New cam for the 383

[Paul G]

I tore down the 68 383. Getting new rings and bearings. The cylinders have a little taper but not bad.

Re using the pistons, L2315 .030 over. They sit .020 in the holes. On Summits site the compression ratio calculator puts it at 9.1:1. How accurate?

The 906 heads on the engine were not good. Sinking valves, worn guides, etc. I cleaned up a set of 452's. Gasket matched and some light clean up inside the ports, lapped the valves, they look good. The 452's had stock, light springs. Swapped out the stiffer springs from the old 906's to the 452 heads.

The old cam has a lobe going flat. Crane HMV 278, 222/234 @50, 467/494 lift, 114 LSA. It is a 1 bolt, and I just replaced the timing set, 1 bolt.  

I found a Crower 271HDP 1 bolt, 222/234 @50, .486/.496 lift, 112 LSA. similar to the old crane. Is this a good choice for a hot street engine? Anything better?

I have a Comp XE256H-10, 212/218 @50, .447/.455, 110 LSA. It is small cam. How would it perform in the 383?

[AKcharger]

I think Good!!

[BSB67]

All three are fine IMO.

I like the Crower the best.

The Comp would be the snappiest down low.

[Paul G]

I like the Crower too. Just worried it might be too much after reading Crowers spec below. The rear gear is a 3.91, tire diameter is 28", which fits Crowers recommendation. Even the converter is a 2500 stahl lock up converter. The car cruises at 70 MPH in overdrive and lock up just under 2500 RPM. 

Recommended Modifications   

These higher lift and longer duration camshafts demand close attention to rear end gearing and tire diameter combinations. The secret here is to pick a ring and pinion gear set and tire diameter that keeps the engine in its optimum rpm power range. Automatic transmissions with an aftermarket high stall torque converter and manual transmissions. Headers, dual exhaust, larger than stack carburetor, performance manifold and increased compression (9.5:1 to 10.5:1) are required. Mild porting and larger valves will improve performance.

[Paul G]

And here is a real cheapo cam. Summit house brand. Only $79.99

Duration at 050 inch Lift:       224 int./234 exh.
Valve Lift with Factory Rocker Arm Ratio:   0.466 int./0.488 exh.
LSA 114

[Nacho-RT74]

I'm running 282HDP Crower on my 400 with 175K MP TC ( supossely 2400-2600 stall ) and 3.55 gears on SG... but is true is a stroked 400 ( 3.75 ) with around 10:1 CR and I like it. I think sooner or later will go with a better TC thought but my car is/will still be a driver.

Is for the 4s peeds Rallye Charger ? I think you'll be fine with the Crower 271 being manual.

( not an expert LOL, but just a theorical reader LOL )

[Paul G]

How much vacuum can I expect with the Crower cam? Spec, 222/234 @50, .486/.496 lift, 112 LSA
I was getting 16" with the old Crane cam. Spec, 222/234 @50, 467/494 lift, 114 LSA

The crower has a tighter LSA. Will that effect on vacuum? Or using EFI?

The car has power brakes. Using long tube headers, 2 1/2" exhaust, Eddy duel plane intake. With EFI in the future.

[bee1971]

Those Speed Pro 2315 pistons are flat tops - Mine where .024 in the hole - I ran them for 20 years within my matching 383 with a Mopar 284 - 484 Camshaft with zero issues

As soon as I went to aluminum heads one summer a few years back with bigger valves the motor lasted one week

Two intake valves kissed those same pistons running that same Camshaft

Watch your Camshaft duration and lift along with head valve size on whatever package you put together

Peace

[Paul G]

I called Crower this morning to get there expert opinion on the right cam to use. Talked to BJ, he chose a much smaller cam yet. #32916, grind #265H, 218/222 @ 50, 475/484 lift, 112 LSA.

[Nacho-RT74]

being .020 down the hole and depending on heads volume and gasket thickness... it could be for an auto car ?, but being manual I don't think the 271 is really huge for it. You can allways get a metalic headgasket and a light mill down job to the heads too.

Once again, just a theorical opinion

[Paul G]

This is going in the 72 overdrive automatic car.

[Nacho-RT74]

Oh! Ok diff deal then! The lower step Crower Seems to be way better option than the Comp, Althought I still likes the 271 for it.