input on this setup

[USMARINE1108]

So this is the setup I'm thinking about, I know a guy making 457rwhp (also has a ported throttle body, and a pully) with the same heads, but a little smaller cam. AS 5.3 heads, and FM13cam. The heads are 11-1 compression, 2.02/1.575 valves, and flow 314 at .600. Cam is 230.8/233.1 .598/.588 on a 112+4. Should put me around 420-440rwhp. That is without the pully and throttle body, which will be comming soon too. Any suggestions/input on this setup? thanks.

[USMARINE1108]

Anyone?

[Crawlin]

go with what works. alot of info and alot of information out there. I don't think any Absolute Speed heads are available anymore after that **** up that's been posted.

but again, you can get a good idea of what's out there and what works. there's SO many possible combinations. yours a 6speed? his a 6speed?

[BAD LS1]

Yell ya what... if you want real world #s... I had stg II 5.3's on my car, with a cam similar to that, with a pretty spot on tune... it made 390rwhp and 375 tq, but the car went mid 11's @ 120 weighing 3400 lbs?!?!?

I had no little black magic up my sleve like some of these people do to get these over the top #s, there is always some vital detail left out...

IMHO, for stock CI stay with your stock heads with that big of a cam. I never got to dyno my car this year or run it yet, but i tell ya what, it felt like it picked up 20 hp under the curve with the stock heads back on it and was over all more snappy.

Save your money, heads are all smoke and mirrors on stock CI engines, the only way they give a real increase in power is if the factory heads are complete garbage, which the LS1 heads are not.

BTW!! that 457... thats PEAK not continious... that car is prolly such a turd under 3k, who wants something honda like that needs to be wound over 5K before it feels like its moving anywhere?

Run that cam, good comp 921 valve springs, and chromoly .080" push rods.

[HITMAN]

IMHO, for stock CI stay with your stock heads with that big of a cam. I never got to dyno my car this year or run it yet, but i tell ya what, it felt like it picked up 20 hp under the curve with the stock heads back on it and was over all more snappy.

Save your money, heads are all smoke and mirrors on stock CI engines, the only way they give a real increase in power is if the factory heads are complete garbage, which the LS1 heads are not.

Tom, I disagree with you on one point. Just because something feels quicker or faster with snappier throttle response doesn't always make it so. Two different times on separate engines I've fallen for the "higher lift, shorter duration = broader power band/quicker et/better mph" school of thought and twice I've been burned with a car that felt snappier/quicker/faster but the results at the track proved the opposite. You can't make a blanket statement like "Save your money, heads are all smoke and mirrors on stock CI engines" without some empirical data to back you up. The "butt-cheek" dyno is the most notoriously unreliable testing device there is. It's too subjective. The mind is easily tricked and even the most experienced racer can still be fooled. The dyno and, more importantly, the race track should be your guide as to what is REALLY going on.

I'm not trying to start an argument, I'm just throwing in my $.02 based on my experience.

[BAD LS1]

Tom, I disagree with you on one point. Just because something feels quicker or faster with snappier throttle response doesn't always make it so. Two different times on separate engines I've fallen for the "higher lift, shorter duration = broader power band/quicker et/better mph" school of thought and twice I've been burned with a car that felt snappier/quicker/faster but the results at the track proved the opposite. You can't make a blanket statement like "Save your money, heads are all smoke and mirrors on stock CI engines" without some empirical data to back you up. The "butt-cheek" dyno is the most notoriously unreliable testing device there is. It's too subjective. The mind is easily tricked and even the most experienced racer can still be fooled. The dyno and, more importantly, the race track should be your guide as to what is REALLY going on.

I'm not trying to start an argument, I'm just throwing in my $.02 based on my experience.

I completely agree.

However my actual race track testing proved those heads gained .2 and 2 mph over the stockers, how knows it may have been the slight increase in cam at the same time that gave the diff.

It maybe my closed minded opinion, but on an LS1 the stock heads go along ways before the need for replacment in favor of higher flow units, espeically a bolt on car.

