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Topic: Vortec 383 stroker cam selection

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Vortec 383 stroker cam selection (1/14)
6/5/16 5:14pm

daveo76
Former Member
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Vancouver, WA - USA

Vette(s):
1976 Silver/Firethorn. L48, 4spd. Original 2 bolt, vortec heads, 9.4:1 CR, Speed Pro Cam: 224/224@0.050, 112 LSA, Eagle Steel Crank.

Joined: 8/25/2005
Posts: 857

Full Disclosure here, guys: this post is not about my Vette it's about my '91 Suburban that will soon be getting the motor in the description. But I posted here because most of the info exchanged would at least somewhat apply to someone putting a similar motor in a Vette, with a caveat or two. If it needs to be moved, though, I'm OK with that.

Background: in the parts gathering phase for a stroker motor for my Burb. It's a '91, 3/4 ton, 4x4, that will mostly see light "family excursion" duty, but I want it to be able to tow about 8K lbs without too much of a problem. 4L80e tranny. I have a 4-bolt block that I'll get bored and clearanced for a 383 rotating ass'y kit. (Scat or Eagle). I'm shooting for 9.5:1 CR. I've got some professionally rebuilt 062 vortec heads, and I have the GMPP 4-barrel intake for those heads. Now here's the caveat I mentioned above: I'm going to run the original throttle body injection (TBI) system and related in the burb, don't want to go to carb because of the electronic tranny. So I have an adapter for the TBI to the 4 barrel manifold and I also got an enlarged throttle body to use since I'll need more air for this bad boy. (I'll probably also have to upgrade the fuel pump because more air means more fuel). I know I'll have to get a chip burned - I'll use Old School EFI to help me with this as he's right in my home town of Vancouver, WA.

Here's the crux of my post: trying to figure out what cam to use. The TBI truck blocks did not have roller cam, but they had all the provisions for them so good news there. Along the way I also bought a core vortec motor for the heads and roller valve train. My plan right now for the cam is to just get the L31 stock roller that came in the core motor cleaned up by a cam grinder and use that. Along with the roller lifters and other valve train parts ("spider" and keepers). Is this a bad plan? I know the hot rodder types will say I'm leaving too much power on the table by using the stock vortec cam, but I'm not looking for high HP numbers at high RPM, just want a good cam for a heavy 4x4 truck. Also looking for decent economy although I know that is probably a pipe dream! I have thought about the 383HT/ramjet cam, but I'm worried the 109 LSA is too tight for the TBI system, even with a chip. Feel free to throw rocks at my plan, but offer other suggestions, too!

Sorry for the long post but I thought it would be useful to post on this site. I could post on other forums, but you seem to run into a lot of opinions that are often not well thought out and may cause more harm than good. I know there are a few of you here that can probably offer some good advice without too much rhetoric and flaming to go along with it. Thanks.

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1976 Silver/Firethorn. L48, 4spd. Original 2 bolt, vortec heads, 9.4:1 CR, Speed Pro Cam: 224/224@0.050, 112 LSA, Eagle Steel Crank.

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Re: Vortec 383 stroker cam selection (2/14)
6/6/16 1:05pm

Adams' Apple

Lifetime Member
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Duncanville, TX - USA

Vette(s):
#1-1974 L-48 4spd Cp Med Red Metallic/Black deluxe int w/AC/tilt/tele./p/w-p/b/ Am-Fm/map light National/Regional/Chapter NCRS "Top Flight" #2-1985 Bright Red/Carmine Cp.L-98/auto Member: NCRS, NCRS Texas, Corvette Legends of Texas

Joined: 11/8/2003
Posts: 20128

Neat plan....I think.... LOL

A stroker engine will already increase the available torque, so that will be an advantage on the big 4x4, even with the stock style TBI set-up. You'll definitely need some programing done to make it work. As far as what cam to use....not a clue here. The stock Vortec cam might not be enough to take any advantage of the stroker engine, tho....it might not run very well at anything more than idle....but the again it might. What I would suggest is getting in contact with Lunati, or Comp Cams, and let them run the data thru their cam selector program. Tire size, gear ratios, etc, will make a big difference in what cam might or might not work. I kinda agree that using a stock type cam on a stroker is sorta going backwards, tho....you need something a little more aggressive, but still produce the torque you'll need at low/mid-range. Chances are, there is a cam for a 383 designed for an RV out there somewhere....that's what you need. Approve

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Joel Adams
C3VR Lifetime Member #56
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Re: Vortec 383 stroker cam selection (3/14)
6/6/16 4:57pm

Thanks for the advice, Joel - I really appreciate your input. One thing I forgot to mention about my plan (yeah, I know - how could he have forgotten something in that long post??): I was thinking about going to 1.6 ratio rocker arms vs. stock 1.5. That would give me some increased lift without changing LSA or duration per se. Thoughts if this would help increase the aggressiveness in the area I would need for the stock vortec cam?

