Cam Selection

[Nymos]

I was wondering if anyone had any ideas for a good all around performance cam for a 68' 383. All i've found so far is RV cams, and it's not quite what i'm after. (mind you the motors going into a D-150 but i'm not going to be towing with it)
I'm running stock heads (2.08/1.74)
Edelbrock performer intake
750 Holley
Nymos

[This message has been edited by Nymos (edited January 05, 2001).]

[Streetwize]

The old MP street hemi with .474 lift and around 228 duration (284 advertised)@ .050 and 108LDA really wakes up a mild 383. Although this had decent bottom-end (considering its duration)Rhoads lifters makes a noticeable improvement down low. The newer replacement Street Hemi @ around 232 and 110 LDA, IMO, doesn't work as well in a 383 ( but better in a 440).

In a heavy car or truck, and assuming you have between 8.5-9:1Compression and dual exhausts ,I would look at either the Comp 270 (470" lift, 224@.050) or the Ultradyne 223/231. I havent run a Hughes smaller than a single pattern 230/230 (back when they were all single pattern), .515" lift , but they're 223-230 would probably work as well. I think I'd stay between 218 and 230 for a range and a 108-110 lobe center and you should do well. You might consider the Crane Variable duration (quiet) lifters to help enhance your bottom-end without needing to undercam (ex: 210-218 @ .050) the motor. Also, tight centers give you more lope and better mid range torque and acceleration where you'll need it the most in a truck.

Wize 1

[Streetwize]

The old MP street hemi with .474 lift and around 228 duration (284 advertised)@ .050 and 108LDA really wakes up a mild 383. Although this had decent bottom-end (considering its duration)Rhoads lifters makes a noticeable improvement down low. The newer replacement Street Hemi @ around 232 and 110 LDA, IMO, doesn't work as well in a 383 ( but better in a 440).

In a heavy car or truck, and assuming you have between 8.5-9:1Compression and dual exhausts ,I would look at either the Comp 270 (470" lift, 224@.050) or the Ultradyne 223/231. I havent run a Hughes smaller than a single pattern 230/230 (back when they were all single pattern), .515" lift , but they're 223-230 would probably work as well. I think I'd stay between 218 and 230 for a range and a 108-110 lobe center and you should do well. You might consider the Crane Variable duration (quiet) lifters to help enhance your bottom-end without needing to undercam (ex: 210-218 @ .050) the motor. Also, tight centers give you more lope and better mid range torque and acceleration where you'll need it the most in a truck.

Wize 1

[451Mopar]

I'll be the first to admit that I haven't had the best of luck getting my 383 to run like I wanted it to. In my case a 1971 383 with only 9:1 compression and a Crower #32242 Compu-pro cam with 271/284 advertised duration (222/234 @ 0.050"), 0.486"/0.496" lift, 112 LSA.
And mild ported heads with the stock sized valves.
This setup was weaker on low end power than I wanted, this may have been due to only having 9:1 compression, and I think that running more initial timming advance would have helped alot, but that would have ment re-curving the distrubitor to reduce the total amount of advance in the plate.
The engine did run pretty good from about 2,500 RPM to 6,000 RPM, but it din't make great upper end power either. I think this cam was too much of a compromise.

I'm not saying it was all bad, the car ran the 1/4 mile quicker than simular cars with near stock 440's. I think a higher stall converter would have made a big improvement also.

Anyhow, I think that for power, a cam with more overlap (narrower LSA) and maybe more intake duration would have helped the mid and upper range power, then use a 3,000 stall conveter and some more gear.

On the other hand, the stock HP cam with it's wide LSA is really a pretty good fit for a 383 that needs more low end torque, I just with the stock cam had more lift.
The Hughes HE1423BL would probbly work as a cam with better torque and extended RPM range. This cam has 214/223 duration @ 0.050", 0.470"/0.504" lift, 112 LSA.

[This message has been edited by 451Mopar (edited January 05, 2001).]

[Streetwize]

Yes, I think that a quicker advance curve might have helped, especially with the Crane adjustable Vacuum Advance kit. That particular Crower is Similar to the one I presently have in my 440 Charger (226/236@.050", .480/.506" lift) which runs 12.70's @ 110+ w/street tires, 3.54 gears and @ 3900 lbs. I believe that same grind on 108 centers would work somewhat better on a 383 unless the car was really light. Generally, I've found that Short stroke motors like 383's and 340's make better overall power with tight lobe centers, they tend to pull harder in the mid-range and only give a way a little low-end smoothness and maybe a little on the very top. The overlap can (generally, depends on a lot of other factors) give the intake charge a slight boost in flow velocity compared to a wider angle. This tends to be the reason that many 1/4-1/2 mile dirt track motors are in the 108-104LDA range.

112-114 LDAs tend to broaden/flatten the horsepower and torque curves and their smoothness can often be really deceptive in terms of how much power they really make. Some motors can make too much mid range torque and unload the chassis with excessive tire spin in that 3000-4000RPM gear change range; this is one example where wider lobes can actually help enhance acceleration. It really depends on the total combination.

Wize 1

[Warren J]

It's too bad that one of the best cam mfg, General Kenetics sold out. They had some of the best cams for stockers. Don McElroy, an old Mopar racer, would run more lift and duration on the exhaust. He had some of the quickest mopar stockers in the country. I also have a good friend that ran Pontiac stockers and the same, more lift and duration on the exhaust. About 10-15 degrees more duration on the exhaust. He seems to feel that 110-112 centerline for the street. Talk to the cam mfg and tell them what you are looking to do. Too much duration will kill low end more than likley the stock heads can't support it. It's nice to have a forum like this and have people that have tried different cams give feedback on what works and what doesn't.

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[66Dodge]

If my car has headers, full dual exhaust, and
super turbo mufflers should I be looking at the single pattern cams instead ?

[HOLESHOT]

ID GO WITH THE NEWER TECHNOLOGY OF THE COMP XTREME LIME AND STAY CONSERVATIVE AS THESE CAMSARE MORE AGREESIVE THAN THEY APPEAR.GENERALLY A SMALLER CAM WILL ALWAYS MAKE UP HAPPIER OVERALL.ID GO AROUND 214-218 INTAKE DURATION AT .050 GOOD LOW AND MID RANGE WITH SOLID 5500 TOP END

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[Morris Brown]

I agree with Holeshot. Comp cams have some Xtreme grinde that will wake up a 383. I would go with the K-kit. The 256-268 starts pulling at 1000 and quits at 5200. Strong torque through low end and mid range, good idle. The largest for a pickup that I would use would be the268-280 starts pulling at 1600 and goes to 6000. The 262-270 starts at 1300 to 5600. Any one of these cams will work well.

[Christopher]

I use the old Mopar street hemi cam in my 383 Road Runner and it works great.I've installd the newer version in other 383's and have had very good results.

[PRO]

In a heavier vehicle like a truck or full size car you dont want to sacrifice any bottom end in fact youd rather have too much,having run more 383s in my vehicles than anything else Id run the MP .450/,458 268/284,(P4452783)the extra lift and duration on the exhaust really helps as does the short duration on the intake side,youll love it,it turns on at 1800 and pulls to 5500......PRO....