Needs help.... Was wondering if it would be a good performance upgrade to put in a LT4 hot cam kit in my new 350/330hp gm hi perf crate engine. & if so i would need to get my heads reworked so they could accomidate a higher lift for the hot cam. if you think there is a eaiser way for me to get about 380-390 hp from my brand new gm hi performance 350/330hp crate enigine then plzs tell me ( here in a month i am going to put on a edelbrock rpm air-gap intake manifold..... then i plan on putting a 700 holley double pumper...... then after that is when i am going to put in my cam but i need to know what would be the best cam for my choice. the truck is mostly used as a daily driver but i want more power to kill off those damn import bugs.... the engine is in a 1971 chevy cheyenne long bed truck w/ a 3:73 gear rear & a th350 tranny.lso i live in AZ so i do have to passs emmisions but.... i will never be pulling somthing w/ it... it is basically my hot rod truck! any suggestions is well appreciated!!!

thank you for the time!!

Check out the Feb. 2004 issue of Car Craft , they just started a three part series ("Project humble pie") on a 330 hp crate motor. Theyre going for 400 hp too. In that issue they got 348 hp and 388 ft lbs w/ headers and a 650 cfm carb. Your heads will need to be reworked to accomidate the hot cams extra lift (.525 w/ 1.6 rockers). I would almost bet Car Craft will use the hot cam for their build too. Good Luck!!  

Hi 1320man,

I presume your 330HP / 380lb torque GM 350 has the Vortec Heads (Part # 12558060). Your problem with a cam exchange is that these heads only take a max cam lift of .475". Your cam is probably Part # 24502476, with max lift of 435/460. Doesn't leave much to play with.

All this info is on gmgoodwrench.com or Jegs.

If you read the General Motors claim carefully, they rate this motor @ 330HP when you fit some decent headers and a 650 holley. (I used a 750 V/S and had no real improvement.)

The Vortec heads can take a mild porting, and can be milled up to .040" for more compression (+ plus possible smog problems). The valve seats can also be machined to 2.02" intake and 1.6" exhaust. (From 1.94" / 1.50")

Plus 20%  power increase from this is a huge call, but you could at least talk to a mechanic you trust.

Playing with brand new heads,mannys and cams seems a terrible waste. You will blow of the little box on wheels in your current trim, and the next time you see him, he'll have his boost turned up, and you're dead man.

I'd shoot it with NOS, for another 75-150HP,  be cool with it and pick your targets! - cheap option, compared to big $ spend on what you currently have which is a great little street combo.

Cheers from your new mate in OZ,

Steve.

The new issue just came out and they hit 400hp with it.  

Hey homie have the same truck you do and the hot cam is not the way to go. It wont get through emissions with a carb. Fuel Injection will get it through with that cam, but that's about it. The cam in your 350H.O. has a lift of 460"intake and 490" exhaust right?Not too sure. Well unless the motor cam with 1.6 ratio rocker arms, that's what I'd do to get the specs of the hot cam near your cam specs. But I dought it'd pass emissions. If your motor cam with 1.5 rockers then the 1.6 rock with increase your  lift by.30". So that translates to a 490"intake and 520"exhaust lift. That exceeds the hot cam. If I were you I'd get the Performer RPM intake like you plan too and either a pocket port to the heads OR, a match port on the exhaust. Either or will increase power. Match port to the exhaust will increase torque, pocket port will increase a little of both. Hope this helps.