243 Goat Heads

**OnEbAdReDSS** · 07-27-2008, 10:24 PM

Will they fit a LS1 head? I got a good deal going down if they do!

**OnEbAdReDSS** · 07-27-2008, 10:34 PM

Bump for Morning Crew

rednari · 07-27-2008, 11:08 PM

Yes. But check your pushrods for correct length.

**DocEwww** · 07-28-2008, 03:52 AM

Yes.

Originally Posted by rednari

Yes. But check your pushrods for correct length.

Won't matter, same size vavles. They're not LS6 vavles.

**Frost** · 07-28-2008, 05:46 AM

they will make very little power over the stock heads with the stock cam, ESPECIALLY if you still have an LS1 intake (I can't remember

)

**OnEbAdReDSS** · 07-28-2008, 06:05 AM

well here you go... im going to be putting bigger valves, bigger cam in the car and i have a ls6 intake... and will putting the works like spring works on the head... now those 243 heads aren't like the ls6 heads?

**9T8W66** · 07-28-2008, 03:25 PM

Originally Posted by OnEbAdReDSS

well here you go... im going to be putting bigger valves, bigger cam in the car and i have a ls6 intake... and will putting the works like spring works on the head... now those 243 heads aren't like the ls6 heads?

243's are LS6 heads. The ones on the 6.0 GTO's just don't have the lighter valves.

**Frost** · 07-28-2008, 06:02 PM

Originally Posted by 9T8W66

243's are LS6 heads. The ones on the 6.0 GTO's just don't have the lighter valves.

that's right.

LS6 heads with sodium filled valves:

**OnEbAdReDSS** · 07-29-2008, 07:40 PM

i want!

**DocEwww** · 07-30-2008, 05:00 AM

243 is the casting number. LS6 and LS2 heads both use this "243" casting BUT have different valves.

Originally Posted by Frost

they will make very little power over the stock heads with the stock cam, ESPECIALLY if you still have an LS1 intake (I can't remember

)

Proven to make ~15rwhp over a LS1 head. Better airflow and a bump in compression.

Its worth the swap if you can find a cheap set. I got mine (before I upgraded) off a 05 GTO whos owner swapped for AFRs.

**Frost** · 07-31-2008, 11:12 AM

Originally Posted by DocEwww

243 is the casting number. LS6 and LS2 heads both use this "243" casting BUT have different valves.

Proven to make ~15rwhp over a LS1 head. Better airflow and a bump in compression.

Its worth the swap if you can find a cheap set. I got mine (before I upgraded) off a 05 GTO whos owner swapped for AFRs.

I have seen more than 1 set on an otherwise totally stock LS1, and if they made anything, it wasn't enough to point out. Both were 6speed cars and both made within the average of other cars with the same boltons, not even the upper end of the average.

If you had something to compliment them like more cam/less crappy intake, etc, I'm sure that they are worth some power.

I'm not going by what I have read though, I'm going by what I have seen when I say this.

**OnEbAdReDSS** · 07-31-2008, 11:57 AM

thanks frost for the info and everyone else im going with 243 heads and getting a cam custom to what my heads are going to be modified to

**juiced99ws6** · 08-02-2008, 03:10 AM

Originally Posted by OnEbAdReDSS

thanks frost for the info and everyone else im going with 243 heads and getting a cam custom to what my heads are going to be modified to

make sure you take them to a decent machine shop and at least get a simple port job done. Also if you go with a nice after market intake get it port matched while it is there. Will make all the difference in the world

**DocEwww** · 08-02-2008, 07:16 AM

Originally Posted by Frost

If you had something to compliment them like more cam/less crappy intake, etc, I'm sure that they are worth some power.

Why does a 02-04 zo6 put down more at the wheels than a 01-02 F body?

They have the same intake manifold....the answer is the heads and cam are improved. Theres no way you're not going to gain ANYTHING from swapping from a 241 casting head to a 243.

**Frost** · 08-02-2008, 07:38 PM

Originally Posted by Frost

I have seen more than 1 set on an otherwise totally stock LS1, and if they made anything, it wasn't enough to point out. Both were 6speed cars and both made within the average of other cars with the same boltons, not even the upper end of the average......

