LS3 Cam Selection

[v8 stingray]

Hi Guys,



Just working on the shopping list for the new LS3 swap into my '73 TransAm and wanted to get your advice on the best cam to use. My builder is suggesting the use of the CompCams Hydraulic Roller 146-460-11 LSR. Anyone got any real hand experience of this in an LS3?

Shopping list below ( tax man here in Europe will be happy with this! )

Part	Link	Cost
Pistons	https://www.summitracing.com/int/parts/man-596265c-8/make/chevrolet	$793.99
Main Bearings	https://www.summitracing.com/int/parts/cle-ms2199h	$136.99
Rod Bearings	https://www.summitracing.com/int/parts/cle-cb663hnk	$17.99
Camshaft	https://www.summitracing.com/int/parts/cca-54-460-11	$389.99
Roller Lifters	https://www.summitracing.com/int/parts/cca-15956-16	$544.99
Pushrods	https://www.summitracing.com/int/parts/cca-7955-16	$140.99
Rockers	https://www.summitracing.com/int/parts/cca-19028-16	$524.99
Valve Covers	https://www.summitracing.com/int/parts/hly-241-402	$279.95
Head Gaskets	https://www.summitracing.com/int/parts/nal-19170419	$152.00
Head Bolts	https://www.summitracing.com/int/parts/arp-134-3610	$101.99
Headers	https://www.summitracing.com/int/parts/hed-45123	$696.99
Starter	https://www.summitracing.com/int/parts/pwm-9509	$217.99
Water Pump	https://www.summitracing.com/int/parts/mor-63566	$476.99
Plug Leads	https://www.summitracing.com/int/parts/acc-9070c	$110.95
Oil Filter	https://www.summitracing.com/int/parts/nal-12626224	$15.99
Spark Plugs	https://www.summitracing.com/int/parts/ado-41-101	$55.92
Fluid Damper	https://www.summitracing.com/int/parts/ati-918628	$436.00
Clutch	https://www.summitracing.com/int/parts/acl-t2r-g05/overview/model/acl	$1,060.00
EFI System	https://www.summitracing.com/int/parts/fif-72213	$2,140.00
Radiator	https://www.summitracing.com/int/parts/bci-10010	$329.99
Wiring Harness	https://www.summitracing.com/int/parts/prf-20112	$949.99
AN Fitting's/Plumbing Fuel, Brakes, Coolant, Power
Propshaft
Stainless Exhaust System
Hardware/bolts/nuts/washers/rivnuts/cable ties/
Mufflers	https://www.summitracing.com/int/parts/flo-8043041	$179.90
Rear Axel & Pinion Gearing	https://www.summitracing.com/int/parts/yga-24161	$309.40
Front Disc Brakes	https://www.summitracing.com/int/parts/wil-140-10738-dr	$1,074.99
Rear Disc Brakes	https://www.summitracing.com/int/parts/wil-140-9315-dr	$864.99
Brake Booster	https://www.summitracing.com/int/parts/sum-760166	$137.99
Master Cylinder	https://www.summitracing.com/int/parts/ssb-a0469-5	$395.99
POWDERCOATED HYDROFORMED SUBFRAME - (1970-81 CAMARO / FIREBIRD - SINGLE ADJUSTABLE SHOCKS - SBC / LS)	https://www.detroitspeed.com/powderc...d-032014-group	$8,684.00
DETROIT SPEED, INC. QUADRALINK™ REAR SUSPENSION KIT - (1970-81 FIREBIRD - SINGLE ADJUSTABLE SHOCKS)	https://www.detroitspeed.com/detroit...d-041714-group	$3,380.00
Subframe Connectors	http://www.globalwest.net/1970-1971-...obal-west.html	$259.95
	LS Swap Kit?	$1,995.00
Electric Fans	https://www.summitracing.com/int/parts/spu-ix-30102049	$303.12
Power Steering Pump	https://www.summitracing.com/int/parts/hly-198-100	$294.00
Power Steering Tank	https://www.summitracing.com/int/parts/mor-63788	$135.99
Power Steering Pulley	https://www.alpermotorsports.com/index.php?l=product_detail&p=181	$94.00
Clutch Pedal Conversion	https://www.classicindustries.com/product/1973/pontiac/firebird/parts/kw328.html	$89.98
Master Cylinder Kit	https://www.summitracing.com/int/parts/awr-hmgm30001sr	$403.99
Slave Cylinder	https://www.summitracing.com/int/parts/nal-24237634	$194.99
Stealth Fuel System	https://www.summitracing.com/int/parts/aei-17168	$1,177.00
Air Filter	https://www.summitracing.com/int/parts/knn-ru-3102hbk	$60.99
Shifter	https://www.summitracing.com/int/parts/baa-2010bc-2bv8	$285.00
Air Con System	https://www.vintageair.com/surefit/complete-kits/?make=Pontiac&year1=1973&model=Firebird	$1,480.00
CVF LS Engine Serpentine Kit	https://www.cvfracing.com/chevy-ls-engine-serpentine-kit-ac-alternator-power-steering/
Electric Cut-outs
Electric Window Kits	https://www.mattsclassicbowties.com/...ndow_Kits.html
Glass Set	https://www.classicindustries.com/product/all-years/pontiac/firebird/parts/*e355t.html	$627.00
Bonnett Hinges	https://www.mattsclassicbowties.com/contents/en-us/d2319.html
Wheels		$4,700.00
Body bushings	solid, rubber or poly
		$36,702.95

