and since its goina be on a .9" base circle (sold roller) I can choose any specs I want for it.

I already have a good idea of what I want, but since I've never build a 383 before I could be off a hair or two.

its goina be a daily driver. 3.23-3.42 gearing, Th350 or 700R4 with stock or near stock stall. ITs goina have a blower too... a smal 142 weiand for about 5-6 PSI of boost. 9.5:1 compression, AFR 195CC Heads.

I beleive I've got the components matched pretty well. now its just time to order the cam. Im ready. Hit me with some specs for this daily driven monster.

 

IMO
you want to keep the LSA on the wide side of 112 to 114*
along with a relatively short intake duration between 220 and 224*
add about 10* duration to the exhaust (maybe less)

I'd keep the lift up between .600 and .650 with those heads


It's generally said that moving up (advancing) the valve opening events a few (maybe 5*) degrees works well on blown engines... starts getting the exhaust cleared out a little sooner since the cylinder pressure at BTC power stroke is very high on a blown engine.

actually, this may be a good one for Vizard to spec out if you want to spend the $35

 

Lift will tend to max out in the .56-.58"
That blower is really designed for low rpm.. use a cam designed to maximize the same. LSA 110-112 max.

 

Just asking, but if this is gonna be a daily driven 'monster', why are you going with the low gears, and the stock convertor? It seems mild to me.

The 350 and 700 are worlds apart in gearing.

What induction system?

Why a solid roller if it's daily driven?

 

Well well well Yes i beleive I've got the right idea to begin with then.

You cannot get a hydraulic roller in a .9" base circle cam.

The heads max at .550 Lift

Even with such a mild combo (low stall / gears) it should still be in the 500-550 horsepower range and run high 11's with the right 60' times.

the TH350 is for starters until I can get my probuilt 700R4. thus the 3.42's to keep cruising RPM down. I do alot of highway driving.

But anyways, back to the original quesiton, my blown 355 loved the 218 / 224 @ .050 110 LSA, so im going slightly bigger @ .050 slightly lower on the advertised (roller) to make up for the extra cubes.

Ill probably hit a 224 / 234 @ .050 with a 112 or 110 LSA, most likelly below 265* of advertised duration if i can help it.

 

Why do the springs max out a .550" lift? Are they hydraulic flat tappet springs? I still think you need to put better, atleast dual springs with .600" lift.

 

got one myself.

 

comp cams (somtimes i wonder about them) said that with a .9" base cirlce you cant have hydraulic roller lifters because the lifter oiling hole falls to low in the lifter bore.


<b>Why do the springs max out a .550" lift?</b>

Because thats what the AFR 195CC Heads come with.

Supposedly I cannot go over .550 lift anyways because that will move the lobe too close to the crankshaft rod bolts and it will break my cam in half

 

You definitly have to change those springs if your going to run a roller cam.

This is straight from the AFR website.

1.450" OD Hydraulic Dual Valve Spring, 120 lbs. on seat, .550" maximum lift, AFR #8020

You can't use them with a roller because they won't hold the valve anywhere. Very bad idea, IMHO!!

 

HUH? Comp cams just said I COULD use those springs. How do you know they wont work?

 

You can run them if you want, but you will run into sever valve-float problems at relatively low rpm's.

 

Right I got that part. But how do you know?

<b>1.450" OD Hydraulic Dual Valve Spring, 120 lbs. on seat, .550" maximum lift, AFR #8020 </b>

Doesnt say anything to me. Whats it telling you that its not telling me?

Your telling me the valves will float easilly? why?

 

Because that spring is designed for fairly mumdane cam grinds such as a hydraulic flat-tappet lifter. A solid roller cam has much more violent valve action, which is why they make more power, requiring a very strong sturdy spring to control valve action.

Just look at them 1.46"od with 120# seat pressure. Then look at a spring desinged for solid roller cams like these comp dual springs 1.550" od 240# seat, 598# open.

 

The spring is rated at 155lbs at 1.85" setup height. There is also a hydroller rev kit for as little as 90bucks..
http://www.competitionproducts.com/page56.html

I have built many hydroller motors that pull 7000... proving that old 6000 rpm limit obsolete.

PS, i have a hydroller that has .6" lift with 230degrees duration (not the one thats in the 400now..). Not exactly what I would call a mild ramp.

 

Leigh's right. Flat tappet springs won't have the necessary open pressure to control a roller cam in most cases. Check with your AFR salesman to be sure.

Putting that aside.... roller cams are completely different beasts than flat tappet cams. A 224* @.050 roller cam is a much wilder cam than a 224* @ .050 flat tappet cam. Rollers don't get the valve from zero to .050 as fast as a flat tappet, but once they reach .050- WATCH OUT!! They move that valve FAR and FAST. Hence, the need for stronger springs.

If you switch from a flat tappet 224/230 @.050 flat tappet cam to a roller 224/230* @.050 cam you will make more power but at a higher RPM and at the expense of street manners, idle vacuum and all the usual "big cam" gotchas. DON'T just compare at .050 duration!!!

