Thread: Feedback on this combo

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I was looking through this engine combo web site that was to me recommend i take a look at. and i ran across this one i would like some feedback on what you guys think of it. It was based on a 350 but i would do this to my 355 also i would chage the cam to the lunati 268 instead of the comp xtream energy. here are the specs any feedback would be appriciated. Also would a 2200 stall be suffeciant with this cam.

Displacement: 350 cu. in.
Carburetor: Holley 750 double-pumper
Heads: GM L31 Vortecs, pocket-ported, with 1.94/1.50 in. valves
Intake: Edelbrock Performer RPM Vortec
Camshaft: Comp Cams Xtreme Energy 268 hydraulic, with 0.478/0.480 in. of lift and 224/230° of duration @ 0.050 in. of lift.
Exhaust: Hedman 1 5/8 in. headers and Borla XR-1 mufflers
Distributor: HEI
Comp. Ratio: 9.4:1

MAX HP: 409 @ 6000
MAX Torque: 427 @ 3500

here is the link to the site http://ryanscarpage.50megs.com/combos13.html

Nice setup, but I wouldn't swap the cam. Extreme Energy cams is one of the hottest street cams there is available. Faster opening rates and more area. That would be sweet combo with a little more stroke like a 383.

I agree. Keep the Comp cam.

Originally posted by 1bad75vette
I was looking through this engine combo web site that was to me recommend i take a look at. and i ran across this one i would like some feedback on what you guys think of it. It was based on a 350 but i would do this to my 355 also i would chage the cam to the lunati 268 instead of the comp xtream energy. here are the specs any feedback would be appriciated. Also would a 2200 stall be suffeciant with this cam.

Displacement: 350 cu. in.
Carburetor: Holley 750 double-pumper
Heads: GM L31 Vortecs, pocket-ported, with 1.94/1.50 in. valves
Intake: Edelbrock Performer RPM Vortec
Camshaft: Comp Cams Xtreme Energy 268 hydraulic, with 0.478/0.480 in. of lift and 224/230° of duration @ 0.050 in. of lift.
Exhaust: Hedman 1 5/8 in. headers and Borla XR-1 mufflers
Distributor: HEI
Comp. Ratio: 9.4:1

MAX HP: 409 @ 6000
MAX Torque: 427 @ 3500

here is the link to the site http://ryanscarpage.50megs.com/combos13.html

I like it but I think the carb. is to big for your application.Try a 600 vac. or a 650 double pumper if you think you want a double pumper style carb.

I half-way agree with Erik on the carb. The dp has no place on a street engine, but a 600 vac has no place on a hi-perf street engine either. Go with a 750 vac. secondary with a rear metering block for full adjustability.

Originally posted by camaro_fever68
I half-way agree with Erik on the carb. The dp has no place on a street engine, but a 600 vac has no place on a hi-perf street engine either. Go with a 750 vac. secondary with a rear metering block for full adjustability.

I do like the idea of having the secondary metering plate for tuneability.If he goes with the 2200 stall speed the 750 might work very well.Even better on a 383.

Id use a Demon 625 personally

It's call a combination because someone tried different parts and dyno'd them until they found a combination of parts that worked best together. Any changes to the combination will result in less power.

maybe, maybe not, it is a combination, true, I could put a stock cam in a 350, with stock 2 barrel heads, 11.0:1 compression, a TeamG intake & a dominator carb & call it a combination. Sorry for the sarcasim) it is a combination, & it looks like a good one...I think with high velocity heads like those..a smaller carb would be a better choice with the given RPM range.

Also, it may have had had the best PEAK HP #s with the 750, but Id rather look at best overall #s if this is going to be a driver, rarly are you driving a street car @ 6000 RPMs

hi i'm new and was wondering why did some engines have less hp but more rpm?

Originally posted by camaro_fever68
I half-way agree with Erik on the carb. The dp has no place on a street engine, but a 600 vac has no place on a hi-perf street engine either. Go with a 750 vac. secondary with a rear metering block for full adjustability.

i dont wholly agree with the blanket statement of a DP not for the street...i do agree its over carbed but not WAAY over the top...

look into one of the edelbrock twin setups...even tho it has more cfm the edelbrock carbs are a vac of sorts carb and will only deliver what the engine needs...plus theyre easy to fool with and the whole setup is about a grand...

i definitely would chunk the HEI and get a good MSD pro billet and then use either a digital 6 or Mallory HyFire VI box and some MSD wires

you'll also find some piece of mind and performance by installing a set of Comp one-piece moly pushrods and some roller lifters

I agree with what techinspector1 said about the combo. If you're not going to use the combo as a package then build your own.

Careful using Edelbrock carbs on a vettte. The air cleaners will not fit under your hood. Unless you have a big block hood that is

@ speedvega:
maybe you want to start your own thread if you have a question that doesn't fit the thread you're posting it in. Not that many people care if a post doesn't match the thread, but you're going to get more answers if you start a new thread
But here's your answer: it's mathematical.
Power = Torque * RPM
That isn't quite correct because you need another factor to get your units correct, so let's call it
Power = Torque * RPM * X
and X is the factor you need to set your units straight, but forget about that for the time being, X is always the same and doesn't change no matter what engine you built. Think of it as something that doesn't need to bother you
So that means the following:
Engine A has a maximum of 300 footpounds of torque and delivers these at 4.000 RPM. Your power will be 1.200.000 * X Horsepower.
Engine B has a maximum of 300 ftlbs at 6000 RPM. Your power will now be 1.800.000 * X hp.
Engine C has 500 ftbls at 2000 RPM. That makes 1.000.000 * X hp.
You see? Torque figures can be lower on an engine that has more horsepower than on one with less power. A and B have the same peak torque but different power levels. Engine C has a lot more torque than engine A, but a lot less power.
The real question is: What RPM sees the Torque-maximum? The lower the RPM where max torque is developed the better the streetability is, but you won't get high top speeds. If you move the torque peak up the RPM-range power will be increased and you will get high top speeds, but the eninge won't be driveable under 3000 RPM maybe, so you can forget the engine for street use. That's why it's important to build your engine to fit the car and use it's intended to. Building a well behaved everyday driver which should be fast on the quarter mile strip is not really possible.
I hope I could help you,
Max