The reason mine had a gain on the "ass dyno" i feel is because i use such a massive cam, .595"/.595"-237/242 112LSA that the increased port velocity from the smaller intake ports help to boost that low end feel over the ported heads last year on the same cam. My statement basically says i noticed a gain in "feel" under the curve which made the car more pleasureable in the driveability dept.

Anyone can purchase whatever parts they wish, its their time and money, but 20 rwhp isnt worth 2K to me...

For arguments sake,the same heads and cam that came off my motor made 5 more rwhp than mine with a speed inc dyno tune on a 100K mile motor, the diff is probably the 10 bolt rear vs 12 bolt... So my tune wasnt far off thats for sure and leaves that out of the question, which i performed using the ass dyno method and wideband o2 sensor

[HITMAN]

However my actual race track testing proved those heads gained .2 and 2 mph over the stockers, how knows it may have been the slight increase in cam at the same time that gave the diff.

Or maybe not. Without a cam change or two, you can't really say for sure you had the ultimate cam for that head and vice versa.

It maybe my closed minded opinion, but on an LS1 the stock heads go along ways before the need for replacment in favor of higher flow units, espeically a bolt on car.

Yes, they do flow flow very well in stock form. But from flow sheets I've seen, the port also stalls early (beyond .550 lift). Most of these "cam only" guys use a cam with such high lift numbers that it actually starts to hurt air flow at some point.

The reason mine had a gain on the "ass dyno" i feel is because i use such a massive cam, .595"/.595"-237/242 112LSA that the increased port velocity from the smaller intake ports help to boost that low end feel over the ported heads last year on the same cam. My statement basically says i noticed a gain in "feel" under the curve which made the car more pleasureable in the driveability dept.

Massive? I guess massive is kind of a relative term. Massive, to me, is a cam over .800 lift with .050 duration beyond 300*. That Popsicle stick you're running has some decent lift, but it's pretty short in the duration dept. I've come to find that lift doesn't have as much to do with power as does duration. Which leads me to my next point: There is such a thing as too much velocity. Once the air flow through the port becomes supersonic, the port will stall and, in some cases, even fall off. The only way to slow it down and extend the power curve is to add duration. If you really want to maximize the power from a cam only set-up, I suggest you have the heads flowed and have a cam ground accordingly, based on your needs and wants.

As I said, I've replace existing cams with others that felt way faster just driving around, but were, in fact, slower at the track. I guess it all depends on your priorities. Where do you want the car to shine?

Anyone can purchase whatever parts they wish, its their time and money, but 20 rwhp isnt worth 2K to me...

As I said, you have to figure out where your priorities lie. To most, that would be a waste for 20hp. But to an NHRA Pro Stock engine builder, he'd probably kill for 20rwhp that came that cheap. It's all based on perspective...

[USMARINE1108]

Anyone can purchase whatever parts they wish, its their time and money, but 20 rwhp isnt worth 2K to me...

Ha, it's kind of funny you say that. I wasn't even going to get heads at first, for that exact reason. I'd rather put 2K into a 12 bolt, cluch, throttle body, pully, curb feelers, whatever. But I'm getting such a good deal on these heads, it would be stupid to pass it up.

[BAD LS1]

Ha, it's kind of funny you say that. I wasn't even going to get heads at first, for that exact reason. I'd rather put 2K into a 12 bolt, cluch, throttle body, pully, curb feelers, whatever. But I'm getting such a good deal on these heads, it would be stupid to pass it up.

After you buy them, there is always LS1tech.com's classified section...

$$$$

I'd rather put 2K into a 12 bolt.

Ahhh yes the F-body racing tax... Wise choice!

[USMARINE1108]

After you buy them, there is always LS1tech.com's classified section...

Yea, that's what I was thinking too. But I'll most likely use 'em for awhile, and see what they're like. The heads are kind of the reason for me asking this question, I just wanted to get some opinions on them.