ScottyRS

iTrader: (2)

Hey guys, I'm picking a retro-fit cam kit for my 383 and need some advice. It's going into an '86 Camaro (rolling chassis at the moment) and will be street driven. But it will only see the light of day on the weekends and back and forth to shows. That being said, I'm looking for about 450hp (I'm okay with a bit more), gas mileage isn't a very big concern, and a slightly lopey idle would be pretty bad *** . I plan on using AFR 195cc heads, and a carb. I have flat-top pistons and with the 68cc combustion chambers I'll have about a 10.7 compression ratio.

Here are the cam kits. They're pretty close, but I was wondering which would be better.

And the heads.

One more thing, what will I need to keep this cam from moving around in the block? This?

Once I pick a cam, I can start ordering parts and get this damn thing together! Thanks in advance.

izcain

Your link doesnt seem to pull the cams up. The main thing I would say is if your planning on putting a hefty camshaft in your 383 make sure your rods are clearanced properly before install it otherwise the camshaft phasing will make the rods hit the cam lobes. They also offer small base circle cams as well. Just some food for thought.

Sonix

iTrader: (1)

yea, link doesn't work.
Just rattle off part #'s, maybe duration @ .050" and lift and LSA

I think you're right, you'll need that cam button, along with a strengthened timing chain cover. The beefy ones.

If your 383 isn't together yet, i'd recommend capscrews for the rods, that helps with the clearance issue.

I agree with the small base circle. Do it anyway to hopefully eliminate the issue.
Did you get around to PM'ing anyone re: this?

If you want lopey, and gobs of power, and you aren't driving it everywhere - I'd go with a compxe282HR or something similar from another brand. Like a 236/242 @ .050" or such, big lift, and something like a 106 LSA. That'll give you a real nice choppy idle (which usually is a bad thing, but whatever floats your boat), and more importantly, more powa!

ScottyRS

iTrader: (2)

The links work for me...

Anyway, Cam A has lift@0.050= 236int/242ex.

And Cam B is 230int/236ex

Both have lobe separation of 110.


Cam A will put me closer to 450hp, but Cam B kicks in at a lower RPM. Decisions...

I tried PMing a few other guys, but that didn't help much. And where would I find a beefy timing chain cover?

I found some Scat connecting rods on eBay that are clearanced for a stroker engine with cap screws.

Sonix

iTrader: (1)

This isn't a daily driver, so it kicking in earlier isn't a huge deal. Get a bigger stall speed on the convertor.

I think cam B would act similar to a 224/230 in a 350, i've got that (xe268), and it's pretty tame. Hard to tell I even have an aftermarket cam in it sometimes.

Personally? I'd do cam A, but get it custom ground to have a 106 LSA. Since you're getting it custom ground, (not a huge expense), why not throw in putting a 4/7 swap, and on a small base circle? Go all out eh?

Well, timing chain cover - instead of the $20 stamped sheet metal chromed style that I have, you need something more like the comp $90 aluminum one that's like .090" thick. There's a schwack of them, I think you just need something better than the cheesy stamped steel ones.

I'd go with H beams for the conn rods, which if they're cap screw rods I'd think they would be.

ScottyRS

iTrader: (2)

4/7 swap? Is that when you swap the firing order of the #4 and #7 cylinder? Would I need to do anything to the ignition for that? And will a custom ground roller cam work in my '73 block? What's special about these retro-fit cams?

*Edit*
The cheapest cover I see from Comp Cams on Summit is $126. You gotta be kdding me.

*Double Edit*
Milidon makes one for $30.

Sonix

iTrader: (1)

yep, that's what a 4/7 swap does. I wouldn't recommend doing it just for the sake of doing it, but if you're already getting a custom ground cam, then it's "free" in that respect.
Oh yea, major changes in the ignition needed... You have to pull your #7 spark plug off your dist cap and swap it with #4. Super easy 9 second mod right there.

Yes, a custom ground roller cam fits the same way any other **retrofit** roller cam will fit. Get it as a "retrofit" roller, and use the retrofit roller lifters. The small base circle thing - you just have to make sure the lifters are ok for that, so they don't hit the link bars on the lifter valley surface. Ask comp/crane/whoever is custom grinding it, about that little issue. May need taller lifters, but I don't think so. Again, i'm no expert on that, just know that you should think about it.


Yea, $126, that'd be the one.
Might want to post the milodon one for $30, I think that'd be a little weakie guy... (for that price...)

ScottyRS

iTrader: (2)

Okay I assumed that's all that would be necessary for the 4/7 swap. And the Milodon cover says it's made of .090" thick wear plate and is designed to provide a positive cam stop just like the Comp Cam one.

Milodon Steel Timing Covers: MIL-65555 - summitracing.com

But which cam button do I use? Or am I going to have to measure it once everything is together?

It seems I'm getting more questions than answers.

Sonix

iTrader: (1)

ah yes, just a cheesy stamped plate. It's not .090" thick throughout, just has a .090" wear plate. So a good strong load on it, would still deflect the whole plate. That's my guess at least.

