vortec heads cam??

[chillywilly]

Just picked up a core vortec 350. /forums/images/graemlins/grin.gif.Gonna put the vortec heads on my older short block with flatops.Anyone using this setup and what cam did you use, Im thinkin comp xe 268 or bigger.Dont need streetability,going in my mud truck want most power at 5500 to 6000 rpms. Guy I work with is gonna do the machine work for better springs for cheap.I have all the rockers and valve covers.Just have to buy intake.xe268 is a little pricey for this season,anyone know of a cam with same perf cheap? Next year Ill be redoing the roller block, maybe 383? /forums/images/graemlins/shocked.gif lol /forums/images/graemlins/truck.gif

 

[ben427]

Just a heads up, the 64cc vortec heads and flattops will prolly bump your compresson way to high for pump gas.

 

[chillywilly]

Thanks for the advice,Im prepared to use race fuel. kinda a single purpose truck on and off trailer and into mudpit /forums/images/graemlins/grin.gif gotta luv it /forums/images/graemlins/thumb.gif

 

[dyeager535]

I know you already have the heads, but double check what kind of numbers they turn out at those kind of RPM's. I know they flow real well, but not sure how they compare to other heads up high.

As well, the 1.94 valves are a little bit of a hindrance when you start talking about high end power. This of course is if you are talking about competing, if it's just for fun, disregard.

I've got "flat tops" in the 355 I'm building (speed pro hypereutectics) and the compression with 64CC heads, and a "standard" thickness head gasket is 9.2:1 Even carbed with the Vortec heads you *should* be able to run that with 87 octane. Not that it concerns you obviously, just a FWIW.

 

[chillywilly]

Thanks for the reply. What cam and how will you be using your engine? Ive done a lot of research on the vortecs and they seem to flow great to at least 6000rpm.Larger valves can actually hurt perf with this chamber design.Chevy hi performance just did a series on these head with stock bottom and made 420 hp.

 

[dyeager535]

Car Craft has an article in the July '03 issue, that is about porting the Vortec heads.

Gains after porting start to be really noticed around 4400RPM, with an additional 16.9ft lbs of tq at that RPM, and + 17hp at 4500RPM. (max tq/hp seen with porting: 37.4/46)

Torque PEAK before porting was 464.4@4400, HP peak was 436@5500. After porting the peaks were 481.3@4400/464@5700.

Sooo...there are some gains to be had when working with these heads, especially on the upper end.

Motor specs: 10:1, .060 over, Total Seal Gapless rings, Lunati 230/[email protected], Performer RPM Air Gap, Demon 750, .039" head gasket.

My cam is a 204/214 Crane grind, the one that appears to be the most effective for low end torque. It's a roller cam/roller rocker setup, .030 over, TPI, with Vortec heads of course.

I really should have gone with different heads, the lack of inexpensive intakes for TBI/TPI with Vortec heads is unfortunate. Vortecs are also supposed to be prone to cracking (quite thin castings) but I'm sure thats mainly just a problem in racing applications.

I mean if you can eliminate the acquisition cost and machine work cost of the Vortecs, they are a great deal, but I have a feeling something along the lines of AFR and the like have heads that will perform better at the higher RPM's most racers turn. Great heads, but there are better out there, all things considered.