RGV_Z28

iTrader: (7)

Right now my car is making 401 rwhp and the car is still untuned. I heard that a stock bottom end ls1 can only handle like 450 rwhp, is this true?? If that is the case, with a tune i should be at like 420. Is it worth to get heads or just save the 2,000 towards a 408.

bowtieman81

iTrader: (35)

If your question is are heads generally worth the cost then the answer is yes. If you are like me and want power all the time, versus nitrous which is on/off, then heads are a good option. And the stock bottom end can handle 450 rwhp, its more a question of use and tuning. Many guys on here are at that level or darn close with no problems.

Now, you mentioned 408 in the future. If that is what you plan to do I would NOT buy heads for your engine right now. The bore size of a 408 is much bigger, to big to work well with 3.9" bore heads. It seems AFR 225 heads are a good choice for a 408 based on some of the guys on this board. Search around a bit for more info. Hope that helps.

transam1998

iTrader: (5)

Bob at EPP has regularly stated that the stock pistons will handle up to 500 rwhp. You probably won't come close to that number just by adding heads.

And, yes, if you choose to go 408, you will be a bigger bore. and require different heads than your 346.

Brandon Boomhauer

iTrader: (10)

You could run HPE's Stg 3 5.3s, which would be great on a 408, with around a 8cc dish piston.

You can overkill the stock shortblock (although it wont be optimal, it will make more power) with heads for a 408. You could save the money for the 408, then run the 408 with stock heads, which isnt optimal for the large ci, but will make more power than a h/c 347.

mike c.

iTrader: (1)

i gained near 50 rwhp adding the AFR 205 heads to my camed 346ci. heads are worth it,but you get what you payfor. on my 402 i'm adding the AFR 225 heads.the AFR's perform and at this point i will not run anything but them. goodluck to ya.

Z06-Dave

Heads are definitely worth it.
To steal a quote from Mr. Mamo himself "Heads are where it's at!"

SLowETz

iTrader: (12)

Heads make power. Period. Everything else is just supporting parts.

smask04C5

iTrader: (1)

Best money spent was the AFR's

silverTA2002

iTrader: (1)

Yep, heads are worth it. I'm ordering some tomorrow.

BTW, how the heck are you making 401rwhp untuned??? What's your 1/4 mile?

WS6FirebirdTA00

iTrader: (33)

what cam do you have, if its not big dont look to gain 20 hp from a tune. if your tune was off before it may have it right on now. although i could be really wrong. lol anyway what size cam?

orangeapeel

iTrader: (18)

heads = yes....anytime you need more power it is always there.