely worth writing home about. People put that on stock pistons often. 200HP + is where you want better pistons, bigger ring gaps, stronger rods, etc.

 

So do you think I could achieve 400hp with a mild build and a 75 shot? When I say mild build I just mean with my current mods, subtract tbi, add a ported tpi.

 

No idea what your current mods are.
Port up the heads and put in a cam. Don't use a stock TPI intake, use a superram or something. Then yes, 400HP as is. You won't need the 75hp shot for that.

 

If you go N2O make it wet.... you'll be really upset with a dry 150 shot. Just throwing that out there.

 

L98 shortblock, .040 bore, 160 thermo, underdrive pully, a/c and emissions delete, true dual 2.5'' no cats, 2 arochambers, hooker shorties, xe262 cam, walbro 255 inline, and tbi induction for now. The tpi will consist of a ported tb, a coolant bypass, ported plenum, ported base, and an afpr.

 

You'll probably be pushing 300-320HP at the crank with that. Port the heads, upgrade to aftermarket intake and maybe cam it up a bit. Use a roller cam in a roller block man, like what the heck eh?
You've got another 40HP locked in the head porting and intake upgrade there. A lot cheaper than filling a N2O bottle a few times.

 

carefull when porting the L98 head, they are very very thin. look at mahle for forged pistons, they are decent price and are forged. they come with moly rings already installed. just make sure you tell whoever machines the block that you are running moly rings, they need a different crosshatch finish for seating.

 

The cam is a roller, and Im pretty l98 blocks are hydraulic roller, and I didnt mention but the heads are 093s. Im considering going with a edlebrock tpi intake kit, but I dont know about the edlebrock runners, does anyone recomend them?