Well I think i've shoveled out all the know-how that I have WRT retro-roller setups, i'm going to have to bow out to the knowledgeable guys here.

ScottyRS

iTrader: (2)

It's greatly appreciated.


And could I reinforce it myself? Because I sure as hell ain't paying $126 for a timing chain cover. Unless it's made of solid gold. And even the Comp Cam cover says theres just a welded-in tab for the cam button...

Confuzed1

iTrader: (4)

Try this link: Converting a Hydraulic-Roller Camshaft - Tech Article - Chevy High Performance Magazine

It may have a few answers for ya. I just got done doing this myself about 4 months ago. I couldv'e done it a little cheaper myself.....but not much. PM me if you have any Q's.

ScottyRS

iTrader: (2)

Well, looks like I'm getting an Edelbrock water pump.

Sonix

iTrader: (1)

haha, yea, I read that article and that's what I thought... Until I remembered the price on those... I think it's over triple what a normal water pump costs. If you go that route, be sure to get the good one, like the high flow one or something.

ScottyRS

iTrader: (2)

Yup, might as well get it polished too...I was planning on buying one of those anyway. At least now I can kill two birds with one stone.

izcain

I've heard that those 4/7 swap cams produce a lot more power then just a standard cam, has anyone here ran a 4/7 with the same lift for comparison? just curious.

ScottyRS

iTrader: (2)

I think they only give you a few more horses. At least on a street engine.


And I just talked to Comp and they said they can't do the 4/7 swap on a hydraulic roller cam. Oh well...

Comp788

Ixcain,

I have run many 4/7 swaps in my front enging dragster. We run a 406 on alcohol that makes close to 850hp. In my experiance I did not see much of a difference with the cam swap. I have run the exact cam except one with a 4/7 swap and the same day at the track but in the non 4/7 swap. They bouth ran with .02 tenths of eachother. We use the 4/7 swap in the draster strickly for heat issues. We run the block and heads without water. Obviously you can't do that on a street engine but in a race only application you can. Now I do have friends who run the 4/7 with a gas motor and it makes quite a few more power due to the scavenging of the exhause in the headers. The dragster uses zoomies.

Now several of you guys were talking about small base circle cams. While they help with clearance issues when you decrease the base circle dia of the cam the cam ends up twisting more. We went to a raised cam and a 55mm dia. cam in the dragster and picked up over 2 tenths. Obviously when you run higher spring pressures you end up with more loading on the cam. That causes more cam twist. On a street engine you probably would not even know it is happening. But I have seen small base circle cams tat have been ground off center becaues they know the cam will twist under load.

This is a complex issue. If you were to call up crane, comp, or any of the main cam placed. The tech guys that answer the phone would probably tell you that they have never heard of this. Now if you talk to the true cam guys at that place. they know exactly what I am talking about. This is mostly something that you deal with when your building an all out race motor. They is why they offer raised cam blocks and 50, 55, and 60 mm cams.

Comp788

ScottyRS,

Anything can be done with camshafts. It just depends on how much you want to spend. Usually you have to get a custom core. That would be made froma big billet stock, then have it ground to a core, then have it finnished ground. Something like this runs $600 to $1200. I know as we had it done when we made the cam for the Ford-O-Let. It is a one off prototype engine that my machinest built. The Ford-O-Let is a 408 chevy with 351 cleveland heads.

izcain

Comp788 so your saying that in your experience youve seen a noticable improvement on street engines but not so much on track engines? I was contemplating using one when I swap cams on my 383 but im not sure. Even if it is only a couple of horses it would be worth it to me.

ScottyRS

iTrader: (2)

Well, I asked the guy at Comp Cams if they could make me a small circle base, retro-fit hydrualic roller lifter cam with the 4/7 swap and he said they can't do the 4/7 swap, for whatever reason. I'm really not too concerned about it so I didn't press the issue.

Comp788

Izcain,


I would say that you will see some improvement on street and quite a bit more on a race motor. What I was saying is that on my dragster it did not make much od a difference due to the injection and zoomies. The 4/7 swap had more value when your using a collector header. You will see a improvement on using a 4/7 swap. They have been using it in prostock and comp eliminator motors for over 12 years now. There is a reason that they do it. The reason is it makes more power.


You need to realize that when you run a injected motor in alchol with zoomies it is like having 8 one cylinder engines. Each cylinder is tuned seperate.


ScottyRS,


The reason that they said no was you were just talking to one of the tech guys. They field hunderds, if not a thousand of calls a day. They look as it as 99% of the phone calls to the tech line as tire kickers. While that is not the case that is how your treated. When you need a truely special cam or project you have to talk to the main guys. Contacts like that are made at the PIR show or at the NHRA National Events. Of coarse if you engine builder is a WD then he probably has a contact with one of the major cam suppliers.


It is possible that they just did not want to make a small base circle cam. Most of the cam manufactures are really trying to get away from them. They flex way too much!