venomws7

Alright guys what would you choose for 408ci 4.030 Bore 9:5 Comp
YSI 16+lbs and nitrous future plans.

AFR225 Small bore slightly ported.
or
Stock LS9 Heads.


Thanks in advance guys.
Sam

Louis Gigliotti

Stock LS9 has a wing inside it that really hurts power. My vote is the 225s.

SquatchMachining

My vote is for neither.


Purchase a set of LSA Casting, hand port the "wing" out of the runner. (same wing the LS9 heads have) You can do this yourself or have a shop do it for a very minimal charge, it took me less than an hour to do it on both heads.


Get a Dual spring set from Brian Tooley, Fill the heads with Ferrrea valves. Hollow stem intake, Super alloy (Inconel) exhaust and you will have a killer head that will make tons of power.


I have the above mentioned heads on nearly the EXACT same combination you are listing. 408/YSI@20psi and I am making north of 1000whp at 6400rpm on 93 with Methanol injection.


The LSA/LS9 head castings use a better alloy and have a thicker deck than any of the previous heads, I cut a damaged one in half to verify this. They also have gusseted rocker bosses for increase strength.


The LSA head is a absolute no brainer mixed with ARP head studs and LS9 head gaskets. Not to mention, if you use the valves I listed, you will have light and very strong valve train, no worries of melting exhaust valves under that heat and cylinder pressure. You will have well under $2K into those heads all said and done.


Ferrea Competition Plus Hollow Stem Intake Valve - F2010P - $281.00
Ferrea Super Alloy (Inconel) Exhaust Valve - F1893P - $281.00
BTR Racing Platinum/Titanium Spring Kit - $299.00
LSA Heads - Shop Around - You will find them for as little as $650 per pair these days. You used to be able to get them for under $400 a set until GM realized they had a money maker on their hands!


That is $1,511.00 in parts and mind you those valves can be had cheaper as well. With machining and set up you are under $2000 all day long.

schpenxel

I'd love to know where you can get those heads for $650/pair. PM me if it's something you'd rather not post

Part number 12621773?

sr71bb

I know GM and others sell new ported LSA heads for about 890 for each head.

And I agree, the LSA heads will be you strongest option for a four bolt head. ARP head studs and LS9 gaskets as mentioned would complete the package. This PROBABLY would be good for up to 24-25PSI Boost. Past that and you need 6 bolt heads. Regular LS3 heads are probably marginal past 21 pounds of boost. My engine builder tells me LS9 gaskets seal a little better than Cometic.

SquatchMachining

I have pushed 28psi on the LSA heads with LS9 gaskets and ARP studs. Tune up and preparation of sealing surfaces are critical.


My local dealer sells the bare castings to joe public off the street for $360 a piece. So finding them cheaper is not an issue. When they first hit the market you could get them for $167 a piece, this was before GM realized that they had a very strong aftermarket and would make lots of money.

lt1z

LSA heads are a great choice on a 4 bolt setup. I run those as well.

venomws7

I forgot to mention that the customer have both already he will not buy any of them I'm sure there are a lot of better choices but between those two which one is Stronger or handle boost better.

THANKS For the comments guys I really appreciate it.

lt1z

AFR 225 would be my choice of the two but small bore kind of kills them a bit. The LS9 need porting.