Troy5061

iTrader: (19)

Im thinking I would like to set a goal for my car to run a 6.99 in the 1/8th mile on motor, full weight. Not sure if a FAST 92 and AFR/TFS heads will be enough to do it as that is prime 408ci car territory. Anyone have real world gains going from 243s to AFR/TFS heads as in mph gain or et gain I could really care less about dyno numbers.

My current setup is

383 LS6 with forged internals
10.8:1 static compression
EPS 230/238 cam
stock ls6 intake and TB
hand ported 243 heads
LPP 1 3/4 lt headers
cutout
36lb bosch injectors
racetronix pump and wiring

TransAmcoupe98

iTrader: (10)

I would say yes they are worth it for other benefits such as height deck, valve size, etc. However, I have seen on here a build with worked 243's on a setup put down 503whp through an M6. Nowhere near as common with heads such as AFR/TFS/MAST but it can be done. I think your 1 3/4'' headers will hold you back slightly however. Possibly look into bigger primaries (1 7/8''). I would have also went with more compression like 11:1-11.5:1 You can get your setup into 6.99, Ive seen 346s with fairly conservative setups run 7.20s.

Way2Fast

iTrader: (1)

What is your 60' times?

If your 243s are ported, i would think you have the power and need to maximize the suspension. My old car had portrd stockers and a 221/221 cam with an ls6 intake that went 7.09 in the 1/8th w/ a 1.50 short time at 3450# empty.

30th t/a

iTrader: (51)

I've seen some TEA CNC ported LS6 heads that put out over 500 on 408's. With you already having the LS6 heads, Id really consider a TEA CNC stage 2 port job.
Id also bump the CR to 11.5:1.

Troy5061

iTrader: (19)

If I go with aftermarket heads I plan on bumping the compression to 11.3:1



My best 60' time is 1.65, should be in the 1.60 range once I get a clean run and now that the torque arm is adjusted better. So it should run 7.29s pretty easy with just getting the 60's better. Its going to be hard to get much better than that without going to a huge squishy converter, doing suspension mods I don't want to do like removing the front sway bar and drag shocks or stipping the car down to a rolling gas can. Plus where I live the track isn't the best lol it's not a nicely maintained well preped track like you guys have down in the civilized world.

I know the FAST will help, this car is on speed density and still pulls vacuum at WOT. By 6200 it's all out of breath and the kpa is around 96-97.

Way2Fast

iTrader: (1)

Do you unhook the front sway bar at the track now? Before I did the adjustables up front with drag springs, I would just unbolt the driver side end link. With a 2800 stall and drag radials with only sfcs and lcas it pulled a 1.68.

What is the altitude of the track you run at? The track I mainly run at is like 150' above sea level. Always a factor, didn't want it to seem like I am dissin your ride. But, either way there are a few little things that can belp your times without the l out drag setup

KCS

iTrader: (20)

The OEM castings have their limitations as you go up in cubic inches or RPM and need the larger ports, the castings get pretty thin. The aftermarket castings are good for larger airflow demands and larger ports, and IMHO, better in the hands of a good cylinder head guy rather than in a CNC machine.

Rise of the Phoenix

iTrader: (27)

It's always been said that when you're building a "Naturally Asperated" engine, you always center build around the heads and you always want to buy the best heads you can afford. I don't think that going with properly ported 243's is a bad option, as we've all seen some very impressive dyno numbers and track times with AI, TEA, FTI ported heads, but at the same time, there are many benefits going with an aftermarket casting, like AFR and TFS. I, myself, was contemplating going the ported 243/799 route and pretty much had myself convinced that was what I was going to do, but the more I thought about it, I decided to just go ahead and save the extra coin so I can get a set of AFR 215cc heads. All I can say is do a bunch of research and pick as many people's branis as possible before you decide what you are going to do.

garygnu

what do your current heads flow ? tfs 220 heads $1670,AFR 210 $2300. PRC cast 220 $1700 ,you mite be able to use stock rockers with some of the PRC heads.

Che70velle

iTrader: (6)

There are many great deals on aftermarket castings, as well as GM castings, right here in the classifieds!

intenseblue

iTrader: (1)

The most consistent results I have seen for BADASS track times have came from Cartek 243 heads with TEA a close second. I can't imagine going from either one of those two to AFRs or Trick Flows and gaining more than a tenth if any at all.

Engine_HP

iTrader: (1)

My tea tfs is worth every cent, i made 470/430 on a stock bottom ls1

Troy5061

iTrader: (19)

Not sure what they flow, a little more than in stock form I'm guessing. They are just low milage 243 heads with the bowls and short side cleaned up.

I think thats the route I am going to go, I guess PRC has some aftermarket heads for $1700 too. I just don't really want to spend the money and take my new motor apart for minimal gains. I guess between bumping compression to 11.3:1 and the extra flow it should be worth it, especially with more displacement. I think the LS6 intake and TB are whats really holding the motor back right now, maybe I'll try that first.

Mike Morris

iTrader: (55)

I think if you can afford it the AFR,TFS will work better since you have come cubes. Keep in mind you will need aftermarket rockers and may gain some weight in the front.

Troy5061

iTrader: (19)

I have stock rockers right now with the trunion upgrade, AFRs are compatitible with them correct? This is one of the reasons I'm leaning towards AFRs.

Rise of the Phoenix

iTrader: (27)

Yes they are. If you comb through the classified section, you can typically find a great deal on used AFR heads. Going this route would be less expensive than buying 243/799 heads and paying someone to port them.

Troy5061

iTrader: (19)

Yea thats what I'm thinking, although I already have 243s

But yea yea if I take the heads off its getting aftermarket castings.

Rise of the Phoenix

iTrader: (27)

You can get $400 + all day long for good 243 heads. Just think, if you find a set of AFR heads for, let's say, $1,600, and you sell your 243's for $400, hell, you really only paid $1,200 for a set of bad *** AFR heads. There are a few sets of AFR and TFS heads I've seen for good deals. Another guy has a set of ETP heads for sale. Some say they are even better than AFR and TFS.

Mike94ZLT1

iTrader: (3)

AFR heads have bronze valve guides and they will wear much faster with a stock rocker...

vettenuts

iTrader: (4)

Also, keep in mind AFR and other aftermarket heads have more valve drop than the GM castings so you may be able to run more cam/compression without fly cutting the pistons.