1bigoldman

First off forgive my ignorance. This is my first LS motor.
I bought a LS1? from an '04 Corvette.
I have identified that the block is 12561168 which appears to be a LS6 block?
The heads are 12564241 appears to be LS1. Which should be 66.7cc opposed to the LS6 heads with 61.1cc chambers and "D" shaped exhaust ports.
The intake is LS6. The TB has LS1 right on top of it.
What cam is this going to have in it? LS1 PT#12561721? or LS6 PT#12565308?

This is going in my '63 Nova with M6, 9"/3.50, TCI suspension front and back, LT headers, and cold air intake. Plans for now are to just get it assembled and on the road. But I would like to know what I got in this motor.

What kind of HP/TQ can I expect from this motor?
If it has the LS1 cam what can I expect for gains if I change out for the LS6 cam?

TIA,

Dhamen

82cetuner

iTrader: (9)

You sir have a 2004 LS1 engine.

after 2001 GM ran out of ls1 blocks and started using LS6 blocks for all there ls1s, this is why you have a ls6 block, LS6 blocks are cast to be a bit stronger and have pressure relief valves between the pistons thats the only difference, no real HP gains.

you have a LS6 intake because after 2000 GM switched over to the LS6 intake on ALL ls1s but drop the cam size to keep the HP the same.

the only 2 REAL differences in a LS6 engine and a LS1 engine are the Heads and the Cam that is where the HP difference is.

241 heads are LS1
243 heads are LS6

your ls1 will probably generate 350 or so HP. the 2004 ls1 cam is VERY small its smaller than the Pre 2000 Ls1 cams. switching to a ls6 cam will probably give you have 25 30 HP, switching to the heads would give you about another 30 and put you right around the 405 hp rating the LS6 had,

If you are going to do a cam swap GO BIGGER, a 228 duration cam is considered SMALL on todays standers but with one of those cams and 243 heads you will be at 450 HP easy and still drive like stock.

82cetuner

iTrader: (9)

but if you ditched the ls1 heads and cam you would pretty much be starting all over with a LS6 shortblock and would no longer have a LS1 LOL

S8ER95Z

iTrader: (3)

Any solid info about the ls6 heads (243s) giving 30hp? I'm on 241s with an 02 ls6 cam and I just don't see the heads giving me that big of a boost.

82cetuner

iTrader: (9)

thats what alot of people report, the heads and cam together make a easy 50 more than the ls1,

you have to remember the ls6 heads not only flow better but increase compression as well, it is a pretty substatial hp gain

1bigoldman

Thanks for clearing things up for me 82cetuner.

What about using the 799 heads? I hear they are the same as the 243's without the sodium filled valves? I'm just thinking that they might be easier to find than the LS6 head. What motors run them?
On the cam are you talking about something like the GM "Hot Cam"?

82cetuner

iTrader: (9)

for a cam i would check out texas speed a sponser on here, if you want to stay mild but make good power there 228/228 duration cam has had great results, but you can go even bigger and still have it drive great, the lobe seperation has alot to do with the idle quality and the rpm ranges it makes power.

799 heads are 243 heads just the earlier version the head casting is not as good and is alot roupher. they both have the same valves though.

you could even slap a set of 317 heads on it and up the compression even more, the 317s are 5.3 heads, they dont quit flow as good as ls6s but are close and bump compression up even more not sure how much. the ls6 head will give you a 10.5 compression.

243 heads are more common than 799 and you can find them for sale on here all the time. or if its in your budget you can get a cnc set of ls6 heads for about 1000 bucks and really bump up the power. ls6 heads really shine up top as well

dont throw that engine in there stock, you will be happy for a little while but then wish you had done a little bit more.

ViperT4

iTrader: (1)

Don't post here a lot but I did this so I can help. Have a 2004 GTO, so probably the same motor you're starting with. Don't have dyno numbers, but I'm fairly certain it was making the stock rating of 350 hp, and 365 tq, with the only mod being K&N and cat-back when I bought it. Maybe a little bit more.

243 heads can be found on Z06s and LS2 cars. The only thing that makes them LS6 heads are the sodium filled valves. I bought used heads off an LS2 goat and put them on at the same time as headers. Final dyno numbers were 351 rwhp and 361 rwtq. Figure 85% drivetrain loss for a manual and that puts me at 413/425 at the crank, gains of about 60 hp and tq.

Kooks headers are advertised anywhere from 20-35 rwhp gains over stock with a tune. My remaining 30 or so hp had to come from the heads. It was probably more like low 30s headers, high 20s from the heads.

The only way I can see switching to an LS6 cam from an LS1 is if the motor is out and you can get one cheap (and beleive me, I thought about doing this too). It really would not be that bad a job with the motor out of the car, especially if you're putting on heads too. Otherwise, I say don't waste your time, go bigger or be happy with what you've got. 243 heads are one of the best things you can do for an LS1.

SOMbitch

iTrader: (8)

In reality untouched 243's are worth about 20. The LS6 cam another 15 or so.....

S8ER95Z

iTrader: (3)

I got the ls6 cam and valve train for dirt cheap and did the swap in the car. Wasn't as bad as many people seem to think. Longest part for me was replacing the oil pump o-ring. My ls1 made 324rwhp/341rwtrq with an FRA and paper filter.. Just don't see the heads giving me a huge boost unless the cam was worth nothing and so far without a tune I gained a decent about of power already.

Stock 13.19 @ 108.59 on 2.1 60ft
Current 12.88 @ 110.17 on 2.0 60ft

Just would like to see actual proof/results from someone that has been down this path instead of guesses and what people think the gains should be. If that makes any sense?

ViperT4

iTrader: (1)

I do know what you mean and in a perfect someone would have it for you. My place was busy so it didn't get a before parts dyno, only after parts before tune and after parts after tune. Do you really think I gained more than 35 hp from 1-3/4" headers on an otherwise stockish 5.7 motor? Even at that, that means the heads were good for 25 hp.

S8ER95Z

iTrader: (3)

Well just for my experience around GTOs their stock tune seems to be lacking.. I had a friend who gained 30rwhp with a tune alone... In stock form his car was a pooch... Just don't want to dump a ton of money for heads and only see a little gain. My cam swap was a whole 200.00, would rather spend money on headers if the heads are not going to bring a massive gain.

ViperT4

iTrader: (1)

True, depends what they'll cost ya. I got mine complete with valves/springs/etc. for $325. Only had to change over the rockers.

S8ER95Z

iTrader: (3)

Wow that's a good deal, if I could find them that cheap I would pull the trigger.