Another reason why I highly dislike the GMPP CNC LS3/L92 heads. They are probably the poorest performing square port head I've ever worked with.

 

The right out of the box valve job on them looks pretty poor. And they need a little attention. I want the set Speed Tiger has the ls3 darts w/Low lash cam. His car is incredible with a stroked ls2 (ls3 heads). I cant believe he runs 3:70 gears. Doing 5's In the 1/8 down here.

 

Car best is 10.98 @ 127mph...

Well what you guys think ? Me... I think at that horsepower level the car should have a high mph and a better e.t to boot. Otherwise the car makes power.....

 

That's because those power numbers are inflated. Essentially a cam only 416 is not making 535whp through a 9 inch.

ET is slow for the MPH it must leave soft. 127 mph should take you low 10's.

 

The problem is that people immediately think porting=moar horsepowerz. Even further, some people convince themselves that if it comes from GM, then it must be top notch. I mean, GM would never put their name on junk.

 

Idk....that seems aweful strong dislike for a cnc head you can get for $6xx complete. Are there probably better ones? Most likely but for the $ they're hard to beat. A friend has a dirt car and uses them. His dirt ls motor made 740 crank hp with a hydraulic cam. Pretty good imo.

 

http://www.superchevy.com/how-to/ghtp-1205-cathedral-vs-rectangular-port-cylinders-head-to-head/

Have a beer and learn some knowledge

 

But which one performs better at the track...

 

Rectangles are by far the fastest at the track

 

I'd kinda bet that cathedrals would always produce better 1/8th mile numbers cuz of the lengthy roll through first gear. But anytime you have shift recovery that holds the air pump beyond 5500 rpms the bigger square ports will shine

 

Well well well... Brian Tooley said it in another thread. Its basically budget vs speed.

He went on to say I recommend LS3 heads all the time. They the best bang for the buck. No arguments. He even recommend them over the tfs/fast cathedral setup due to cost.

However if the customer wants the best performance and POWER he puts them on a set of TFS/Fast setup. The LS3 heads just dont seem to get the cars down the track as fast.

Then he went on to say if you think LS3 heads maje the power of TFS cathedral heads... you dobt know cylinder heads.

 

But, but, but, numbers on paper say otherwise

 

BTW once we start spending $ it's all a matter of OP. I can say this the Cat* heads do make me think and MAST are $1800 and they look Darn good (the *Cathedral* style heads are Proven street & track ready). I've gotten pass the *Cathedral, *Ls3, & *Ls7 wars as I would like to do another set sometime in the near future yet it comes back to budget so what then? And I do know and Ask alot of ?'s as I don't mind spending $ on heads as I would like another set.. *Best* bang for the buck are Ls3 Factory heads yet once we say aftermarket or spending coin$$$$.oo you do have Choices. A ls7 head is Superior to BOTH and are around the same amount of money when we say we are spending 2k + for heads and there made for all sizes.

So TRUE of a Quote.

 

Why are people in this thread STILL comparing them as cathedral vs rectangle?!?!?

*****BANGS HEAD AGAINST KEYBOARD VIOLENTLY*****

*****THROWS KEYBOARD AND COMPUTER OUT THE WINDOW*****

Now I need a bandaid and a new computer....lol

 

You know what beats cathedrals and rectangle port heads?

Turbos.

 

LOL!!
Well Ray Bulach just went 8.06 @ 181 on cathedrals with a turbo in his 6 speed cam.

 

I seen that. Crazy badass! Imagine how fast he would go with rectangles!

 

Lol. I always say that when I see people running the LS6 intake.

 

My customer Nick McGrath holds the Extreme Street 1/8th mile MPH record with a 265cc "square port" head with a 2.200" intake valve (which some people would say is too big for that combination) at 153mph with a 76mm turbo and 3125 race weight. Will most likely set the Real Street MPH record at BG coming up, and if they can get the chassis bugs figured out hopefully the ET record. They only have 7 full hits on the car, and out of those 7 passes it has spun on 6 of them. The only full pass it made it went 5.01@153 with a 1.35 60' and not bringing in full boost until 2.8 seconds into the run.

Again it's not the SHAPE!!!! It's the AREA!!!!!

 

Ive seen Tooley TFS as cast 220s run 5.0s in the 1/8 mile..... also on more than one setup/car not sure what class they was in tho.

Also don't forget about Mark Koehler, Ohio
Firebird, 7.50@194 MPH
106mm turbo/KUP/ERL hydraulic 441/TFS 245 heads/Edelbrock intake/315 drag radials. According to my calculation thats 4s in the 1/8 mile.