More power from a crtae motor

[Hawssie]

I hava an older but low to almost no mile either 310 or 330 hp long block GM crate motor. To finish the engine off it has an Edelbrock performer and an Edelbrock made Rochester 4 barrel vacuum secondaries carb on it. Also has an MSD distributor with a 6AL ignition, fancy plug wires, air cleaner and valve covers, headers and a serpentine belt set up. I am running a 4L60E w/ TCI controller that I still need to dial in the shifting a bit. All this stuff except the trans & controller is circa 2000 including the engine. At the time this model carb was being discontinued by Edelbrock and the GM parts guy said it was way better then a typical Holley so I should buy it before they are no longer available (his opinion). It does start,run and idle and respond nice but it doesnt feel all that powerful. I was reading the post "need advice on vortec heads on goodwrench!" and I saw the comp cams 268 cam mentioned and was wondering if this would be a good idea for my engine. Would this cam provide benefit for my engine? Or what else would be a good idea to get it closer to 350+ HP like some of the other guys running Vortec heads etc.?

[geezer#99]

Usually swapping in a different cam only makes your wallet lighter!!
How else is your drivetrain set up?
What's the initial timing?
What rpm does it idle at?
What's the stall on tour tranny convertor?
What rear gears?
How big (tall) are the tires?

[Fitz]

Originally Posted by Hawssie

I hava an older but low to almost no mile either 310 or 330 hp long block GM crate motor. To finish the engine off it has an Edelbrock performer and an Edelbrock made Rochester 4 barrel vacuum secondaries carb on it. Also has an MSD distributor with a 6AL ignition, fancy plug wires, air cleaner and valve covers, headers and a serpentine belt set up. I am running a 4L60E w/ TCI controller that I still need to dial in the shifting a bit. All this stuff except the trans & controller is circa 2000 including the engine. At the time this model carb was being discontinued by Edelbrock and the GM parts guy said it was way better then a typical Holley so I should buy it before they are no longer available (his opinion). It does start,run and idle and respond nice but it doesnt feel all that powerful. I was reading the post "need advice on vortec heads on goodwrench!" and I saw the comp cams 268 cam mentioned and was wondering if this would be a good idea for my engine. Would this cam provide benefit for my engine? Or what else would be a good idea to get it closer to 350+ HP like some of the other guys running Vortec heads etc.?

The motor you have is a docile workhorse intended to give years of service for someone who does not drive hard and is not interested in performance.The magic in any engine is in the heads. Since you didn't post the part number for them there is no way to tell just what they are but the Vortec heads are going to move to a higher compression ratio and flow more air so they should wake that motor up a little. Your Rochester carb is , well, a Rochester. It is not a high performance carb and is more suited to a grocery getter, not a drag racer. It should be the LAST thing you change, however. A comp 268 ( which is a flat tappet cam) will give a rougher idle and widen the power band from 1500 to 5500 rpm but it won't help much with the heads I think you have. To get more out of that engine you will need heads that will flow better then that motor will be able to take advantage of the longer intake and exhaust duration a cam change will give.

[rickpilgrim]

Vortec head is a 30-40 hp advantage over your crate motor heads.
What I build for myself and others is rarely a single pattern cam in a small block chevy as there's more power with a balanced intake/exhaust flow than running the same pattern on both intake and exhaust. To avoid writing a book well say the exhaust needs more help than the intake.
The Lunati Vodoo cam line has some very good choices for sbc in trucks, the first is 10120700LK that is good for a mild street driven motor
Next is 10120701LK which works ok in stock engine but really likes carb intake ign work( which is very close in power to a comp 268 in a stock engine like yours)
And 10120702LK is about the biggest you can run with stock converter and exhaust but works best with other engine mods.
I have ran the vodoo's for yrs in motors and not had a problem. I do always upgrade pushrods and rockers plus springs.

Hope this helps you out

[Hawssie]

THANKS, I got the part off of my block and its 12355345 which is a 330 hp GM crate motor. It has Vortec heads and the carb I am using is a Edelbrock 1903 which is a Rochester 750. And again other then the stiock crate motor it has headers MSD ignition and a 4l60e trans. I looked up the specs on the engine and the compression is only 9.1 to 1. I know this engine is set up of for durability and drive ability for its HP output but this truck isn't a daily driver but it does need to stay reliable. The cam is part number 24502476 Lift: .435” I, .460” E. Duration @ .050: 212o I, 222o E. I have seen 350s make close to 400 hp with stock Vortec heads and different cam but the compression is more like 10 to 1. I am using premium right now. What is the compression that normal 91 pump gas can handle? I don"t want to have to put anything above that in it.

[rickpilgrim]

If your planning on a head swap and your already at 9.1/1 you'll need an aluminum head which will let you run 91-93ron fuel at 10/1. If I were you I'd go right to Lunati 10120702LK cam swap and see how you like that before springing for a new set of performer vortecs (which are aluminum) as I know power is addictive but that cam may be what you need.

[Fitz]

Originally Posted by rickpilgrim

if your planning on a head swap and your already at 9.1/1 you'll need an aluminum head which will let you run 91-93ron fuel at 10/1. If i were you i'd go right to lunati 10120702lk cam swap and see how you like that before springing for a new set of performer vortecs (which are aluminum) as i know power is addictive but that cam may be what you need.

x2!