I’m in the process of boosting my Vette. FBE 402 LS2 block, custom BTR blower cam, YSI blower etc. My current 243 heads had a BES CNC port, valve job, milled .020, BTR 660 dual springs, TI retainers, stock rockers with trunion upgrade, and stock valves. Would it be worth it to upgrade the rocker arms or even the heads to AFR or TF or should I just run my 243s?

 

What kinda power you are you looking to make?

 

Definitely under 1000. Probably 800-850ish as it’s mostly a street car.

 

I would run stock rockers but you could upgrade the trunnions, I did.

TFS heads have a thicker deck over stock.

 

Stick with OEM...Guys have been making that kind of power on stock heads and rockers for years.

 

A decent in between (cost wise) is new LSA heads, I think still about 1200 for a pair.

 

At that level leave it alone with the current heads if your compression level is ok for the fuel you will use. The YSI will not build much boost down low so the boost will ramp in progressively and be easier on things making more power up top.

 

I'd ask BES who ported the heads if there is an advantage to going with the TF heads.
Thicker deck and a better port would be curious to see what the difference in flow would be if any or if there is a gain.
TF heads and stock upgraded rockers get my vote.
Stock 243 port is 200 cfm, TFS 220 if you stay cathedral, they have other options, this was just a quick search.

 

Two prominent LS guys in the power adder world basically said the same thing to me, that stock 243 heads and TFS 220s won't show much of a difference in power on my LC9 but the thicker deck of the TFS heads would be nice if I try to make 1200 reliably.

To the OP's post, I made 750rwhp with a YSI and a low compression 5.7 years ago and it went 9.40@145. That was about 17 lbs of boost off the transbrake. I had LS6 heads on the engine.

 

So basically my opinion here is under 1000rwhp you can stay with stock head square ports or ported cathedrals. Over 1000 rwhp look at going aftermarket and seriously lean towards 6 bolt stuff. Of course same time I would look at an aftermarket block too. If your staying around 850ish rwhp. Ported stock heads and bushed stock rockers are fine. Of course running the tfs heads sooner won't hurt but why spend huge bucks on it unless your going 6 bolt. Just my opinion.

 

This is exactly what I did, I got mine for 594 a piece, I'm using them over the stock 317 heads my lq4 had on it.

They flow similar to a set of ported 706 heads, but I can always port them later which means they fill flow a BUNCH of air.