Would it be worth the time/effort to port/polish the existing heads, or just buy and install better aftermarket ones?

 

Time/effort means what to you?
What are YOU trying to accomplish?
What are your goals?
Are you racing a specific class?
How long are you willing to have the car down/tore apart?
How much money do you have/ are you willing to spend?
What are you going to do with the car?
Does anyone make an aftermarket GenV (LT1/2) head?
Are you planning future mods?- Cam/blower/nitrous/turbos?

Dude you asked a question NOBODY can answer but you. If someone does answer they are showing their ignorance and really don’t have a clue.
YMMV

 

Jesus man, feeling a little angry today ? I'm gonna show my ignorance and answer the question if that's ok with you.

​​​​​​I went down this road and talked to some people. They felt going with an aftermarket head like CID, Frankenstein or PRC LTX was a little overkill for a stock cam. I went into it twice and removed the heads, in the car. You'll need a zip wheel to cut the 1 bolt attaching the dry sump tank to the head on the drivers side. The passenger side comes right out.
The first time I just had the ports cnc'd. Because of time constraints I did nothing else. Car went 10.52@131. NA fbo.
The second time I took them out I had them shaved .040 on the deck and .020 on the IM side so those bolts lined up. I also ordered shorter pushrods. No valve work was done and with a .040 Cometic gasket compression is around 12.5-12.7:1 and it ran fine on 93 octane. My best e.t. then was 10.20@134. NA fbo before tuning became available.
This was my experience and mine only. You may want to check piston to valve clearance on your application if you go that route. I've read it is possible to go .060 and .028 Cometic with some bowl work and fly cutting but I'm not that brave. Drove 10k miles and multiple track days with that fbo/heads setup and she drove like stock.
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You were drag racing your car. OP never said he was drag racing or doing any type of tracking.

What was your combo to get to the 10.52? What other mods were done with the porting to take the car from 10.52 to 10.2?

 

Ok, fair response. Porting/polishing heads would yeild an increase in HP. How much would be gained is unclear. It'll be winter soon, and I have the ability to pull the heads myself, but think it wise to wait until car is out of warranty. I doubt that I'll go FI, because it's pricey and already have headers, intake, de-catted, and TB. I'd rather wait to see if/when transmission tuning and/or different gearing becomes available and perhaps end modifications with a cam/heads.

I don't drag race, but may do HPDEs and autox.

Not sure how much more I want to spend on performance mods, but understand tuning will maximize the benefits of what I've installed thus far.

 

Ported heads should net another 25ish HP with your supporting mods. Cost effectiveness? Probably not. Will it pick up sure.