98 up LS1 Camaro motor W/243 heads

[threewheelin007]

I bought a new set of LS2 heads stock my question is what would I have to change to stay as close to stock as possible with installing 243s on an LS1 block and how much HP and Torque would I gain.My other question is will this help or hurt my gas mileage.I know the last question is foolish to ask on this forum but I am a newbie and thick skined so fire away

[0rion]

I don't really follow what you're asking here so I'm gonna just give a broad answer and hopefully it'll help you. If not the ask a little more specific question.
243's will outflow your current stock heads but not by leaps and bounds until they're ported and polished. You will see a few more HP by just bolting up the 243's but if I were guessing I'd say less than 20. Gas mileage will probably be pretty close to the same.

[shady milkman]

^ with him...243s out of a ls2 will not have the lightweight valves or "yellow" springs that the ls6 243s had..so without those you will lose out on some power...but besides that..243s are a direct bolt on so there is basically nothing to mod ...the 243s where designed for the ls6 which was the performance version of the ls1. with the bolt dimensions being the same..the 243s will bolt right on...it is best that you put a ls6 intake or fast 92 on there for increased gains.

as the honorable Orion said..your gains will not be that great with a stock casting 243 compared to your stockers on now...you should send your heads into a reputable shop that does P&Ps gen III+ heads and really see them shine.