Joeyofblades

iTrader: (2)

Hey everyone, I have a question that I've sent to Texas Speed but also want some people's opinions as well. Let's begin with the main question:

How do PRC 2.5 upgraded LS1(241/853) heads stack up against PRC 2.5 upgraded LS6(243/799) heads?

The flow chart for the end product can be seen at this link, however read the wording above the chart... it specifically says LS6 cylinder heads. Meaning this chart represents your end product if you send them 243/799 heads. I can't find a flow chart for the end product you get if you send them 241/853 heads for porting.
https://www.texas-speed.com/p-1172-p...-castings.aspx

Now, for some information about myself. I have an SLP lid, stock MAF, stock TB, and ls6 intake. This is a street car that is currently daily driven and will be for a while, and will be seeing occasional drag strip after I get my house and a daily driver this summer. The car has a built 4l60e with a 3800 loose stall and 3.73s in the 10-bolt. The car is a 1998 so I currently have 806 heads. I have a cam whose specs I will attach to this post. My heads are my limiting factor right now and I want to change them. I have received a set of 853 heads for free from a friend. I am wondering if I get these ported with the 2.5 upgrade and put them on if I will get the most efficient setup while keeping the ls6 intake (I do not want to go FAST 92 or 102 at this time). OR, if I should buy 799 heads from my other friend for $400, send those to get 2.5 upgraded, and put them on.

I am waiting for a reply from Texas Speed on the flow #s for the 2.5 upgraded 853s I'd have if I sent them the heads I currently have sitting in my room and their opinion on what the right choice is for me, but was wondering if anyone here had any personal experience with doing this and any footsteps I should follow in or mistakes I should learn from. I COULD spend the extra $400 for the 799 heads, but would prefer not to, especially if the end product will be overkill for the rest of my setup.

HCI2000SS

iTrader: (2)

The 243/799 heads will get you another 20 hp or so

Peetyz

iTrader: (7)

PM sent. I would strongly consider the 243 or 5.3 heads over the 241 casting.

R6cowboy

iTrader: (3)

The ported 799 heads will be a slight upgrade from the ported 853's. Is $400 worth it for the 799's, I think it's not a bad deal at all. If I were in your shoes, I'd do it if I could swing the extra $400. But don't think ported 799's is going to be a night & day difference from ported 853's. Honestly, you probably wouldn't even notice a difference on the "butt dyno".

Joeyofblades

iTrader: (2)

I'm expecting a considerable difference from my 806 heads no matter which one I choose but between ported 853 and 243 20hp might actually be worth it... do it once do it right I guess. Thanks for the input guys, everyone else feel free to chime in too as I'm still deciding.

Darth_V8r

iTrader: (4)

In general, I see the 243 as the best of the factory cathedral ports, and I just don't think you'll go wrong with them. And be honest with yourself - will you in a year ask yourself what if? If the answer is yes, then just get the 243 and know you left nothing on the table

99 Black Bird T/A

iTrader: (4)

15 to 20 hp for $400 is a bargain...in my book...I'd do the 243 castings for my new cylinder heads.

Joeyofblades

iTrader: (2)

Texas Speed Replied:
Wow, this makes this quite a bargain. Only 10-15cfm less? If he's right, the 862s are by far the cheapest and most efficient option.

CoonAssZ28

I just picked up some 243's and was considering the PRC 2.5 option as well.

Joeyofblades

iTrader: (2)

Definitely best bang for buck I can find. Especially since it seems like you can't find a lot of ls6 heads anymore. They've moved on to LS3 and even LT1 stuff now. I'm going to request actual flow chart and see if they could get my compression to 11:1 on those 862s if they port them. I'm liking this guy's responses so far and TSP has come through for me before!

HCI2000SS

iTrader: (2)

I run the PRC 862's and for the money I think they are a great bang for the buck

Joeyofblades

iTrader: (2)

Thanks brother. I'll be following in your footsteps soon. About to reply and ask him if they can mill me down and get me to 11:1 compression. More free HP

HCI2000SS

iTrader: (2)

Glad to help. They should be able to get you there no problem I'd imagine

R6cowboy

iTrader: (3)

I would recommend the 862/706 heads over the 853/241 also. Getting 11:1 SC shouldn't be a problem with the 5.3L heads. I'm not too sure if you will get an actual flow chart for the specific heads you get ported. When I bought stage 2.5 5.3L heads from TSP before, I requested this and all they would give me was a snapshot of the flow chart that was already listed on there website. They wouldn't produce a flowchart for the specific heads I received. But that was 4 years ago, things maybe different.

Peetyz

iTrader: (7)

I'm running the 5.3's milled at 59cc and have around 11:1 compression.

Flow chart for PRC Stage 2.5 5.3 and LS6.



https://ls1tech.com/forums/generatio...2-5-heads.html