Is the cam the limiting factor?

[Dreamcar]

I'm not having an engine built soon, but I'm slowly trying to get a more in depth understanding of how things work. That being said, I was looking at the Edelbrock top end kit for the 383 since that's the engine size I'll be having built someday.

I've searched and read a lot of 383 build threads and some are getting in the neighborhood of 450hp/450tq, give or take. Although there are many many factors, those seem like great numbers for a nice street car. The Edelbrock kit (heads, cam, intake, carb) is supposed to produce 421hp/417 tq.

The cam specs are: 238° / 246° @.05 duration, .480" / .495" lift.

I'm just wondering if the engine experts out there think that the cam in this package is a little limiting and that a slightly more agressive cam could still make this a great street cruiser but with a little more power. 

[firefighter3931]

Cam choice is critical....it can literally make or break an engine combination. 

Not a fan of that cam in a 383 or even a 440 for that matter. 

There are a lot of better choices that will make more power, idle nicer and have much better throttle response. It's easy to overcam a short stroke 383 and kill bottom end power. 



Ron

[BSB67]

The cam is a bit old school, but that does not make it bad.  I have heard from others that the Edelbrock cam actually does surprisingly well and it easy on valve train parts.  You will be more likely be able to rev the 383 to the proper rpm with a gentler cam like this. 

If you are looking to a leave nothing on the table type cam, consider an aggressive  solid flat tappet with a bit more duration than the one you are looking at.

[Dreamcar]

When getting the engine built (in a year lets say), what cam would you recommend knowing I'd like to be in the 450/450 range? This would purely be a street car for in and out of town car shows and cruising. 

I'd love to walk in the engine builders with a rough plan and some other details about the car:

383 bored .06 over;
Out of the box aluminum heads (Edelbrock RPM);
Aluminum intake (Edelbrok dual plane);
EFI (really leaning towards the self-tuning efi like Fitech or Holley Sniper);
Headers;
727 transmission with Gear Vendors Overdrive (I really want the GV);
3.55 to 3.73 gears (with the GV, this is about 2500 rpm on the highway)
27-28 inch rear tires

[PRH]

My experience with 383's that make in the 450+/- honest hp range tend to be fairly high strung.
Not really a good match for tall gears and an overdrive.

IMO, there are two possible paths for a suitable build to fit that gearing criteria.
1- put a cam in the motor that will operate happily in the powerband range that the cruise rpm is, and don't get hung up on the hp number. It is what it is. Low cruise rpm needs high TQ values at those speeds.

2- see #1........ Add stroker kit....... Easily make over 500tq/450hp.
This is by far the better choice IMO, and is absolutely the best bang for the buck for a nice power boost across the board without any negative drivability impacts.

[Dreamcar]

My experience with 383's that make in the 450+/- honest hp range tend to be fairly high strung.
Not really a good match for tall gears and an overdrive.

IMO, there are two possible paths for a suitable build to fit that gearing criteria.
1- put a cam in the motor that will operate happily in the powerband range that the cruise rpm is, and don't get hung up on the hp number. It is what it is. Low cruise rpm needs high TQ values at those speeds.

2- see #1........ Add stroker kit....... Easily make over 500tq/450hp.
This is by far the better choice IMO.

Thanks. I was giving the 432 or 450 kits some thought, but it is a little more money because of the new crank. And because the block is the original, I don't know what the most appropriate direction is to take, not that it really matters if the block and crank are all that's left. Would a Eddie 440 top end kit on a 432 stroker work well I wonder?

[BSB67]

My experience with 383's that make in the 450+/- honest hp range tend to be fairly high strung.
Not really a good match for tall gears and an overdrive.

IMO, there are two possible paths for a suitable build to fit that gearing criteria.
1- put a cam in the motor that will operate happily in the powerband range that the cruise rpm is, and don't get hung up on the hp number. It is what it is. Low cruise rpm needs high TQ values at those speeds.

2- see #1........ Add stroker kit....... Easily make over 500tq/450hp.
This is by far the better choice IMO.

Thanks. I was giving the 432 or 450 kits some thought, but it is a little more money because of the new crank. And because the block is the original, I don't know what the most appropriate direction is to take, not that it really matters if the block and crank are all that's left. Would a Eddie 440 top end kit on a 432 stroker work well I wonder?

