reddfox

iTrader: (1)

I am building a 370 that will see some nitrous (300 max) and would like to know if I should run domed pistons with the 317 heads or flat tops with the 243 heads? Is it better to have the bigger cylinder head chamber and make up compression with the piston or make up the compression with milling the heads? Also how does quench and gasket thickness play apart in this decision?

A.R. Shale Targa

iTrader: (2)

flat tops/243 heads/GM mls head gaskets
NA engines love tight quench but I'd limit the spray to 150 in that case
If seriously spraying 300 just let the quench be in the .045-.050 range

speedtigger

iTrader: (16)

I have not done any personal testing on this, but I have read a bit about it in various places. Some credible people say that you want a softer chamber and to slow the flame travel down with nitrous to widen your safe tuning window as the amount of nitrous used gets serious (above 300). As I understand, the larger chamber heads with a dome piston is a slower burn scenario than a small chamber, flat top set up.

Many top nitrous guys also mention opening up the quench larger than what would be optimal for a naturally aspirated engine. I saw several nitrous combos (not specifically LS) that had .060-.070" quench.

lilaaron233333

iTrader: (10)

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onequiklx

im building a nitrous 347 right now. (plan on spraying 250-300). I went went TEA stg 2 cnc heads milled to 59cc. Wiseco flat tops. I set my quench up at 0.040 using a stock mls gasket(0.051). I was going to have the block milled anyways so i mocked it up with new rod/piston combo and i ended up taking the pistons out of the hole 0.011. I coulda ran cometic .040 and left the deck alone but i wanted it trued up. My compression should be close to 11.0 to 1. I talked to many big named ppl and they all said .040-.045 on quench. Tighter you go though the more sensitive it will be with timing.

reddfox

iTrader: (1)

I am willing to give up some N/A power for a safer nitrous tune. So if i understand correct you can adjust the quench with the head gasket thickness? This will be a carbed pump gas street motor with a stand alone for nitrous. Cam specs are 231/239 110 lsa

Rise of the Phoenix

iTrader: (27)

I agree with you. At the point you're going to be hitting it with a 300 shot on a regular basis, I'd make sure the engine is built around what's best suited for spray versus NA.

speedtigger

iTrader: (16)

You can. Cometic has a wide variety of thicknesses available.

reddfox

iTrader: (1)

Thanks for the info guys!