What cam to use

[tscott9330]

Ok, I need to get a cam for my new engine. It is going a 383 stroker. All i have is the stroker kit installed from powerhouse and I think i'm gonna use their cylender heads, the ones with the 76 cc heads and i'm not sure of the intake yet.. What cam do you all think I should run. I'm shooting for around 400 horse power.


Tom Scott

 

[82mystery]

cam 400 hp

hello tom, i assume you building a hot dailey driver. cams and heads work together a lot and if it were me, i would contact your favorite mfg. and tell what them you have , such as car weight and intended use ect., i personelly like crane or competition cams.i would just call or e-mail them and wait a few hours for the results. for a dailey driver i really like a hydraulic roller with about 228 degrees duration and 112c/l with about 510 inch lift. gm performance has one that costs about 500 or so with lifters and roller rockers. a flat tappett would be 25% cheaper than that. again i would strongley suggest that you get with the cam mfg because you are the one that has to live with it . i hope this help you out and good luck with your build..have a great day. you might want to go with a duel pattern cam also .if this a earlier blk.before 86 i think, you would also need retro fit roller lifters. larry

 

[AKRAY4PLAY]

how much do you want to throw at it?? what rpm range do you want?? are you going to be upgrading in the future?? how much torque do you want?? there are several cam/head options you could go to reach your power goals. i would suggest that you go with a good aluminum head and a milder cam. this will keep idle smoother and tuning easier. a radical cam and iron heads will be cheaper, but tuning and later improvements will be harder. check out Fred's (FC3) engine build. he has a nice 383 with AFR 195 heads and i think a crane 268 cam. search under 383 retro in the archives, he posted the build from start to finish along with some very nice photos. if you go with iron heads, 76cc is fine. aluminum heads i would suggest you run 68cc chambers. Brian

 

[Jack]

Since this is a 383 ... you need to determine if there is potential of cam-clearance issues ... i.e. will any of the tops of connecting rod bolts come within about 0.050" of contacting any of the cam's lobes? If there's an issue ... you may need to get a small base circle cam ... or limit yourself to one with less lift/duration/advance.

What kind of rods do you have? ... 400 (5.565") , 350 (5.7") aftermarket (5.7", 6.0" etc)?

Have the rod tops/bolts been "cam-clearanced" ... or are they designed with a profile for stroker clearance?
JACK:gap

 

[tscott9330]

Here is the details on the stroker kit got:
Chev. 383 Stroker Kit 5.7 Rod Flat Top Piston (2pc seal/carb) 1pc seal optional
Powerhouse 383 Stroker (5.7 Rod) Piston; 10.7 compression (using 64ccheads)
9.5 compression (using 76cc heads)Street/Strip rings; CR1 5.7 rods
rod bearings; main bearings; complete gasket set (2pc. seal/carb)
Includes brand new 383 Stroker cast crank only $469


As for the rpm range. It will be a daily driver, and i'm sure it will see the strip a time or two if you know what i mean.So I figure 1000-5500 or somewhere in that area. I was planning on cast iron heads to save on cash. And because I want the vacuum system to work I was going to go with a mild to midrange cam.
My gola is around 400 hp and 400 ft/lbs but i want it to drive well.

I also plan to put on edelbrocks pro flo efi system which i hope will make it very streetable.

Tom "tell me what ya think" Scott

 

[Jack]

TS:
So far ... kit is for 5.7" rods.

Still ... no indication if rods you are using either have been cam-clearanced or have adequate profile ... for use with standard base circle cam.

Below is link to pic of GM 5.7" rods I clearanced for 383 ... top rod is a virgin ... bottom rod is cam-clearanced at top of rod/bolt ... if you can't link to it lemme know & I'll email it.
http://www.imagestation.com/picture/sraid20/p95fb733a02251f858d80be84b61b2390/fdbd8628.jpg.orig.jpg

Is an experienced builder assembling motor?
JACK:gap

 

[tscott9330]

I cant link to the pic. If you would email me i would appreciate it.

send to tscott9330@aol.com

The top of the rods dont have any protruding edged so I assume they have been clearenced because if they have not been there isn't much more you could take off with out weakening the part to much.

Tom Scott

And yes a good builde is putting the lower end together. I was gonna do it but figured since it is gonna be a daily driver that i would do everything i could do to make it reliable.

 

[Jack]

TS:
you have mail w/pics attached. Your builder should ensure clearance is ok ... if he is installing cam.

For what you're after, roller setup not needed. A hydraulic flat tappet setup will be just fine ... and many bucks less. Use valve spings & rockers appropriate for cam. I'd call comp, crane etc with your trans type & rear gear ratio.
JACK:gap

 

[tscott9330]

ok, So lets assume the rods havent been clearenced. What cam should I run. Keep in mind i'm going for around 400 hp and 400ft/lbs on pump gas, and because its pump gas I am shooting for just under 10:1 compression ratio. and i will be driving this car alot.


and now lets assume That the rods have been or can still be clearenced for the cam.

What cam should i get for these applications

 

[Jack]

TS:
To broad a spectrum for me to advise on w/ any sense of confidence ... You’re almost certainly gonna need some rod-to-cam clearance.

Big compression does not require a big cam ... but a big cam does require big compression ... require is the operative word. No doubt, big compression will benefit a lot from a big cam.

