Hi, I came across a deal I could not pass up on an engine block w/all the machine work done ready to assemble bored .030 over, stock crank, rods with new pistons and rings for $135.00, so I think its time to build a SBC 350 for my 1969 camaro. I want to keep this on a budget because this is a temporary motor until I can build a 383 stroker or BBC. I am shooting for around 425hp. II need some help with cam selection, transmission torque converter stall speed and anything else I can change to make this engine better.


Block: Chevy 350 bored .030 over, 2 bolt main w/studs
Pistons: Cheep speed pro hypereutectic Flat top pistons (Only using because they were free with block) H345NP30
Rings:?
Rods: GM Powdered metal 5.7”
Crankshaft: Scat 9000 Nodular iron crankshaft 3.48” stroke.
Heads: GM Vortec cast iron machined to except higher lift cam. 170cc intake runner, 64cc combustion chambers, 1.94/1.50 valves
Head Gasket:
Valve Springs: Comp cams 981-16
Rocker Arms: 1.52 Ratio, Comp cams magnum roller tip rocker arms 1412-16
Push rods: Comp cams 7812-16
Camshaft: Comp cams Hydraulic flat tappet XE268H /12-242-2, Dur. 268/280, lift .477”/.480 or the next step up XE274H/12-274-3, Dur. 274/286, lift .487”/.490” Will this cam still make enough vacuum comp cam guy said to use this one that the 268 is just basically an LT1 cam.
Carburetor: 650 Speed demon W/Vacuum secondary
Intake Manifold: Edelbrock RPM air gap 7516
Transmission: Turbo 350, Converter Stall speed?
Rear End Gear: 3.55? (Not 100% sure)

Looks like a good solid build.. not sure if youll make the 425 you want or not.. 425 at the fly or at the wheels?? Maybe at the fly, but it wouldnt at the rear.. Im not familiar with the cam, but the reast looks solid. Have you checked what your compression would run.?

425hp? no way!

do you have the cam yet?the xe274 is a great one and should get you over 400,also look at the lunati voodo series,230/236 in comp's measurements is on the edge for power accesories in a 350.
powerband starts about 2500 and really kicks arund 3000!
i think you'll be really happy with this one!
since you have a th/350 you can get a 3k converter for a great price(no overdrive).get the best one you can spring for! coan comes to mind,you want a converter that doesn't slip too much in normal driving or cruising,you get what you pay for here.
Eric B

425hp on the fly. I have two articals with engine build identical to this one and The one with the smaller cam made 408hp the other with the bigger came made 440hp. both with vortec heads. The block has not been decked so with the right head gasket I was told the compression should be right where it needs to be.

No, I dont have the cam yet, will the 274 still came make good vacuum for power brakes.

my setup was on the edge but i was way lower on compression(8.4).with flat top pistons you should be right about 10.3(assuming your vortecs are 64cc chambers)and that compression should bring you to right about 14" of vaccum,plenty for power brakes.
with the vortec's superior combustion chamber design,i would think you would be ok with 34-36*total timing which should still be ok with octane in the low 90's(maybe even 89)!
i started losing power brakes at about 11.7"vaccum but i think you'll be above that by a bit.
those heads maximize combustion efficency,and i think the combo (with the xe274 or a very similar cam)you are looking at will be picture perfect!
mine will be using the 274 with 9.5:1 and running on the cheap stuff!(with 30 or so more cubes)
build it!
Eric B

i have the 268 and have no problem with vac.. since you are on a budget like i am i should have known about htis sooner i just sold an air gap for vortecs brand new in box for 150.....i am running the summit stall. i know it was cheap but it works great for my daily driver and still gives me good launches at the track cant beat that for 100 bucks

check here for some awsome small street combos
www.ryanscarpage.50megs.com

Already tried combos take the guesswork out of it, I like to be the one finding the combo though.

You can also look at Professional Product Cross Wind intake. It is a knockoff of the Performer RPM Air-Gap for the Vortec heads for 129.00 out of Power House.

my 350 vortec/xe274 runs quite well... I'm gunning for the ever eluding 12.0's N/A this coming season.... XE274 is extremely streetable, pulls 14-15" of vacuum at a 800RPM idle. I couldnt be more happier with it.