[andrewb70]

I guess the first thing I would want to know is the compression ration, and the second thing would be how the car is going to be used. The cam that your builder suggesting is pretty wild, personally I would never use it in a street car, but people's tolerance for big cams vary quite a bit. I tend to like milder cams because they make for a nicer driving car and are easier to tune.

For what it's worth, a friend of mine purchased the LS3/430, then added the BTR racing Stage 2 LS3 cam with the suggested valve springs and pushrods. The engine is installed in a 1966 Farilane and weighs about 3900 pounds. The car has run a best of 11.65 at the drag strip. It is a beast, and drives really nice.

Andrew

[v8 stingray]

I always liked a bit of wild!

Its calculating out at 11.57:1 at the moment... its got 821 heads on the block.

I guess its all about the brief.... told him I wanted something with lots of power, but something that I could equally drive long distances to shows without having a massive headache!

Its initial figures at the moment - but getting feedback from others is all part of the process and trying to get a sense if it is just a bit "too much".

[andrewb70]

For me, it is definitely too much, but others may have different opinions.

Andrew

[Tweak]

I have that exact camshaft on my 408.

Its awesome, accelerates very hard

[andrewb70]

I have that exact camshaft on my 408.

Its awesome, accelerates very hard

A 408 is not a 6.2L...lol

[68Formula]

I have that exact camshaft on my 408.

Its awesome, accelerates very hard

Displacement plays a big role on a cam behavior.

OP, what is the max rpm that you plan on shifting? Are your heads ported or stock (do you have the head flow values)? What's your transmission are you using (hopefully it has overdrive with those 4.56 rear gears)?

[Z06vet]

I agree it's a tad on the radical side. If you end up sticking with that fitech system, I'd definitely go smaller on the cam. I have not run one personally, but know guys that have and the ones with big cams had some annoying issues. With that intake & cam, it will want some gear- at least 3.90/4.10 range. What trans are you running? I would personally step it down just a bit. I'd rather see you CNC port the heads and go with something closer to a stage 2 cam. I'm really picky about driveability though.

[v8 stingray]

For me, it is definitely too much, but others may have different opinions.

Andrew

I guess there's no right nor wrong... it would be great to drive the car with the two cam options and decide, but in the absence of that I'm just going to have to decide a route. When you say you think its too much, do you mean from a drive-ability perspective? It would be really useful to know the cons of such a cam with regards driveability (not sure what a cam like that does to idle etc).

[v8 stingray]

Displacement plays a big role on a cam behavior.

OP, what is the max rpm that you plan on shifting? Are your heads ported or stock (do you have the head flow values)? What's your transmission are you using (hopefully it has overdrive with those 4.56 rear gears)?

Good question... I'm not really going to be driving this at the top-end, so low-down grunt & acceleration are the primary points. Shifting RPM, havent really thought of that to be honest - but like I said this isnt a track-day car, something more with the "wow" factor that I'll drive weekends and take to shows. I'm guessing max shifting RPM is going to be the 6,000-6,500 range. Heads will be stock, and I've purchased a new Tremec TR6060 transmission for the build.

