I know alot of you are making 400 or more with Vortec heads and a variety of cams. My Vortec's are being ported (chambers, guides, and runners redone). Is the GM Hot Cam Kit with 9.75-1 compression and a Holley Street Avenger 770 carb going to put me anywhere close? Any suggestions would be greatly appreciated.

Well first off how much hp do you have now? all the porting and what not should help, i know that the cam makes a good power increase on lower hp engines but im not sure how much good it will do if your already in the 400s. Maybe get a custom grind cam, the carb should be pretty good but im not really up on the carbed motors so dont take my word for it. good luck

I severely doubt your going to get 500 horse with that combo


You didn't list the specs on the cam.The largest cam that GM has in the hotcam kit is .493/.512 lift with 257/269 duration.I don't think that is enough compression to make good power with even that cam.


Just my thoughts.

Stock Bore? I am going to say that it all depends on how well these heads of yours are ported. Car Craft just got about 470 horse out of a Vortec setup ( ported heads) with a Comp Xe 268 or 274 ( can't remember but I'm pretty sure it was a 268) . You are going to have more compression ( about 1 point) as well as a larger cam, so I am going to say that if you heads are ported properly you'll be close to 500 horsepower, probably right around 485-490.

Make sure you use and Air Gap intake and not a performer rpm or Victor, the Victor will cost you a bunch of torque and the performer rpm will cost a bit of both hp and lb ft.

I don't know how much the motor is making currently, it's a
work in progress. The bottom end was just balanced and the porting work is currently under way. I forgot to include the fact I'm using Manley Race Flo valves and an Edelbrock Air Gap RPM manifold gasket matched with the heads. I'm also using a Diamond Stripper windage tray if that makes a difference. My firend built a 383 w/ Vortec heads that made 500 HP to the rear
wheels, but I am not sure my 350 will make that much at the fly-
wheel.

330hp, was that on a 350 or a 383? I didn't know they made that much on a 350. I followed upto 440hp 350, but I didn't know they got more.

The cam lift on the Hot Cam kit I bought is .525/.525. I bought the single pattern cam because I figured after the porting was done to the heads a dual pattern would over scavenge the exhaust. Being the biggest increase is exhaust flow on most heads. I also bought the MSD coil in cap, module and wires for
firepower.

330hp, nevermind. I just went to Car Crafts website and found the article. Almost makes me want to pull my heads after a whole 60 miles on the engine and run through them again!! Almost, but I think I will wait.

It's a pretty encouraging article isn't it. I can't wait to be pulling over 450 horsepower out of a 355. Then I'm either getting a Vortech or ATI Blower for it. We'll see if I can get it over 650 horse, shooting for 700. Not to mention, aside from the paint, it'll be a sleeper with no crap sticking up out of the hood.

What kind of 700 r4 can handle the abuse of 700 or so horsepower and how much do they cost?

I already know I'm going to blow my rearend apart but I'm gonna wait until I do to change it out.

stock the vortecs will support 450...so ported i dont see why they wouldnt support 500 horse...but its all in the combo


my combo is
LT1 shortblock
ported LT4 heads with 2.02/1.60 valves
comps 502 LT1 grind on a 110
GMPP LT4 dual plane intake

im expecting no less then 450