I'm looking at the following for the new 383 and would like to hear what others think. Anyone using a similar grind..? The rest of the combo is as follows:

All forged bottom end, neutral balance lightweight crank, 5.7 H beams, SRP flat tops, (short block already built and in the garage) Dart Pro 1's, 2.05/1.60, 215cc, & 72cc chambers. Edelbrock Performer RPM Airgap. Haven't decided on the carb yet.

Have I left anything out...?

Part Number: 118581 Grind Number: SR-240/362-2S-10.90 IG
Engine Identification:
Start Yr. End Yr. Make Cyl Description
1957 1987 CHEVROLET 8 FAIR IDLE, PERFORMANCE USAGE, GOOD MID AND UPPER RPM TORQUE AND HP, BRACKET RACING, AUTO TRANS W/3500+ CONVERTER, 3800-4200 CRUISE RPM, 10.5 TO 12.0 COMPRESSION RATIO ADVISED, .900" BASE CIRCLE FOR LONG STROKE CLEARANCE. BASIC RPM 3500-7000
Engine Size Configuration
262-400 C.I. V

Valve Setting: Intake .020 Exhaust .020 HOT

Lift: Intake @Cam 362 @Valve 543 All Lifts are based
on zero lash and theoretical rocker arm ratios.
Exhaust @ Cam 374 @Valve 561
Rocker Arm Ratio 1.50

Cam Timing: TAPPET @.015
Lift: Opens Closes ADV Duration
Intake 42.0 BTDC 72.0 ABDC 294 °
Exhaust 86.0 BBDC 36.0 ATDC 302 °

Spring Requirements: Triple Dual Outer Inner
Part Number 96870
Loads Closed 134 LBS @ 1.900 or 1 29/32
Open 358 LBS @ 1.380
Recommended RPM range with matching components
Minimum RPM 3000
Maximum RPM 7000
Valve Float 7500

Cam Timing: TAPPET @.050
Lift: Opens Closes Max Lift Duration
Intake 15.0 BTDC 45.0 ABDC 105 240 °
Exhaust 59.0 BBDC 9.0 ATDC 115 248 °

 

That's a fairly wicked cam- with the right set up it would be a very strong motor. Obviously your heads won't hold it back. You didn't mention your compression ratio, transmission type, or rear end ratio though and those could make a big difference.

 

That's a lot of info on the cam. Maybe I am missing it but the most important (IMHO) spec is missing, .050" duration

 

Right at the very bottom Motorhead- 240/248

 

Sorry Les....CR @ 10:1, maybe 10.3:1. If I went with 64cc heads I would be @ 11:1, but I don't think I will go that high. I'm wanting to install a TKO600 at the same time as the motor, if the piggybank has anything left in it. The rear is 3.70.


Motorhead....That's a lot of info on the cam. Maybe I am missing it but the most important (IMHO) spec is missing, .050" duration

Cam Timing: TAPPET @.050
Lift: Opens Closes Max Lift Duration
Intake 15.0 BTDC 45.0 ABDC 105 240 °
Exhaust 59.0 BBDC 9.0 ATDC 115 248 °


Motorhead...I was wondering what oil pan do you have on ypur 406...?

 

I would run 11:1 CR with 240/248 duration ( actually I am ), what does the manufacturer recommend for minimum compression ?

My pan is Moroso part # 20190 7qt side kickout, the 20195 is a nice pan too, my next motor will have that one.

 

You're at the lower end of their recommendation for compression but with the rear gears & the stiff 1st gear in that trans you should have plenty of gear to pull it. I run a similar tight lash solid cam in a 355 w/ 11 to 1 comp. ratio that has duration @ .050 of 244/252 and lift of .520/.540. I run with 4.10s with a Muncie 4 speed that only has a 2.20 1st gear and it pulls strong right off the line in a Z28 that probably weighs somewhere over 3500 lbs..

If you're like me and like to make as much power as you can while still being streetable I'd say you're right about where you want to be, assuming you don't want to go the solid roller cam route. If you value low end torque more than mid to high end HP you may want to step back 1 or 2 notches on the cam. That being said, if it was my 383 I'd be looking at a cam pretty much the same as the one you've picked. When all is said & done I'd really like to hear how much power that combo makes. Good luck.

 

Motorhead...manufacturer recomends 10.5:1 to 12:1.

Do you think I can go with 11:1 and still burn 93 octane..? I'm near that now with my 355ci and my duration is 230, the motor runs perfect and I have no issues with pinging.

Les...I am like you and want as much hp and tq as I can tweek while still driving on the street. This is a solid roller cam

 

OK, I didn't thoroughly scan all the cam specs- the spring requirement alone should have tipped me off. FYI my 355 runs better w/ lead additive & I run AFR 195s. As you know, your aluminum heads will help & your gas is better than the 91 octane crap we get where I live so pump gas may be enough for you. That's gonna be a strong 383!

