Need Cam advice - 383

Posted By: turbo36

Need Cam advice - 383 - 03/11/12 01:34 PM

I need a second opinion on some cam recomendations for my 65' Plymouth Belvedere II

Have two cam recommendations from Comp Cam:
XR274HR-10 //Duration: intake .274 - exhaust .282 // lift: intake .538 - exhaust .534 // lobe sep 110

XR280HR-10 //Duration: intake .280 - exhaust .288 // lift: intake .541 - exhaust .537 // lobe sep 110

Here is the build:
65' 383 Block, bored .060 over - deck cut .030 to correct a very bad previous machining job
516 Heads - cut to 71.25cc
low compression flat top pistons ( wanted to use forged stock height pistons but the top of the piston would be above the block height
comp ratio 9.5 to 1
1 3/4" headers
Eddy Performer intake
Eddy Performer 600 CFM Carb
Comp Hyd roller lifters
Comp Roller rockers
4 speed tranny
4.10 posi rear
MSD Ignition
tire diameter 26.2"
weight with driver 3,400 lbs

I want a quick/fun cruiser not a strip car.

thanks, Bob

Posted By: gch

Re: Need Cam advice - 383 - 03/11/12 02:06 PM

Go with the smaller one.

Posted By: lewtot184

Re: Need Cam advice - 383 - 03/11/12 02:32 PM

none of the above. when you use adjustable rockers with those cam profiles you will probably have piston to valve clearance issues and definitely retainer to guide issues. if those heads haven't had some serious reworking they can't use the extra lift. use an xe274 with stock stamped rockers and put the extra money someplace else. don't overcam!

Posted By: turbo36

Re: Need Cam advice - 383 - 03/11/12 03:07 PM

Why would adjustable rockers be different from non-adjustable?

The low comp pistons sit approx .080 further down the hole then the stock pistons, even with the deck cutting we are still better then stock.

Posted By: Dodgem

Re: Need Cam advice - 383 - 03/11/12 05:32 PM

I would go with this
XR280HR-10
especially with a 4 speed. and it will lower the cylinder pressures a bit so a little less chance of detonation!

Posted By: moparsquid

Re: Need Cam advice - 383 - 03/11/12 05:36 PM

with low comp id sugest a mp hemi grind or six pac grind,stock rockers will work fine and a 2800 stall converter and 3.91 gears.

Posted By: Mr.Yuck

Re: Need Cam advice - 383 - 03/11/12 05:45 PM

The smaller one and that is nowhere near enough carb.

Posted By: Black_Bee

Re: Need Cam advice - 383 - 03/11/12 06:36 PM

Do you already have the required lifters and rockers? Im sure that you are aware, but these roller cams you have been recommended cost a small fortune and seem really out of place in your build. If you have to buy the lifters and rockers to support the cam, you are looking at an something like $1000!

If you just want a fun quick cruiser, why not look at something like a Comp xe268h or even a xe274h for a fraction of the cost?

Posted By: lewtot184

Re: Need Cam advice - 383 - 03/11/12 06:45 PM

Quote:

Do you already have the required lifters and rockers? Im sure that you are aware, but these roller cams you have been recommended cost a small fortune and seem really out of place in your build. If you have to buy the lifters and rockers to support the cam, you are looking at an something like $1000!

If you just want a fun quick cruiser, why not look at something like a Comp xe268h or even a xe274h for a fraction of the cost?

good advice.

Posted By: turbo36

Re: Need Cam advice - 383 - 03/11/12 07:28 PM

Thanks to all the replies, very good advice. The reason I was leaning toward the roller lifters and rockers was to have a reliable cruiser using today's oils, cost wasn't a primary issue for this build.

Interesting thing; after reading these replies I went to the Comp Cam calculators to see projected HP and torque for these recommendations and was shocked to see the roller cams were 80-90 HP less then the flat lifter cams. Perhaps I'm missing something or the software is wrong??

I am reconsidering the XE series or the magnum (270H or 280H) series now and running the fortified race oils. I'll save my money for the 440 stroker build

Posted By: Black_Bee

Re: Need Cam advice - 383 - 03/11/12 07:45 PM

Quote:

Thanks to all the replies, very good advice. The reason I was leaning toward the roller lifters and rockers was to have a reliable cruiser using today's oils, cost wasn't a primary issue for this build.

