I'm going to start building my 383 stroker and i need to decide on a cam. I want a nice rumble/choppy idle. Stall converters arent an issue at this point because i'm converting the car from a 5 speed to a TH400. when it comes time to build the trans i will buy the appropriate converter for the set up. From what i've been reading, the cam cannot be too big because of clearance issues with the connecting rods. Having the rods machined is not an option at this point because the rotating assembly is already ballanced and i dont want to get it done again. I'd like to get the biggest cam possible but i dont want to cause any clearance issues. does anyone have a suggestion or 2 on what cam i should go with?

 

Here are the specs for the Dart heads that i have also. I'm sure this would help with picking the correct cam thanks again.

Combustion Chamber Volume (cc) 64
CNC-Machined Combustion Chamber No
Intake Runner Volume (cc) 230cc
Exhaust Runner Volume (cc) 75cc
CNC-Machined Intake Runner No
CNC-Machined Exhaust Runner No
Combustion Chamber Style Heart
Intake Port Location Standard
Exhaust Port Shape Square
Exhaust Port Location Standard
Spark Plug Style Angle
Intake Valves Included Yes
Intake Valve Diameter (in) 2.080 in.
Exhaust Valves Included Yes
Exhaust Valve Diameter (in) 1.600 in.
Valve Springs Included Yes
Maximum Valve Lift (in) 0.690 in.
Outside Diameter of Outer Spring (in) 1.550 in.
Damper Spring Included Yes
Number of Springs Per Valve Dual
Retainers Included Yes
Retainer Material Steel
Locks Included Yes
Lock Style 10 degree
Valve Stem Seals Included Yes
Valve Stem Seal Style PC seal
Rocker Arm Studs Included Yes
Rocker Arm Nut Thread Size 3/8-24 in.
Rocker Arms Included No
Rocker Arm Nuts Included No
Guideplates Included Yes
Guideplate Pushrod Size 5/16 in.
Valve Cover Mounting Style Center and perimeter bolt
Accessory Bolt Holes Drilled Yes
Valve Guides Included Yes
Valve Guide Material Manganese bronze intake/Phosphorous bronze exhaust

 

Get a small base circle cam if you are so concerned with it hitting the rods. Also higher ratio rockers will help yeild more lift from a smaller lobe.
I am running a solid roller on a small base circle that yeilds just over .600" lift but i am sure i can go much bigger.

 

Those are some big heads. Aluminum or Iron? Your gonna need to turn some rpm to get some use out of them on a 383. What intake setup are you running?

Also what rotating assembly? Small base circle can provide big lift and large duration with no rod interference

 

i'm not sure on the intake yet but its definitly going to be enough to accommodate the heads.... for the carb i'm probably going to go with a holley 750. The rotating assembly that i purchased is from eagle. Part # B13405E030. flat top pistons with 2 valve reliefs. The heads are iron. when i found out they were only 500 bucks a piece i had to get them haha

 

Based on that rotating assembly, i would spin to high - cast crank and long stroke. But those head will flow a ton. I might recommend a solid roller. looking like the valve springs are pretty hefty. also, if you plan on taking advantage of high lift, get 7/16 studs and/or a stud girdle. i learned the hard way with big lift and 3/8 studs.

rough estimate - about 10.7:1 cr. what is your deck height? headgasket?

comp cams solid roller - xtreme energy, most area under the curve. XR280R, 242/248 @.050, 2500-6500, .57/.576 lift w/1.5. recommends 2800 stall.

also, with those heads, you could probably do a holley 850.

just what i'd do.

 

Go custom cam.....hit up Lloyd Elliot or Advanced Induction. Tell them everything you know about your car, and tell them what your goal is. They will hook you right up. Can't go wrong with custom cam.

 

Being Iron heads, you'll want to keep compression down to about 10 to 1 and no more.

They are setup for solid roller so you should look into one. I second the 242/248 cam or something similar in that duration range. Very nice street/strip solid roller for a 383 inch motor.

 

Ok i did some research on the XR280r cam and it seems the duration jegs lists for it is a bit more. heres the link to their page


http://www.jegs.com/i/Comp-Cams/249/...ductId=754879#

the deck surface has been machined .010 and as for the head gaskets.....im going to go with the felpro HP's (part #1142) which are .041 .

 

its 280/286 advertised but 242/248 at .050 which is most common way to express cams

 

looks like you are at 10.68:1 cr. what elevation are you at? the cam has an intake valve closing point of 66* abdc. you could run that CR with premium and good carb tuning. check to see what your cranking compression is. 180-200psi is about the max for pump gas. otherwise... cnc the chamber to get a few more cc's and lower the CR... but thats $$$.

 

how about some slightly thicker head gaskets?? as far as elevation, it varies quite a bit up here. anywhere from 500 feet to 2500. living in the pocono region kind of sucks haha.

 

Ok I went out and picked up that cam for 220 bucks. As far as redcucing the compresion ratio... Does anyone have any ideas?

 

pick different heads with larger chambers or go aluminum, or change pistons out, or just run E85/higher octane fuels, maybe some meth injection

 

alright maybe i'll try to go with the 72 cc heads.........i gotta see if i can get them through where i work... is it possible to run on 93 octane with the setup i currently have? i dont have a problem with that. i'm not going to be driving the car everyday so its not going to kill me. even 97 octane would be fine...

 

based on my experience, using 93 or 97 octane would be fine with 10.7:1. just make sure you timing is good, keep your motor cool (170-190), and make sure to not run to lean. with 72cc heads, you cr might be to low for that cam. then you would need to mill the heads, change the cam, and loose power.

 

Well that works for me. I have no problems with running higher octane fuel. Now If I had to run cam2 all the time I would consider making changes to my setup. But 93 and 97 ocane are fine for me.

 

okay just a quick confirmation here. the XR280r cam will clear the connecting rods in the 383 stroker correct? i dont want to install this thing and have it not work. i'm not sure if i would be able to return it if i had it installed in the block. thanks.

 

I want to say I beams have more clearance than the H beams and that the cam will clear but I dont want to give 100% confirmation. I ran a big lift, decent duration cam in my 383 with H beams and that cam was on small base circle but had good clearance. I think a regular lobe cam would have cleared.

I think the type of rod bolt also has an effect on the clearance. Rod bolts are better than cap screws i think

 

i have the rod bolts with my set up. no cap screws for me. i spent the better part of today grinding away at the block to give the rod bolts some clearance just under the cylinders. I already have the bottom end completely assembled except for the cam. as of now i really don't want to install it unless someone gives me some more feed back on the clearance issues. If grinding the rods down to make more room were a possibility, then i wouldnt care but since everything is already balanced and assembled, i'd like to keep it that way :-P

thank you orr89rocz for all of your help on this issue. i appreciate it.

 

you dont have a stock cam laying around do you?

Else just order one on a small base circle from comp, i dont think its extra money. I believe their custom grinds are same price as off the shelf now

 

no i don't have a stock cam..... the one that i have i got a pretty good deal on (about 50 bucks less than summit racing) I'm going to E-mail comp cams and see if they have any info on clearances for the 383 stroker.

 

When i bought mine there was a charge for custom grind. But it wasn't much, maybe 15 bucks or something. That was a little over a year ago.

 

okay i just got the nudge that i needed to install this cam tomorrow. comp cams has a program on their website called camquest..... you put in the specs of the engine and what not and it gives you a list of cams that will work with that and how it fits. i did that and the cam i purchased came up under the GREAT FIT category haha. now if for some reason i do have a problem tomorrow, i can blame comp cams for the screw up. not myself :-D thanks for everyone's help on this!!:-D