engine options....

[DavyZ]

Since you are going to a forged bottom end, my personal preference would be a roller camshaft assembly by Comp Cams. I could give you my own suggestions, but I don't think you will have to go too radical of a cam put you into the HP range you want. The 383 is just going to be a torque monster anyway at low rpms, and giving it a high lift cam won't help your traction anymore at all! Since you are spending a lot of $$$$ on this engine, I would use the camshaft company's help/tech line for their suggestions based on your application. You don't want to overcam a 383, because you frankly don't need to.

 

If this were my motor and I chose a flat tappet cam, I would go with a relatively mild performance cam with specs like this: intake 225 degrees at .050", exhaust 230 degrees at .050" with advertised duration of 275/285 and lift of around .5 inches. Roller cams can give you much steeper, better ramps and not adversely affect your motor's driveability. That's where their tech/help line comes in handy; get their recommendations on your application. Now again, that's for me, not you. You have to decide what you want to do with this car. If you want to race it, even that cam would be good, but you can always get much more radical. I like a streetable cam, even if the car gets raced, because I'll take it on trips with my Hunny.

 

Just my $.02--hope discussing this stuff helps you. By golly, it's certainly theraputic for me!

 

Davy

[pparaska]

One article I've read ("Cam Comparo", August 1999 Car Craft, by Marlan Davis) that say that a roller really isn't worth it torque and hp band wise on a SBC until you get into grinds above 240-250 degrees @0.050". Sure, there was some improvement from a solid flat tappet to a solid roller (14 ft lbs more in the 3500-5200 range, 8 ft lbs in the 5300-7000 range), but for the quoted increase of three times the cost, Marlan said he'd stick with a flat tappet unless the block already had hyd. roller tappets.

 

And this was for a 350 that put out 469hp@7000 with a flat tappet cam (Comp Cams 294S) and 477 hp at 6400 (still making 453@7100). This is an old single pattern roller, so a newer design would be better.

 

The hydraulic roller XR294HR-10 Extreme Energy cam made 491@6200, plummeting afterwards due to the heavy lifters and valve float. With stiffer springs than Comp recommends on the street due to longevity, the engine was able to rev higher and make a few more ponies.

 

Interestingly, Marlan said that the solid cam in a computer simulation produced better E.T.s due to increase low end torque that the solid roller had.

 

Comp Cam's take on this (Billy Godbold) was that the solid cams exhibit "artificial initial acceleration", even with the valve lash factored in. It snaps off the base circle faster.

 

Marlan winds up saying he prefers te solid flat tappet over the hydraulic flat tappet because it better maintains the powerband upstairs.

 

I'd love to see this test redone with all Comp Cams Extreme cams, since all four variations (hyd and solid flat, and hyd and solid roller) are available now. I bet that solid flat tappet Extreme cam would be damned nice. When/if I upgrade cams, I'll forgo the small hp and torque increase the solid roller gives and stick with the flat tappet, since I'll be using even smaller cams than they tested.

 

BTW, I'd think a 225@0.050 cam in a 383 would be small. Lots of torque, but it could go with a larger one with little loss of response, I'd wager.

 

[ July 20, 2001: Message edited by: pparaska ]

[DavyZ]

Pete brings up some valid points. After thinking about it, he is right that a 225 cam would be small for a 383. But, I must counter, very very streetable. Torque in abundance and the engine would not have to rev to kingdom come. However, my mind set is on my budget! You are buying good forged parts and you'll be able to rev higher than my thinking. I also forgot about the Xtreme Energy Cams they have out now--I must be tired, because those are totally hot! You might just want to look into them.

 

Whatever way you go, please let us know. Maybe I'll learn a few things.

 

Davy

 

[ July 21, 2001: Message edited by: DavyZ ]

[Guest Anonymous]

Ok folks, starting to get a little fired up for a V8 conversion. Now, I've done a little engine building before, but nothing really serious. I'm shooting for around 450 horse at the flywheel. What kind of setup should I use for a 383? Probably going to be stroked, instead of de-stroked. Probably going to be carbed, for the time being, and will be using a 6 speed. What kind of cam selection should i use, for the power, and a little bit of steet-ability. Going to balance and blueprint the whole assembly, and lighten it as much as possibly. Looking at forged pistons/rods/cranks. Thanks!

[Guest Night_rider_383]

Food for thought here.... Myself i would look and think about this if your useing the forged bottom end so it can rev high then the cam should be blueprinted to that fact. Also we aint dealing with 3300-4000 lbs chevys here. These little z's are light and a 383 is a torquer engine from the get go. Well i would say to be streetable and still hook good you wouldnt want to over power the chassis/body by building more torque down low with the smaller grind cams. In a bigger car 3300 lbs plus then yeah i would say the same thing go with what everyone knows as a street grind cause the heavy car needs more force (torque) to push it where the z really dont. and plus the fact 383's loves lift and dur. too. I would say go alot bigger than most folks would think adv.290 to 310 on how wild your building it. This is to keep from overpowering the chassis down low and give it the torque and hp where the 383 and z cars needs it Up high in the rpm

just my two cents on it