Gray86hatch

iTrader: (83)

My hand ported ls3 is holding me back. The power is flat from 6200 to 7500 where we quit pulling it.
I have the best small block na racer in the country that helps me with ideas. We were on his Dyno and help told me it needs more cylinder head and cam. I have limitations on the cam that keep me from getting crazy.

I would have a set of 305 next week if I had $5000 to spend.

The only way I would have a Holley high ram is if it had two 4500 tb on it. But it will not fit under a hood I can see over.

compare apples to apples

Tim

Briou

iTrader: (1)

So in comparing the 305's to the 285's what is the expected difference in power, and where will each head make the best power...lets keep in mind that I am not focusing this build on peak hp.

BOLO

iTrader: (40)

What engine set up would benefit with a Holley Hi ram and what set up would benefit with a carb type 4500 intake?

Briou

iTrader: (1)

There is a ton of info out there....trying to keep this thread focused on my build but I am sure the guys in here could point you in the right direction...

Ed Curtis

Yeah - what would Charlie know. BBR has more Hot Street and Pro Stock wins than anyone on here.

BTW - we can go solid roller and more porting you know.

Ed

Briou

iTrader: (1)

So what could be expected as far as difference in performance between these two heads?

Briou

iTrader: (1)

Got the ls7 rockers and trunnion upgrade on their way....

Still looking for some info on the difference in performance between the 285's and the 305's

Brian Tooley Racing

iTrader: (13)

Charlie is a top notch racer, but Charlie doesn't port heads that I know of? Kuntz does them for him.

Kuntz is probably the best guy in the country with Hot Street heads, but not with hydraulic roller heads?

The fastest hydraulic roller cam'd LSX in the country has "little" TFS 245's on it and has run 8.92 @ 150 on motor, no power adders. He's #10 on the fastest N/A list.

10) 8.92 @ 150.50-- 430in-- Coleman Roddy-- 3070#-- Hyd-- T/F Cathedral

If the "biggest" head always made the most power and ran the fastest, then why doesn't NHRA Pro Stock use the biggest heads they can find?

I'm not disputing that Tim's heads are holding him back, but it's not because they're not BIG enough, it's because they're not EFFICIENT enough.

If more hydraulic roller guys would take what a cylinder head flows at .300"-.500", plug those numbers in to a coefficient of discharge calculator, and then develop the smallest port they can with the highest C of D numbers, then they would have FASTER heads.

Gray86hatch

iTrader: (83)

Charlie knows his way around his engines better than Jim does. Jim ports the heads and build the engine. Charlie gets the most out of it.

A engine that has to go down the road without chewing up parts is different than something that has to last 100 passes.

Like I said if I put a much more aggressive cam in it and turned it harder more compression it would run better.
That stuff is not a option so the heads have to be better.

Apples to apples

Tim

Brian Tooley Racing

iTrader: (13)

Coleman's cam has .625" intake lift.

You don't have to run .700+ lift to make good power with a hydraulic roller cam.

We turn these types of cams 7800 RPM with stock rockers and don't chew up any parts.

Brian

Briou

iTrader: (1)

Thanks for the input guys...

So Brian, I will make more power with the 285's as opposed to the 305's? I won't mind having an "aggressive" or "big" cam, as the ITB should make a more agressive cam seem more mild on the street from what I have been able to figure out.

Brian, would you be able to expand on the coefficient of discharge calculation? Being a mechanical engineering student I am very interested in the engineering behind stuff like this...

Hopefully I can get a job in the automotive world for when I graduate in May.

Thanks again for the input!

Brian Tooley Racing

iTrader: (13)

Airflow/curtain area = Coefficient of discharge

Curtain area is simply valve diameter times pi

We strive for minimal C of D at .100" lift but for a hydraulic roller street car we want maximum C of D from .300"-.500"

This is why heads like the TFS 225 made for a 4" bore ended up with a 2.055" intake valve as opposed to a 2.08" like our competition was using. The smaller valve actually flowed more air at .400" than a 2.08" valve. When a larger valve flows less air at .400" lift it's a double loser for a street head. The TFS 225 heads seem to consistently make great power on 4" bore LS2 engines. In back to back engine dyno testing the competitors heads with 2.08" valves were 20 hp behind the TFS 225 heads with the smaller 2.055" valves.

If the 305 heads have a larger intake valve than the 285 heads, but flows about the same through the midlift, then I'll take the 285 heads 99% of the time. With the exception being when a large shot of nitrous is being used. Nitrous displaces air so more port volume is needed.

Briou

iTrader: (1)

Man that makes allot of sense...Thanks for the explanation..

I am definitely not going to do any nitrous any time soon so it looks like the 285's are going to be my best bet, like you have told me multiple times haha...

Is there any benefit to doing any port work or polishing on the 285's?

Briou

iTrader: (1)

I got my trunnion upgrade kit from a member, and I should have a set of ls7 rockers here early next week, also from a member...Now it is just a waiting game until I have the money to get the head castings, valves, spring kit, etc.

Here are my plans as of now for the heads.
-Mast 285cc Bare heads
-Titanium Intake Valves
-Inconel or Hollow Stem Exhaust Valves
-BTR PAC .700" lift spring kit with Ti Retainers

As for the other parts I need...
-Some sort of link-bar lifters, thinking either Morel or Isky
-3/8 chromoly pushrods
-Comp LS3 Hex-A-Just timing set
-LS3 Timing Cover
-Oil pump....Debating between Melling 10296 and 10295, or a ported LS6 pump
-Custom Ground LS3 Cam....Specs to be determined
-ARP Head Stud Kit

And finally a new set of sensors
-Cam Position
-Crank Position
-2 Knock Sensors
-Oil Pressure
-Coolant Temp
-Map
-IAT

So is there anything I am forgetting here?

Briou

iTrader: (1)

Any input here guys?

Briou

iTrader: (1)

Getting to the point where I can start buying some more head parts...Looking at buying a set of springs next...thinking of the BTR .700 lift springs....Do you have any input on this Mr. Tooley, or anyone else....??

Brian Tooley Racing

iTrader: (13)

I assume you're talking about the .700" lift PAC 1207X spring kit that we offer for $399?

Here's a video of them in action, 7500 rpm out the back door!

Briou

iTrader: (1)

Yes! Those are the ones I am talking about...I don't think I will have a cam pushing more than .700 lift so I think I will be safe with the .700" lift springs...

Dyou have any input on lifters? Thinking morel or Isky...

Brian Tooley Racing

iTrader: (13)

We've had issues with practically all of the lifters we sell.

On a percentage basis we've had the least issues with the GM LS7 lifters. Maybe that's because when someone has an issue they don't call so therefore we don't know.

We've had the most issues with the most expensive lifters we sell, that may be because they get scrutinized to death.

We're currently looking at the Johnson link bar lifters hoping the quality will be 100% consistent. Evidently that's what GMPP is using on the COPO cars.

mebuildit

Have you looked at Jesel's? I know that they are expensive, but might be worth checking into.