260/300 rwhp/rwtq from a 5.0?!

[MadDAWG]

Valve spring would be huge. With that milage and running high rpms a new set is a given.

 

[25thmustang]

Our GT40P car with a stock cam, cobra intake, no porting, and bolt ons tossed down 288 rwhp. Thats stock 19 lb injectors, shorty headers, no AC or smog.

 

[91notch5.0]

jwzg. check out teambigblock.com for more pics of uh......our cars. you have good taste!

 

[57fairlane]

expensive valvetrain . . custom cam . . . ported heads.

go for it!

 

[northy_polk]

expensive valvetrain . . custom cam . . . ported heads.

go for it!

INexpensive is the key, as mentioned above...but yes it looks like a cam may be one of the allowable modifications. Probably not ported heads though.

 

[northy_polk]

Valve spring would be huge. With that milage and running high rpms a new set is a given.

As far as I know, IIRC, any OEM style valve springs can be used. Do you recommend any particular brand for this application?

 

[57fairlane]

INexpensive is the key, as mentioned above...but yes it looks like a cam may be one of the allowable modifications. Probably not ported heads though.

That is true but I wouldn't skimp on the valvetrain for a road race car.

Heck, find a chevrolet shop and see if you can't get some ls2 or ls7 take-off springs.
Those guys switch to giant cams (comparatively speaking) and I bought a set of ls2 springs (with 800 miles) for $20. They are currently on my ported e7s (getting the installed height right was a hassle however . . .)

 

[northy_polk]

Our GT40P car with a stock cam, cobra intake, no porting, and bolt ons tossed down 288 rwhp. Thats stock 19 lb injectors, shorty headers, no AC or smog.

Which bolt-ons? We can't run the P heads. How much do you think [realistically] the shorties netted you in RWHP/TQ?

 

[northy_polk]

Have the GT-40 heads and Cobra lower intake ported.

65mm TB, 24# injectors, delete the smog pump, a/c and p/s, cobre underdrive pullies, off-road exhaust after headers.

The camshaft is the x-factor. The cobra cam is not that good.

Hmm...why is the cobra cam [E303, yes?!] not that good? And which replacement, exactly, would you recommend?

Also, I forgot to mention after the stock exhaust manifolds, I'm running cat-less to an H-pipe then to Flowmaster 40 dumps.

 

[northy_polk]

i put down 270/298 with unported heads and intake. im still running the stock injectors for now. your numbers are low.

Hmmm....very curious as to EXACTLY what you're running. Is yours low mileage?

 

[MadDAWG]

The Cobra cam is not the e303. Some report actualy making more power with a stock ho cam in a Corbra motor. No idea if that is true or not.

As for springs I'd go with any of the major companies. I've used the Crane drop in set with good luck. I believe the TFS kit is simuliar, but a touch stronger.