If you compare roller cams to flat tappets at their ADVERTISED durations you will be much closer to comparing apples-to-apples in terms of idle vacuum, driveability, power, RPM range and such even though the roller will actually have less .050 duration than the flat tappet at any given advertised duration! From that point you can decide how much further you want to "stretch the envelope" and trade street manners for power.

A roller cam with the same advertsed duration as a flat tappet cam will make a little more power but also exhibit slightly better manners- idle vacuum, low end torque, etc. Rollers allow you to stretch the envelope A LITTLE, in all directions, but don't go crazy. And don't just compare .050 duration specs- they don't tell the whole story.

A mild .050 spec on a flat tappet cam is much wilder (in all ways) when applied to a roller cam. Call the cam compaines and talk it over with them before you choose.

 

Damon your right, But your also wrong in this case for me. But thats not because your wrong, its because I gave the wrong information.

Leigh your also right but wrong. I gave the wrong information so you misunderstood.

Maybe you ppl can help me figure THIS thing out now.


I called CompCam and Holley (lunati) Cams and Even Crane. I also called AFR.

They all told me the same thing. with a Hydraulic Roller cam the springs the AFR's come with (120# Seat) Are perfectly FINE for the Grind the Comp Cams Guy recommended. No need to change.

But thats because I said Hydraulic Roller.


Check this out:
My Flat tappet XE262 Cam has 218* @ .050 and 262* Adv. Right?
The Camshaft, Hydraulic ROLLER XE270 has 218* @ .050 and 270* Adv.!!!
<b>even though the roller will actually have less .050 duration than the flat tappet at any given advertised duration!</b>
Thats exactly what Damon said. makes sense to me now.

Its even MORE mild than my FLAT TAPPET cam, and its a ROLLER!

Now look at this cam:
282 / 292 Advertised, 255/265* @ .050. Very very fast ramp. THATS a Solid Roller grind. That one has over .600 lift and requires "Triples" for springs.

I know about the changes from roller to flat tappet, But it appears the <b> common Off-the-shelf, specifically XE series from comp</b> Hydraulic Roller grinds are just as Docile, if not more docile, than the flat tappet grinds.

Thus the companies agree, flat tappet springs with 120# seat pressure will work fine.


I guess my next issue would be Do i choose the XE270 cam for my blown 383 like that guy recommended (which doesnt look bad)
Or do i get bigger springs, and get a custom hydraulic roller grind with a much faster opening/closing rate?

It turns out im stuck using 1.050" base circle cam hydraulic roller for this motor. Not going solid. see? misinformation for you. Sorry wont happen again

 

No all roller cam grinds are more aggressive then there flat-tappet counterparts. The advantage is that you get more duration at lift then a flat-tappet cam, this is because the cam lobe is more aggressive design. As an example, a solid roller with 234 degrees at .050 is creating a lift of a whopping .640". You would need at least 280 degrees at .050 in a flat tappet cam (@320 adv. dur.) to provide enough ramp to get to .640". With a solid roller, I can open the valve faster and higher, hold it open
longer and close it faster(because I can use significantly higher spring pressures without lobe wear problems). As a result the profile becomes more square then the solid flat tappet mechanical cam. Ergo, the area under the curve on an optimized solid roller is greater than ANY solid flat tappet cam of comparable duration.






Also having less seat duration is a good thing it make the cam seem more docile and have better streetability.

 

Alright. so solid rollers are cool.

What about hydraulic rollers? What should I shoot for? Is everyone right about my springs for a roller hyd. cam? they will work huh? I emailed (as opposed to called) AFR's Tech to make sure they are right. I dont want to screw this motor up, Im doing everything right. If i gota change springs, however, Im goina go heavier and go with a bigger roller cam. Should I do that?

Or should I just run the XE270 on a 1.050 base circle like comp recommends.

 

I have a comp cams hr314 /600 installed in my 383, but it's not going to be very streetable. It needs at least a 3500 converter and 4.10 gears. What I didn't get is 314 advertized is only 252@ .050. It's ground on a 1.050 base also, had to grind .060 off of the rods to clear. HR cams don't need the seat pressure that SR cams do. Be very careful with the setup on the springs. Don't go by comp cams web site on setup. I found out the wrong way, after buying all the parts. I ended up useing the +.050 locks because I already bought the valves, and didn't want to buy a second set of +.100 long.

 

The information that i provided was for hydraulic rollers and is the same for solid rollers.

I would run a very mild roller cam because you have a blower and weak springs. You want a small came with little overlap so that all the boost pressure is not lost out the exhaust. Try a XE268HR with 112 - 114 lobe seperation angle. It should be fine because you have a 383, with a long stroke so you don't want to rev it high anyway.

 

Or go with a

Crane
PowerMax
Hydraulic Roller
HR-276-2S-12 IG

http://www.cranecams.com/master/apps...1.%20Hydraulic

Its the 1st one there.