Would it be possible to make around 375hp at the crank with a carbed vortec 350 and the right combinationof parts? Basically, would a Vortec 350 be a good base to start a carb build up?

 

CarCraft did it last winter with the GM Performance Parts 350 HO. Look for some back issues. They went from the base engine with hydraulic flat tappet, edelbrock rpm and 650(?) holley to more radical mechanical roller cam. Maxed out at over 400hp.

 

Seems like nothing out of the ordinary, I'll bet it can be done. Make sure to post pix of your setup process

>lol I wanna see how far I can take my 305 with vortech heads, mild cam, and my holly 650. Just slip the cam in, bolt the heads and new intake maniofold on. hmm... if I didnt pay my bills... I could do this now! lol

 

It's been done several times. I have done it, along with countless others. To acheive 375 at the crank, basically you could run them factory, un-ported. However, I would take them in and have them machined for a few things. First, have them mill down the guide boss to allow for more lift (that increases the distance between the bottom of the retainer and the top of the guide boss). From the factory, Vortec heads max out at about .480" of lift, quite possibly less. Second, have them machine for screw in studs. Vortecs have the factory pull out designs which faulter at anything above factory spring pressures and/or .480" valve lift. Any decent aftermarket springs would have enough spring rate to offer enough resistance to yank them. The third thing would be opening up the spring seat for a larger diameter spring. Depending on what you plan on doing, this may or may not be completely needed. There are several springs thta do fit in the factory 1.26" OD spring pocket. Comp 981 springs come to mind as do the Isky 235-D springs. The 235's have a slighty larger spring pressure, probablu better suited for a roller, however, I am using them with a Lunati flat tappet cam. Both work fine.

You'd obviously have to get a specail Vortec intake. The best choice would probably be the RPM series, either the air gap or non, depending on what you prefer. That, paired with an Xe274h Xtreme Energy flat tappet cam by Comp Cams would do fine. I'd aim for like 9.5:1 compresion and you should be there.

My setup will be as follows:

Vortec heads (906 castings), ported and polished
Lunati 00010 flat tappet cam (230/230° @ .050", .480/.480" w. 1.5 ratio, 109 LSA)
Around 9.5:1 compression ratio
Edel. Rpm intake

 

http://www.carcraft.com/techarticles/81998/index.html

http://www.chevyhiperformance.com/ho...458/index.html


Hodge

 

i'v built a few of em and help friends build a few of em. all or em that ar running are in the 12's or in the very low 13's and getting closer.

i'd do it this way.
heads.. get a valve job on the heads. cut the seats. for the springs.. it's inexpensive. get "z28 springs" 1.5 roller rockers, deck the heads if they need it, no need to "port or polish"

go with a performer rpm or the rpm airgap intake.. 1" spacer. 750 vs holley if it's mainly street or a mech one if it's mainly strip

Hei distributor, pertronix flamethrower rebuild kit
r43lts plugs... two lightest secondary springs. total advance 36* by 3000rpm

if you've got the coin for a 4130 forged crank (eagle has them for appox 400 bucks) i'd get one.

stock volume pump with a white spring, windage tray. there's NO point int putting a HV pump in there with a stock pan, on a motor that's going to spin up over 6k. it'll suck it dry.... or so is my paranioa... but irregardless. it is unneccesary.

Zero deck the block align bore it.. punch it .30 over
Forged Trw flattops with the 4 vavle reliefs... X rods. ballance the assembly .039 head gaskets.

with those goodies your looking at 10.-10.25 compression. afriend with this setup even runs his on midgrade gas from time to time.. don't be afraid of the compression

I'd go with an XE268 cam if under 400 is your goal.. you'll get it easily will be very driveable. personal pref is a th350, and a 3000stall converter with 3.73 gears with "stock hieght" or slightly taller tires.

that'll get your the 375hp and get it to the road reliably.. even at a road driven thirdgen wieght of 3600lbs.. it'll get you mid to high 12's

 

I completely agree with Pony Killer on every single aspect. However, I'd say if you wanna ensure best 1/4 mile times over best street manors take that combo he listed and get a little more converter and gear.

I have yet to run my car at the track (one problem after another but I'm running out of things to replace... "if it can break, it will break") but I'm sure it'd also have no problem running mid 12's in my heavy car. I've been considering swapping my current "too big" cam out for the XE274 just to see what happens, who knows... I just figured I'd try smething different and see what happens.