 

I like the cam its a solid The 3000 minimum 7000 maximum
is probably based on what the cam would do in a 350 in a 383 the
range may be a little lower.

 

I run a flat tappet solid Isky Z-35 in my 406 and am quite happy with the cam. It's got 254@.050 and with my 1.60 rockers lifts .560 and has a 108 LC installed at 108.(straight up). Even with the Vic Jr,there's no loss of low end torque(It's not soggy on the bottom at all),and I have pulled 7000 in second gear,which is a rush.I actually backed off because the rpms were swinging so fast I was afraid I'd break something.
I am still putzing with the carb to get a decent idle around 900 or so.The single plane intake and huge cam makes this a bit tricky from what I've seen so far.

 

I considered the Vic Jr. and have not totally ruled it out yet. But I'll bet that you could gain 10-15lb of tq without sacrificing more than 5-8hp, which woludn't even be noticable.

Do you have tq & hp numbers on your 406...? I'd be interested to know what they are.

I'm expecting around 525 on the tq side, and maybe 515 on the hp side. I should still have decent streetability and hopefully idle around 800rpm.

phillip

 

That cam is going to be right on with tha tmotor. It could stand a little more compression but it should be OK. I was considering a roller cam in mine and that was the same figures as the one I was looking at. Someday I will go roller and probably go to a bigger set of heads also. You should be in the 520 Hp range or better with that setup.

I would definitly recomend a single plane in the Victor Jr. style intake.

 

I vote for the single plane, its a no brainer with a solid roller and run the 64cc heads for 11/1. To make sure you have no detonation use a tight quench, polished chambers, cold plugs, overdriven high volume waterpump/thermostat, high cfm fans and a cold air package.

What is the lobe separation angle on the cam?

 

Gordonm, if I go with 64cc heads instead of the 72cc I will be in the range of 11:1cr. My current 355 is in the 11:1 range and I have absolutely no issues with streetability. My car idles at 750 and the cam is a comp 280H grind. I can cruise around town in fourth gear at 1300rpm with no problem. I don't expect the new 383 to be as docile as that, but I do drive my car A LOT. I have never run a single plane intake. I would like to give it a try, but as I mentioned before, I'm still on the fence.

Someone convince me...!!!



Oh...one other thing, and this is confusing me. I ran the CR calculator and came up with 9.97:1cr w/72cc heads. Then I ran the DCR calc and DCR was at 8.36855, which is perfect. But it also calculates the static and it gave me 11:1cr with the 72cc heads. So which calculator is correct...? Am I imputing something wrong...?


phillip

 

You are probably running the same pistons I have in mine. My calculations came out with 68cc heads to be in the 10.4 range. If I were to get new heads I would definitly go with the 64 cc heads. I could use more compression. You should not have to worry about detonation with that much duration in the cam.

As far as the dual plane goes I went from the stock LT1 intake, pretty much like a RPM intake to the Victor Jr. I lost very little if anything at the low end and picked up some at the top end. Mid range was no difference. With the extra cubes of a 383 the single plane should be better on your combo.

 

I have the same Cam as GordonM, and went with Dart Pro 1 215s, shaved to 56cc, giving a 10.9 compression. No problem using 93. On tops sits a Victor Jr. Tall (w/ 1 inch riser built in) and a Holley HP 950. (Right now I am toying with spacers, and the 1 inch 4 hole HVH Supersucker seems to work best). Has plenty of low end that now requires a suspension tuning.

 

I have not dynoed,but from what the magazines read,and combinations I've stumbled onto on the web I should be in the 520-540 hp range.

My combination took me three tries to get where it is now,mainly because of "wives tales",like "You'd be better off with the dual plane for a street engine.",or "You don't want to run more than 230@.050 in a street engine".This advice may be true IF you're running a 350.Big engines need big parts. The heads,cam and intake can be sized a great deal bigger when you got the cubes.I used Edelbrock's BB RPM package as a guide for my second cam (Comp XE-284) and though it was stronger than my first cam(Comp- XE-274),I still thaught it could have gone bigger with no "streetability issues".

Just thaught I'd mention that with the XE-284 (240@.050) I ran the RPM intake and could idle at 650 in gear with a lot of fender shake.

 

Go with 11:1 CR and single plane Vic Jr. you will be happy. I run 91 octane in mine, the trick IMHO is to get rid of the vaccum advance. That is why motors ping, the vacuum advance can put you over 50 deg advance

 

Why would anyone want vacuum advance just something else to
go bad.