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Discussion Starter · #1 ·
i have lingured here often over the years..
i just swapped out a tired no compression 2 cylinders 283 for a 350
hello fellow Rodders,
i just accuired and swapped my old 283 for a rebuilt 350.
the new engine is a stock bore stock stroke 2 bolt main 350.
i am curious as to a ball park HP torqure.
here are some specs.
882 heads 2.02 valves bronze guides
roller rockers
roller timing chain
.275 dome pistions (estimated CR ratio 9.3:1)
summit k 1104 cam 224 intake 224 exhaust duration. .466/.466 lift. 114 seperation.
"new" hooker cast 2.5" manifolds true duals (no x no h) 2.5 to axle 2.25 from there back
it is in a 51 GMC cruiser, M2,coil rear, 3.42 gears
please give me an estimated HP and TQ
i am aware the 882 heads are "not good_ not interested in tearing into it. just want to know what i have.
THANKS in advance.
Marty
 

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HP guess questions are placed here in Basics forum , where i moved your thread to. I deleted your 2nd thread on the same question.
 

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Except for heads this is a pretty decent street performance build. You restored compression, increased valve size which as much as anything with these heads is useful if they came with the typical two piece welded head to stem valve that occupies a lot of valve pocket space with steel, so if your increased diameter valves are the more streamlined modern version that is much slimmer on the back side of the head this alone substantially improved breathing without porting. No question that with your setup the use of a modern head would net 40 to 60 more ft pounds and horses, but unless you landed a pair of modern chamber heads with 72-76 cc chambers the pistons would need to be changed out.

The ratio of the roller rockers count the torque and power numbers I’ll suggest are for a 1.5 standard Chevy 1.5:1 ratio the use of a 1.6 ratio would add from 10 to 15 units of torque and horsepower.

Manifolds over long tube headers are delinquent about 8% on torque and 7% on horsepower.

A split duration cam with more exhaust duration than intake is helpful on street engines as it compensates for the back pressure caused by a full exhaust system. These straight timed cams are better suited to engines running open exhaust at the header collector. For the street this is more a nit than a negative.

I’d call this at 370 to 380 ft pounds at 3600 to 3800 RPM for torque and 290 to 315 hp at 5500 to 5800 RPM at the crankshaft on a crank dyno with open manifolds and turning the water pump.

Bogie
 
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