[v8 stingray]

I agree it's a tad on the radical side. If you end up sticking with that fitech system, I'd definitely go smaller on the cam. I have not run one personally, but know guys that have and the ones with big cams had some annoying issues. With that intake & cam, it will want some gear- at least 3.90/4.10 range. What trans are you running? I would personally step it down just a bit. I'd rather see you CNC port the heads and go with something closer to a stage 2 cam. I'm really picky about driveability though.

What's wrong with Radical??

Not stuck on the Fitech system. In fact, wanted to run the Edelbrock LS3 Crossram intake but builder reckons we will need a different system to drive those twin throttle bodies. I'm in Ireland, so CNC porting these type of heads isnt something thats readily available - I'd probably have to ship to the UK to get that done. Noted the transmission below (new Tremec TR6060). I am a bit concerned about driveability now, so glad I asked for opinions!

[68Formula]

Good question... I'm not really going to be driving this at the top-end, so low-down grunt & acceleration are the primary points. Shifting RPM, havent really thought of that to be honest - but like I said this isn't a track-day car, something more with the "wow" factor that I'll drive weekends and take to shows. I'm guessing max shifting RPM is going to be the 6,000-6,500 range. Heads will be stock, and I've purchased a new Tremec TR6060 transmission for the build.

Then you definitely want something else. First of all, the LS3 heads stock, reach peak flow around .600" lift on the intake side. So any lift above that will only gain a handful of horsepower and push the rpm where it peaks, up higher. And it's already going to be pretty high (7000+rpm) with that duration. Plus even on ported LS3 heads, the flow is almost flat by .600" lift. So unless you plan on supercharging or stroking it, going that big will provide no benefit with a large loss of power in low and mid-range rpm.

If you plan on shifting around 6500rpm, then Comp 146-458-11 would be a better choice. Peak hp will be the same as the cam your builder wants to use. If you're really planning on shifting closer to 6200rpm, the Comp 146-456-11 is a better fit. http://www.compcams.com/Technical/Ca.../pdf/page8.pdf Both will sound healthy, but have better driveability, and whoever has to tune this beast will appreciate it . Andrew's suggestion for the BTR cam is a good fit too.

[68Formula]

Which gear set did you pick for the Tremec? With those 4.56s, if you're doing distance then I'm assuming some highway driving (120km/hr), so you're going to want the .50 overdrive to keep things sane. Either the wide ratio set D, or close ratio set F (F probably better with your setup).

Also, to add to the camshaft discussion, be mindful of piston to valve clearances above .600" on that engine.

[Tweak]

A 408 is not a 6.2L...lol

Your a **** lol!!!

[Tweak]

Displacement plays a big role on a cam behavior.

OP, what is the max rpm that you plan on shifting? Are your heads ported or stock (do you have the head flow values)? What's your transmission are you using (hopefully it has overdrive with those 4.56 rear gears)?

Hey
Max shift probably 5k when tune finished. 11.5:1 compression, Heads are bone stock. TKO600 with close ratio overdrive, 3.5 diff gears with 26" tall tire.
We have amazing roads here in NZ, no freeways anywhere close to where i live.

[68Formula]

Hey
Max shift probably 5k when tune finished. 11.5:1 compression, Heads are bone stock. TKO600 with close ratio overdrive, 3.5 diff gears with 26" tall tire.
We have amazing roads here in NZ, no freeways anywhere close to where i live.

OP, what is the max rpm that you plan on shifting...

https://www.webopedia.com/TERM/O/op_...al_poster.html



Also, I have to go with Andrew on the whole 6.2L is not a 408. lol

[Tweak]

Another ****!!!!! Go america!!!!!

[badazz81z28]

I would call Texas Speed. Dyno Proven, in house design cams. They even grind their own now.

[andrewb70]

What's wrong with Radical??

Not stuck on the Fitech system. In fact, wanted to run the Edelbrock LS3 Crossram intake but builder reckons we will need a different system to drive those twin throttle bodies. I'm in Ireland, so CNC porting these type of heads isnt something thats readily available - I'd probably have to ship to the UK to get that done. Noted the transmission below (new Tremec TR6060). I am a bit concerned about driveability now, so glad I asked for opinions!

The Holley Dominator can drive dual DBW throttle bodies and would be an excellent system no matter which cam shaft you choose.

Andrew

[v8 stingray]

The Holley Dominator can drive dual DBW throttle bodies and would be an excellent system no matter which cam shaft you choose.
Andrew

That looks like a nice setup - you used that before Andrew?