The first one was a few years ago, and I don't really remember what it put it down. About 2 months ago I had a 99 WS6 M6 with LTs and true duals, lid, pulley, and stock 243 heads (stock cam) and LS6 intake. The car made 335rwhp. By comparison, the user here gnictry's car made the same about a month prior. Her car had eBay headers, lid, and catback and made the same numbers... and it was an auto. I had a full boltons car make 338rwhp a few weeks back on the same dyno. It was a 6-speed.

Like I said, if they were worth something with the stock cam, it wasn;t enough to point out.

At a bare minimum get those things milled down. The bump in compression makes power and is cheap to have done.

**glhs377** · 08-08-2008, 01:22 PM

be careful when going to larger valves and big cams with a small ls1 bore. there's interference valve to bore.

or maybe i'm just thinking of the 5.3. it's been a long time.

**DKITCHEN** · 08-17-2008, 05:44 PM

Originally Posted by Frost

The first one was a few years ago, and I don't really remember what it put it down. About 2 months ago I had a 99 WS6 M6 with LTs and true duals, lid, pulley, and stock 243 heads (stock cam) and LS6 intake. The car made 335rwhp. By comparison, the user here gnictry's car made the same about a month prior. Her car had eBay headers, lid, and catback and made the same numbers... and it was an auto. I had a full boltons car make 338rwhp a few weeks back on the same dyno. It was a 6-speed.

Like I said, if they were worth something with the stock cam, it wasn;t enough to point out.

At a bare minimum get those things milled down. The bump in compression makes power and is cheap to have done.

Didn't you tune my friend Russ's Red 2000 TA a few months back too? It's an M6, longtubes, lid, ls6 intake, magnaflow exhaust, stock cam, 243 gto heads and made almost 350 rwhp. Before that you tuned it for a 224 cam when it had stock heads and an LS1 intake and it made around 360 rwhp. Seems like the heads along with the ls6 intake worked pretty well.

**0rion** · 08-17-2008, 06:54 PM

Originally Posted by DKITCHEN

Didn't you tune my friend Russ's Red 2000 TA a few months back too? It's an M6, longtubes, lid, ls6 intake, magnaflow exhaust, stock cam, 243 gto heads and made almost 350 rwhp. Before that you tuned it for a 224 cam when it had stock heads and an LS1 intake and it made around 360 rwhp. Seems like the heads along with the ls6 intake worked pretty well.

why would he pull the cam and do all that work to lose hp though?

I agree with Frost.....the work doesn't justify the minimal gains of simply swapping to 243's. Frost didn't say you wouldn't gain anything, he said what you gained wouldn't be much and I agree with that. If you're doing other things at the same time it would be worth it but not just to swap heads. Save 'em until you can do an intake,cam, and headers and then do all of that at once.

**Frost** · 08-17-2008, 09:24 PM

Originally Posted by DKITCHEN

Didn't you tune my friend Russ's Red 2000 TA a few months back too? It's an M6, longtubes, lid, ls6 intake, magnaflow exhaust, stock cam, 243 gto heads and made almost 350 rwhp. Before that you tuned it for a 224 cam when it had stock heads and an LS1 intake and it made around 360 rwhp. Seems like the heads along with the ls6 intake worked pretty well.

To be honest, I had Russ's car in mind when I made that post, and his did much better than I expected with them. I've had 3 that were pretty disappointed in what they made before him. It was hard to pin down exactly what everything was worth (in his case) since the LS1 intake hurt the 224 setup and the ls6 intake favors the ls6 heads. It definitely was more torquey all around as well with the heads/intake/stock cam. Once an aftermarket cam is put with them, they will be worth more than they are by themselves.

**DKITCHEN** · 08-19-2008, 12:54 PM

[QUOTE=0rion;1603232]why would he pull the cam and do all that work to lose hp though?

He was tracing an engine noise that began after his cam swap and ended up pulling the 224 cam. I was just impressed that his car made the same rwhp with the stock ls6 heads and ls6 intake that it did with the 224 cam only setup. We keep trying to talk him into putting the cam back in now that he has the heads and intake installed. I have a clip of his car idling next to my 98 Trans Am, and Frost had it idling exactly like my bolt on TA.