skinny z

Regarding the better than LT4 cam question, I can't comment on better but I can say I had decent results with Vortec heads and Comps XR276HR cam. Built with 10:1 SCR and 8:1 DCR, it required premium fuel although it handled all the timing needed and had excellent street manners. It even managed a 105 mph trap speed in my 3700 lb IROC.

86LG4Bird

iTrader: (1)

Yeah, I would prefer that XR276 over the CC503 suggested by anesthes. Same lobes, except CC503 is 112LSA/108ICL.
The CC503 has been so popular with the LT1 crowd, that many are up for grabs cheap on the classified boards.

anesthes

iTrader: (12)

Me too, but he never answered if it was EFI or not.

110/106 can be interesting trying to tune with a factory ECM.

-- Joe

Orr89RocZ

iTrader: (20)

It would be fine lol i've tuned bigger and they work fine

86LG4Bird

iTrader: (1)

In the LT1 world, it's not a problem with factory OBD1 PCM's. I can't speak for whatever control system he's using.

Orr89RocZ

iTrader: (20)

Its similar but no individual inj fuel offsets and its bank fire.

anesthes

iTrader: (12)

Yup, you've got cyl trims with LT1 and most sequential aftermarket systems. With the stock '165 or '730 ECM from a thirdgen you've got batch fire, very crude 02 feedback, and only two firing strategies which have an arbitrary switching point. A lot of the factory stuff is done in the hardware so you can't manipulate certain things.

-- Joe

anesthes

iTrader: (12)

Using what ECM?

The forum is filled with threads from guys who idle like crap and can't tune it out, or have hesitations on throttle transitions. Then you've got the open loop idle patches which help some folks.

Then you've got people who's stuff runs like crap but think it's cool. Lots of youtube videos of that posted on the forum.


-- Joe

Orr89RocZ

iTrader: (20)

165/730, no issues. Not everyone can do it. Lots of "tooners" out there

al8429

Gonna go with a carb. Fuel system from the 97 vortec motor was shot and most injectors were melted from engine heat and old age. Going in a 80s monte carlo ss. Gonna use the 1406 eddie carb that's on the old motor for now and probably get something else later

86LG4Bird

iTrader: (1)

I'm glad you're not using the L31 induction system. If you did, all this stuff we're discussing wouldn't even matter. The Vortec intake doesn't let anything breathe above 5500 rpm.

al8429

So should I just use the lt4 hotcam or get the xr276?

86LG4Bird

iTrader: (1)

Do you already have the Hotcam? If so, I'd use it. Degree it in at the 105-106 ICL like was discussed earlier, and you'll make within 10-20 hp of what you'd do with either the XR270 or XR276 cams, maybe even more than the 270 cam.
All these guys badmouthing the Hotcam have not used it. Or they never set the motor up and tuned it correctly.

skinny z

Anyone here have the specs for the LT cam? Advertised and .050" numbers. ICL (installed straight up) and LSA

86LG4Bird

iTrader: (1)

Adv: 278/288
.050": 218/228
112 LSA, 109 ICl straight up
.525"/.525" with 1.6's
VERY easy on the valvetrain
It was GM's roadracing cam for some "stockish" LT1 class, thus the late ICL and easy lobes.

anesthes

iTrader: (12)

Nothing wrong with carb. I have a carb in my stingray and it drives just peachy.

-- Joe

skinny z

Easy lobes...certainly. As a comparison, the 276 is 224 @ .050". There's something to be said for that. Not really knocking the LT4 cam other than to say it's pretty old. As for easy on the valve train, that's plain to see.
Now my XFI cam has a 274 adv and 224 @ .050. And we know how those lobes are on equipment (although with my little pedestrian build, the added stresses don't amount to much.

skinny z

X2!

86LG4Bird

iTrader: (1)

X3!

al8429

Thanks alot for the help guys. Are the 1405 carbs good as well?