futurels1driver

Hey i just started tearing down the motor in my s10.its a 70's model 350 4-bolt(i think).right now it has a stock crank and rods with hyperutectic pistone(bored .030 i think)rock rpm air gap intake,a .490 lift cam, and a holloy 750cfm carb.What i was wanting to to is just get the crank ablanced,get it bored a little more(.040 or so or maybe just honed,get the mains line honed and make sure the assembly is good.but i definately want to keep the same rods and crank for cost reasons.I am going to go with a forged piston.now heres were i need the help.i am also wanting to keep iron heads for the cost and just for the hell of it.i dont know if i should get the vortecs worked or get some RHS,World,Dart,or Brodix(all irons of course).preobly wanting to have around 10.5:1 comp. ratio,dont know about an intake either.single plane of course.edlebrock victor series,dart,brodix,weiand..I am looking to get 420hp on motor with a 100 shot dry plate system through a built th350 or 400 and about a 3000rpm stall,9" rear with 3.73 gears with traction bars.Whats yall opinions or ideas?any are appreciated

1997bird

iTrader: (2)

Do you already have a set of vortec heads? Do you know the cam spec's for duration & LSA?

futurels1driver

yes i already have the vortec heads and i do not know anything about the cam except that the lift is .490.

1997bird

iTrader: (2)

I would keep your vortec heads and set the heads up for screw in studs, 2.00" intake valves, 1.6" exhaust valves, and port the heads. I would stay with the air gap manifold instead of a single plane manifold for your 150 HP and less n2o shot. I would also port match your intake to the heads. As for the piston's I would go 0.040" over with it and have a good machine shop torque plate hone the block. I personally like the Mahle piston kits for my engine builds. http://store.summitracing.com/partde...5&autoview=sku

futurels1driver

that is pretty much what i was thinking about the heads also.could you please explain in more detail why i should keep the air gap?wouldnt there be more power benefits with a single plane?its only goint to get drove on weekends.maybe 100-150 miles

1997bird

iTrader: (2)

You will make better low end TQ, but will lose very little on the top end. If you were going to shoot say a 175 shot or larger, the Victor Jr. would be a better distributing intake manifold. Here is a current magizine article for you to look at to help illustrate what I am talking about. This article is not yet on their web site, but if you go and look for the new Chevy Hi Performance (December 2007) on page 51-58 you can see some dyno results.

edcmat-l1

iTrader: (10)

DITTO. Single plane manifolds kill most SBCs. Unless its a radical stroker, capable of some pretty high rpms, 7000 plus, a single plane will hurt instead of help. ESP with a dinky .490 camshaft. That manifold would kill that motor.

futurels1driver

the .490 cam is not the one thats going to be in the motor when i get it back together,thats whats in it now.the cam i was probably going to go with was the Comp nitrous hp cam. 284/305 .507/.525.what about the carb?is the 750 holley(4150) gonna be enough or am i going to need to upgrade?

jmm98LS1

iTrader: (28)

The 750 carb will be gobs plenty for what you're building and will work just fine, but IMO it's too big. A 450fwhp 355ci sbc spinning 6500 rpm with 95% Volumetric Efficiency will only pull 634cfm. You'd need to spin it past 7500rpm before a 750cfm carb is necessary. A 650cfm carb will give you better throttle response and all the flow you need up top. Just my 2 cents though.

1997bird

iTrader: (2)

What goals do you have for how you want the motor to run? The reason I ask is b/c I am wondering why you would pick the biggest cam that Comp makes for the n2o. That cam is designed to be run with a multi stage n2o motor on more than a 225 shot for each stage. For just a 100 shot I wouldn't even be looking at any of their n2o cams. It would be lazy on motor where you would be at most of the time anyway. You might want to look at this cam instead http://www.cranecams.com/?show=brows...tType=camshaft .

futurels1driver

i would like to see 420-430 or more horse on motor and the 100 shot or so.it is only going to be used on the track and taken for an occasional saturday night cruise to a town close to me for some street action.i was not aware that the cam i had in mind would be too much since its not a whole lot bigger than whats in it now.i was thinking it would be fine since the vortecs could handle that much lift in ported trim.i am not that worried about street manners since like i said i wont be driving it alot.migh auctually haul it to the track since i have access to a diesel and trailer.i am by no means an engine building expert,hell im only 18,i know a little but need some help here and there and yall have been great help so far.thanks

1997bird

iTrader: (2)

I think that you would be happy with the results of the Crane cam that I provided earlier for you. It would work well with your 3000 stall converter and pull hard to 7k. Since you already have a 750 cfm carb right now I would first use it and tune it to the motor demands. You might have to drop back to a 650 cfm carb if it runs too rich for you. This combo would be street freindly and could be driven every day if you wanted to, so hauling it to the track is not a must.

futurels1driver

And another question.Anybody have any experience with the Speed Pro powerforged and durocoated pistons?amd alos their durocoated main and rod bearings?