I don't know for sure, but he might be referring to something closer to 500 cu in.

[PRH]

I would do at least the 450 rotating assy.

As has been mentioned, you can easily do better with the cam from a power producing standpoint, but the old school grinds are easier on parts and will rev higher.

Personally, I'd put a small solid in it........ Shoot for 500hp out of the 450.

[PRH]

I went through a 383 for a guy a few years ago.
Had a pretty nice build, but it didn't rev.
It had a Hughes fast rate hyd cam in it, and it was "done" before 6000rpm.
Hughes had done some big valve 346's for him that flowed pretty well, rpm intake, 1-7/8 headers, 1.6 rockers..... Nice custom quench dome pistons.

We had discussed it a few times and I felt he'd have to put a solid in it to see the potential out of the heads/intake/headers.

I installed a Comp XS282S, upgraded to Isky 8005a springs and touched up the valve seats since there was evidence of valve float going on.

Dynoed it, made 470tq/485hp..
Peak hp at 6600-ish, still 480hp at 7k.

Car is a really nice street 70 Challenger, 3.91 gears, 10" converter.
Owner likes how it revs, but isn't thrilled with the bottom end grunt.

Likes to drive the car a lot, takes out the 3.91's, installs 3.55's.
Now he really is underwhelmed by the low end grunt.

Prior to replacing the gears he borrows a set of drag radials and takes it to the track.
Kinda weak 60' times...... A completely un-sorted out car...... Runs 113mph though.
I don't recall the ET, mid-12's iirc.

Drives it like that for two seasons.
Buys a 489 rotating assy, and swaps that in along with some ported stealth heads.
Ditches the headers, I get him a different cam....... Loves it!!

Gets a little bored with it after a season and a half...... Puts the headers back on........ Loves it even more!!

Cubes are your friend.

[Dreamcar]

These are all great points. Thanks! I can't wait for that day I drop off the block for rebuild!

[XH29N0G]

I suggest sending a note for specific cam recommendations once you have fully settled on the build and drivetrain.  It looks like this is what you are doing, but as you already know the people on this forum have a very good sense of what works and why.  Good luck with your build.

[Dreamcar]

I suggest sending a note for specific cam recommendations once you have fully settled on the build and drivetrain.  It looks like this is what you are doing, but as you already know the people on this forum have a very good sense of what works and why.  Good luck with your build.

Thanks

[69wannabe]

Ron (firefighter) can give you a great cam recommendation on here. I'm not that generous when it comes to a big cam in smaller cubic inch engines. I ran a XE274 comp cam in my stock stroke 383 years back and had stock heads on it. It ran and sounded great but was sluggish on the lower end. I have 355 gears in the rear and I think if I had some 391's in the rear it would have been better off the bottom. The XE274 actually ran better to me in the 440 I put in later on but I did do some better heads and an RPM intake on the 440 too.  It's very easy to over cam an engine and to me this is one of the most done over and over again mistakes when building an engine. I always like the line " my buddy has a 700 lift cam in his car and drives it everywhere" And there are some on here with big duration high lift cams in their engines and as long as the engine recipe matches up with the rest of the build then it most likely works well.

For me a decent 230-240 duration @ 50 degrees with a decent lift like 500 to 550 works good in a street engine that you expect to drive and enjoy and like the way it sounds. In a 383 I used a XE268 cam one time for a friend I built the engine for and it had good bottom end and good sound and he loved the way it ran. Something close to this cam would be my pic for a good running 383 unless you decide to do the bigger inch stroker kit then I would go to something slightly bigger to compensate for the cubic inches.

Biggest thing is what are you planning on doing with the car? If you plan to drive and enjoy it keep your engine build mild so it will be dependable and fun without having to constantly work on it. Like said above Hp numbers are just numbers, but if that is a real goal the stroker kit is your best best and it will easier to get what you want out of it with bigger cubic inches. Good luck with the build!!!! 

[Dreamcar]

Thanks Wannabe!

[c00nhunterjoe]

The bottom end of a 383 is critical due to the short stroke. If the bottom end isnt matched right, it will be a turd. They are not as forgiving as 440s when it comes to a bad combination. Compression is key.