I am planning the build of a 350 heres the details. Completly new bottom end 10.2 compression, Cast iron Vortec fast burn heads, Performer RPM Air-Gap Vortec intake, Harland Sharp aluminum roller rockers, Hyd. Roller cam 280 duration .480 lift, and a holly 600 carb.

What kind of power do you think this new motor will make, and what RPM will i be able to turn?



Thanks,
Steve

 

Come on now, atleast give me some idea.

 

It should make 350-375hp.If the exhaust is up to par.I would
run a bigger carb though.

 

yea a 600 carb will limit your power to about 5,500 or so...

you should put out 350 horse easy and with a 700 carb itll make power to 6000-6,500.....but only if your motor can take it

 

I plan to build it with all high performance parts including Manly Light weight rods, and new speed pro pistons with a lightened cast crank. Because I realy want a high revving motor. Is a 700cfm or a 750 better to put? Any info you can give me to make 400 horses would be wonderful.

P.S. The car will have hedman long tubes and 2.5in duals it will also have a '92 Z-28 hood with functional ram-air vents.



Thank you very much for the responses

Steve

 

What's the cam duration at .050, the other number for duration does nothing for me? Assuming it's pretty decent it should make about 400 in really good tune. Most of the mag buildups do that after tuning/tweaking...

 

Havent seen duration at .50, I was just looking in Jegs and it lookd like a good one, but being its a roller, it should be pretty good as compared to a Hyd.

 

The closest I could find on Crane's website is a 278/280 roller 228/236 Duration @ .050, lobe seperation 112 with a .507/.525 lift.

Can the Vortec Fast-Burn heads support that much lift?


Thanks,
Steve

 

Not stock they wouldn't. You'd need to some work for the valve spring retainer to valve guide boss clearance issues, and you'd need different springs. You wouldn't want to go over .480 on the stock Vortecs, and that's pushing it (I would check the retainer to guide clearance before running it...)

If the duration on that other cam is 230+ plus at .050 that seems a little stout if you're planning to drive it around on the street much.

Of the mag buildups that hit 400hp or more, several were using the CompCams XE268 (224/230 @.050, lift of .477/.480), with the clearancing/springs done along with 1.6 rockers (so the lift would be like .507/.510ish)

 

Well, I was planning to find a machine shop locally to give them a 3 angle valve job and a little porting, so I'm sure the will be able to do that too. I was wandering about those sprngs didn't see to me they would do around 6500rpm.


Thanks so much for helping,
Steve

 

Yeah, shouldn't be a big deal then. I forgot to add, due to the not quite as stellar flow numbers on the exhaust side of the Vortecs, they seem to like dual pattern cams better than single. So I'd go with a proven decent pattern cam to help the exhaust out a bit instead of that original cam you mentioned...

I think advertised duration can vary from manufacturer to manufacturer, depending on at what point they measure it at. (why I think @ .050 is better anyway...) So that 280 cam may not be a large as I was thinking. But I think a dual pattern cam would be better anyway...

 

pretty much all of the rollers I see are dual patterns, the original one I posted about was actually a Crane Hyd. The one I will most likely get though is a Crane Powermax Hyd. Roller 284/292 duration with .509/.528 lift. So it will still need to be clearenced.

Another thing I was wandering was are these heads a good choice to make power? For $600 I would like to get some that will be somewhat matched with the mid-high powerband of my motor.

Thanks,
Steve