I know this place is for cars, but i really need help. I want to build a 383 tbi for my k1500. My plan is stock 193 heads with roller cam, headers, 1.6 rockers, and bigger TB. I was wondering what my torque and hp would be with this set up. I asked around on gmt400 and everyone tells me basically to build a 400hp 450 tq engine....i dont really need that much power, i would like 290 hp and 390 tq at the flywheel. P.s. roughly 9.3:1 CR the truck is going to be for towing and has the nv3500

 

anyone please?

 

How much power you get depends on how effective you are at tuning the thing when you're done building the engine.

No-one is going to be able to predict power without having been supplied with the "roller cam" specs.

The stock heads are going to kill power.

 

Thanks for posting this Schurkey. These two things (tuning, heads) are exactly what I was thinking, but I just don't have the hands on experience to want to get too far into the advice business yet.

But the heads are the key...OK for low end torque, they are a horsepower restriction on even a stock 305. Trying to feed a built 383 through those heads....seems like they'd be a REAL choke point.

 

trying to rbing this thread back to life because i for got about it but my cam specs 202 int./212 exh. .550 int./0.546 exh. again not out for a drag truck just a good pulling rig

 

Vortec heads and beehive spring kit on this engine with a good tune you will be glad you went with the vortecs instead of the swirlports. Ditch those 193s.

 

well guys my budget doesn't allow for a all out 383, however, i can afford a stout 350 build i was wondering what i would need for a 340 hp 380 torque while maintaining good bottom end for towing and 4x4 use my plan was
Vortec heads, roller 203/210 duration at 50 and 460 lift, 9.3-9.4:1 cr and a Fitech self tuning injection system, headers, free flowing exhaust, and roller rockers.

Any advice??

 

Don't get hung up on lift 'n' duration figures. Lobe centers and the resulting overlap are just as important.

The last couple of camshafts I bought were recommended to me by cam guru Harold Brookshire (RIP). Today I'd be asking Chris Straub or Mike Jones on www.speedtalk.com

Be sure to provide for appropriate "squish", no more than .045 clearance between piston top and the flat part of the cylinder head. This will probably require zero-decking the block, so that the piston comes up even with the head gasket surface. That way, the compressed head gasket thickness "is" the squish distance. .040 head gaskets are very common. Other thicknesses can be had, but the cost goes up.

Vortec heads are a good choice. Inexpensive castings, they do have some history of cracking. Check 'em before putting money into them. You'll have to have a Vortec-compatible intake manifold.

QUALITY roller rockers are nice, but not essential with the moderate lift 'n' duration you're talking about. Cheap roller rockers aren't worth the trouble. The Vortec heads are going to need self-aligning rockers.

Throw Vortec heads and an appropriate camshaft onto an early-90s B/C body 5.7L short-block, and you'd pretty-much be at your compression goals. The GM replacement engine was sold under p/n12513151, but that engine is now discontinued. I don't know if GM still sells the short-block (probably not.) I put that crate-engine into my '88 K1500. The cam is very mild, and it uses the swirl-port heads--but adds some compression and a roller cam (instead of the OEM flat-tappet) and runs flawlessly on the stock computer.