[DonkBoy72]

I have a stock compression gen 6 bbc 454 w/ fully ported gm 390 castings 2.19/188 valves.Herbert solid flat tappet cam 300/310 [email protected] 250/260 570/595 lift 110 LSA 2500-6800 rpm.ProComp Dual plane airgap intake.A worked Mighty Demon 750carb.TH350 2800stall convertor & 4:10 rear gears.The car is a 1972 Impala roughly around 4000lbs.for street/strip use. Any estimates on hp & do you think Im going in the right direction with this setup?

 

[Indiansprings]

I do not think your going in the right direction. With that cam in there your Impala is going to be a slug. Put an Isky 270 Mega, or something mild like it, and you will have a quick car.

 

[Chevelle '71]

You'll probably want to ditch the TH350 too.... TH400 can take more punishment if you are going for big power in a heavy car. IMO

 

[DonkBoy72]

Ive heard that before about that paticular camshaft. What is the specs on that isky 270 mega. What range of duration my cam needs to be in?

 

[pauls72]

230- low 240. You want a lower power band to get that weight moving

 

[DonkBoy72]

Ok what cam would you prefer & is the 750 demon enough carb for this engine?

 

[pauls72]

Would you be willing to do a roller

 

[DonkBoy72]

Yes i would be willing to go roller. The engine hasnt been fired up yet so i can make a quick swap before we start it up.

 

[pauls72]

Not sure of the New part #s but the lunati 231/239 600-600 might be good. Or if you have flow #s and all other info and if its in the budget call Straub.

 

[dirtlips408]

The converter, vehicle weight and compression are far from ideal with the rowdy camshaft. Duration in the high 220 low 230 range would help a ton.

 

[Indiansprings]

Ive heard that before about that paticular camshaft. What is the specs on that isky 270 mega. What range of duration my cam needs to be in?

I think you should be well under 230 deg. @.050 to get your car moving. You said stock compression, 8.0:1??? Even the 264 Mega cam would like to see more compression. Look at the 264 or the 270. This may help.
http://www.iskycams.com/pdfcatalog/2004-05/page60.pdf

 

[nashville beth]

I think you should be well under 230 deg. @.050 to get your car moving. You said stock compression, 8.0:1??? Even the 264 Mega cam would like to see more compression. Look at the 264 or the 270. This may help.
http://www.iskycams.com/pdfcatalog/2004-05/page60.pdf

He's using closed chamber heads so the compression is almost 9-1.

I think a roller like the ZZ502 cam would be perfect. 224/232 @ .550 lift.

 

[pauls72]

I didn't know we were talking 8:1 cr. I also don't know much about those head #s either. Not many shelf cams will give you much power at that cr regardless. If you are looking for 500 hp + then you should think about new heads and maybe pistons

 

[Indiansprings]

He's using closed chamber heads so the compression is almost 9-1.

I think a roller like the ZZ502 cam would be perfect. 224/232 @ .550 lift.

If he is in the 9:0-1 area than I like the 270 Mega grind for sure. The ZZ502 cam would work. It wouldn't be quite as simple as sliding in a simple Hyd flat tappet cam but it would work well.
You (original Poster) would have been quite unhappy with your current setup. I think you will like the power a smaller cam will bring. Its all about the combination. Every component working with the other component. Heads, cam compression, weight, gear ratio etc.....

 

[pauls72]

If he is in the 9:0-1 area than I like the 270 Mega grind for sure. The ZZ502 cam would work. It wouldn't be quite as simple as sliding in a simple Hyd flat tappet cam but it would work well.
You (original Poster) would have been quite unhappy with your current setup. I think you will like the power a smaller cam will bring. Its all about the combination. Every component working with the other component. Heads, cam compression, weight, gear ratio etc.....

I agree

 

[BACK FROM THE DEAD]

Waaaaayyyyy too much cam for that compression ratio (you say stock comp which is like 8.0-8.5:1), and waaayyy not enough converter for the cam.

Ditch the cam and get something more like what's being recommended and it'll probably work well with the converter you already have there.

 

[DonkBoy72]

I looked up the compression on the vortec 454 like i have & it said that is was 9.3:1 & the heads were shave so im thinkn bout 9.5:1 maybe.

 

[kettbo]

Curtis,
When ever local guy "Jeff Donk" comes up with cash, I'll assemble his parts collection for his beast. He keeps listening to people, "Big Cam, etc." I keep telling this up and commer. BIG TORQUE. I have something for him in the 230 range for 9:1 CR