Interesting thing; after reading these replies I went to the Comp Cam calculators to see projected HP and torque for these recommendations and was shocked to see the roller cams were 80-90 HP less then the flat lifter cams. Perhaps I'm missing something or the software is wrong??

I am reconsidering the XE series or the magnum (270H or 280H) series now and running the fortified race oils. I'll save my money for the 440 stroker build

Regular oil plus a ZDDP additive is pretty cheap.

Something isn't right with Comp's calculator then... from a stock cam to the largest solid roller and everything in between, it is unlikely that there would be 90HP difference in your combo coming from the cam only.

Posted By: MoJoe

Re: Need Cam advice - 383 - 03/11/12 09:10 PM

I have the xe268h in my Roadrunner without the roller set up. I have basically a stock rebuild .30 over, stock exhaust manifolds, 355 gears, 4 speed, DP4B intake and the 600 Eddie carb. It's fast and fun... I like it.

Posted By: Junky

Re: Need Cam advice - 383 - 03/11/12 11:26 PM

If ya want a fun cam for the street, try the Hughes Whiplash cam. I have that in my 383. I'm very happy with it.

That 600 carb ain't gonna cut it! A good carburetor, among a few, is the Holley 750. Good all around carb for what you need and the one I run.

Posted By: lewtot184

Re: Need Cam advice - 383 - 03/12/12 01:17 AM

Quote:

Thanks to all the replies, very good advice. The reason I was leaning toward the roller lifters and rockers was to have a reliable cruiser using today's oils, cost wasn't a primary issue for this build.

Interesting thing; after reading these replies I went to the Comp Cam calculators to see projected HP and torque for these recommendations and was shocked to see the roller cams were 80-90 HP less then the flat lifter cams. Perhaps I'm missing something or the software is wrong??

I am reconsidering the XE series or the magnum (270H or 280H) series now and running the fortified race oils. I'll save my money for the 440 stroker build

you can buy an awful lot of zinc additive for the extra cost of a hydraulic roller, not to mention that to my knowledge nobody makes a good .904 hydraulic roller tappet. i was just over at the 62-65 mopar site and there's a good article written by don dulmage on building a 383. read it and take special note about cam profiles, piston to valve clearance. they're good engines, i used to hot rod them, but easy to screw up with hot cams.

Posted By: dogdays

Re: Need Cam advice - 383 - 03/12/12 03:13 AM

I agree. All of the cams are too big except maybe for the 268, and I'd go a step smaller than that!
A 383 is ridiculously easy to overcam.
Those hydraulic rollers are way too big.
IF cost is no obstacle I'd say telephone Hughes and talk it through. Buy the whole shebang from them and you should be good. Most of the cam manufacturers are 10 times more familiar with a chevy engine than a Mopar, and a smallblock chevy 383 is a whole different breed than long-rod short-stroke 383.
Or go to the Lunati Voodoo series, probably a 302.

R.

Posted By: Dean_Kuzluzski

Re: Need Cam advice - 383 - 03/12/12 09:08 AM

Just my opinion but if you're going to run a 4.10 gear and a 26" tire......

then I'd add more cam, carb and intake to make it worth all that wasted rpm on the street.

Or, dial back to a 3.55 to use the low-end torque the milder cam/intake/smallish carb will provide for you.

Add the 1.74 exhaust valve to those 516's, if you haven't already, do a bowl porting to clean them up. Run the thin steel headgaskets to get best compression.

Personally, I'd run a Performer Rpm or an old DP4B, a 700 cfm Holley and a cam with 224-228 @ .050 duration. Once you get into the 230+ duration cams, carb & mech. advance mods, although already required, get pretty intense for best throttle response/driveability.

Your set-up with 3.55 gears would be good spirited driving with some very respectable fuel economy.

Posted By: 340SHORTY

Re: Need Cam advice - 383 - 03/12/12 02:15 PM

I personally wouldnt run either 1 of those cams.
I hope you put larger valves in those 516s. I tried a set and my 383 quit pulling arount the 1000ft mark in the quarter. put a set of 452s and they made a ton of difference..

Posted By: CompSyn

Re: Need Cam advice - 383 - 03/12/12 07:30 PM

Give Bob a call...