Here’s some indication of clearance ... Built a 388 w/ 3.8” stroke (0.050” longer stroke than a 3.75”) that has rod throws reaching 0.025” closer to cam that typical 3.75” stroke 383/400. Used GM 5.7” rods. An L82 clone cam (specs: 0.050”duration = I 224º/E 224º, v.l. = 0.450”/0.460”) would NOT clear rods until those rods were cut. Bear in mind this motor’s rods are 0.025” closer to its rather mild L82 cam than your 3.75" ... but it’s a reference point you might consider. Your builder can measure the clearance & cut your rods as needed. I'd still contact a cam maker ... but I like comps XE274H or XE284H grinds if you have the trans & gears & valve train ... and clearance for them.
JACK:gap

 

[tscott9330]

What is the most lift you think i could get before the grinding would cause the rods to be to week?

I have been told by the company i got the stroker kit from to go with a lift of no more than 460/480. what do you think?

 

[Jack]

What is the most lift you think i could get before the grinding would cause the rods to be to week?

There's too many variables to answer ... i.e. all rods not created equal.

I have been told by the company i got the stroker kit from to go with a lift of no more than 460/480. what do you think?

Why does vendor limit lift ... is it because the rods he supplied are not cut or cut very little ... ask vendor why?

Still ... insufficient rod info ... where'd you get em ... what are they ... what's been done to em? Does vendor have a site you can link?
JACK:gap

 

[tscott9330]

I'm not sure it will help but, here is the link Powerhouse

The rods I have are identical to those in the pics you sent

I just got off the phone with them again and they say the max cam they have seen run on there stock rods is a .500 lift but my buddy (who is very car savvy) is wanting me to go with something with a lift of .550 or so. Is that to much?

He also suggest I run at 10:1 and higher is this to much for a daily driver?

I'm a little concerned that this car is gonna be a lumbering beast, which is not a bad thing unless i can hardly drive the thing around town.


HELP

 

[AKRAY4PLAY]

running a small base circle cam would be a great idea. you need to look at the heads and see just what you can get away with because of valve spring collapse. running 10:1 with iron heads is VERY risky especially if you are going with a mild cam that does not bleed low rpm cylinder pressure. i would not go over 9.5:1 when running a low rpm cam. for $1100 you can pick up a complete set of AFR 195's that work very well on 383's. then you are free to go crazy with lift and compression. Brian

 

[tscott9330]

what is a small base circle cam? and would it allow me to run a bigger lift than would usually clear the rods?

and even if i can run a big lift like .550, should I? will it cause my car to idle bad and have problems with accessories?

Tom Scott

And by the way guys I really appreciate all this help and time you are giving me. This is my firdt engine build and I am not used to not knowing what is going on. I'm still not sure I trust my friends advice.

 

[Privategod]

In its last iteration in the January issue, we created a thumpin' small-block that made 408 hp and 430 lb-ft of torque, based on some carefully selected off-the-shelf parts. The key components were the iron Vortec heads, matched to a CompCams 268 Xtreme Energy camshaft, and Edelbrock Performer RPM intake, and a 750cfm Holley.

From an article by Chevy High Performance that tells you how they put together a 408hp/430lbs 350c.i.
Your base engine is different, but this may give you some ideas, as they list what they tried, what worked and what didn't, and how much HP/Torque was gained or lost by each mod.

 

[Jack]

I'm not sure it will help but, here is the link Powerhouse

The rods I have are identical to those in the pics you sent

I just got off the phone with them again and they say the max cam they have seen run on there stock rods is a .500 lift but my buddy (who is very car savvy) is wanting me to go with something with a lift of .550 or so. Is that to much?

He also suggest I run at 10:1 and higher is this to much for a daily driver?

I'm a little concerned that this car is gonna be a lumbering beast, which is not a bad thing unless i can hardly drive the thing around town.


HELP

TS:
Frankly ... I think you'd be pretty darn lucky if you can get a .500 lift cam in there with those rods ... and still have adequate clearance for heat growth (I like 0.050"). You'll probably be very unhappy with 10 CR on pump gas w/ iron heads ... REAL unhappy. It also appears you got PH's "CR1" rods ... it seems they are not cam-clearanced and don't even have good rod bolts.

Suggest backup & regroup before you dig a hole ya don't wanna be in. I offer this ... phone me & I'll go over a few things w/ you ... including what your budget is. Email me to setup time.
JACK:gap

 

[AKRAY4PLAY]

Tom,
base circle size is the diameter of the cam at the lobe minus the lobe it self. you think of it this way, say you have a wart on your finger that is a given height, call that your lobe lift. say that finger is your thumb, so the diameter without the wart is the thumb. now imagine you have the same size wart on your pinky, that would be a small base circle cam. sorry for the nasty mental image, but that is the easiest way i can explain the difference off the top of my head being as tired as i am. bottom line a small base circle is a smaller diameter cam that gives more clearence for either longer stroke, bigger lobes, larger rod ends or some combo of the above. big lift won't really hurt idle, narrow lobe seperation will have a serious impact though!! Brian

 

[Glensgages]

A 'small base-circle cam' has the 'base-circle' of the cam (under the lobes) a 'smalled' diameter; the lobes have a similiar 'lift', but a 'smaller' over-all dimension. This allows a big 'lift', that clears closer rods & bolts. Imagine 'wiping' the lobes off a regular, and a 'small-base' cam, both having .510" lift. Both sets of lobes spec-out at .340" on the cam (with 1.5 rockers). When the cam lobe is wiped-out (i.e.; ROUND!), the regular 'base circle' is a bigger dia than the now-round 'small-base' cam. I have the Comp Cams 292H (292*/244* @ .050"/ .501" lift) in my 10:1 355; it makes 420 HP on SUNOCO 94. It idles 'rumpity'; it'd be milder in a 383" SBC. I also have a 750 Holley dbl-pump, Victor JR, Dart II heads; I don't know your other parts. I'd think 375+ HP would be EASY in a 383"; the torque would be awesome, IMHO!!! Just my $.02 worth.....