But you're right, I will definitely be calling COMP or Lunati and asking for them to give me some suggestions. Perhaps I would be able to compare the specs of their suggested cams to the stock vortec and go from there.

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1976 Silver/Firethorn. L48, 4spd. Original 2 bolt, vortec heads, 9.4:1 CR, Speed Pro Cam: 224/224@0.050, 112 LSA, Eagle Steel Crank.

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Re: Vortec 383 stroker cam selection (4/14)
6/6/16 10:23pm

Adams' Apple

Changing to the 1.6 rockers will help on the top end(rpm) for sure. You have to be very careful using them....the spring clearance needs to be checked/double checked to make sure the valve springs will not bind at max lift, and the valve/piston clearance needs to be verified. Since you mentioned using roller rockers, then you won't have to worry about the rockers themselves binding on the studs(at max lift), as you would with a regular stamped steel rocker.

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Re: Vortec 383 stroker cam selection (5/14)
6/7/16 2:06am

Thanks again, Joel. Just submitted my online cam advice form to COMP. We'll see what happens.

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1976 Silver/Firethorn. L48, 4spd. Original 2 bolt, vortec heads, 9.4:1 CR, Speed Pro Cam: 224/224@0.050, 112 LSA, Eagle Steel Crank.

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Re: Vortec 383 stroker cam selection (6/14)
6/10/16 3:59pm

nosal1
Former Member
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Dunedin, FL - USA

Vette(s):
1980 Corvette Torch Red with Gold metallic 370HP/350 CU.IN.Turbo 350 w/shift kit.Originally CA.Car with 305 CU.IN.

Joined: 3/21/2006
Posts: 262

Daveo76...One suggestion is to get a Melling cam catalog or go to website or call and talk to a rep there. I have successfully used their regular hyd. cams and roller cams without any problems,and almost half the price.

One such cam I used they supply is a cam with a gross lift of .488 intake and.509/.510 standard hydraulic and also have this same GROSS LIFT in a roller cam in the event you go roller cam/lifters..I don't have in hand their part numbers for these cams,however they will have them listed.

Good luck with your build..

Sal C nosal1

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Re: Vortec 383 stroker cam selection (7/14)
6/14/16 3:08pm

$89.95
Qty:
SUPER 383 camshaft for standard flat tappet cam ..Sal

California Compliant No
Cam Type Hydraulic
Computer Controlled Compatible No
Exhaust Valve Lift .509 in
Ext Center Line C/L 117
Ext Rocker Arm Ratio 1.5
Ext Specs@.050 Cam Lift Duration 244
Ext Valve Lash Clearance HYD.
Grade Type High Performance
Idle Rough
Int Center Line C/L 107
Int Rocker Arm Ratio 1.5
Int Specs@.050 Cam Lift Duration 234
Int Valve Lash Clearance HYD.
Intake Valve Lift .488 in
Lifter Type Hydraulic
Notes Stage II. NOT CALIFORNIA COMPLIANT. NOT COMPUTER COMPATIBLE. . GROSS VALVE LIFT .488 INT .509 EXH; CAM LIFT

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Re: Vortec 383 stroker cam selection (8/14)
6/14/16 10:10pm

Adams' Apple

That looks like a pretty healthy cam right there! Oughta work just right with a 9.5 cr....duration's not overdone, but it'll still have a decent lope and still be driveable. Definitely need to check spring clearance at max lift on it, but it appears to be a really good choice for the application. Thanks Sal! Thumbs Up

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Re: Vortec 383 stroker cam selection (9/14)
6/15/16 2:19am

Yeah, thanks for the tip, Sal. I have no problem with going with Melling or similar. I think with Comp, Lunati, Crane, etc. you're paying a lot for the name. Notice my sig - I have a Speed Pro in the Vette. I have had no problems in 5 years, although I do use good oil (Joe Gibbs Hot Rod) Is there a connection between Melling and Speed Pro? I seem to remember some connections between some of those engine parts outfits.

So the cam you posted won't work for what I want to do since I'm converting to full roller, but the specs are pretty close. Also those lift numbers are generally too high for stock vortecs, but there are things that can be done to make them work. I need to call the builder that did the heads I have to see if they machined them for higher lift cams.

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1976 Silver/Firethorn. L48, 4spd. Original 2 bolt, vortec heads, 9.4:1 CR, Speed Pro Cam: 224/224@0.050, 112 LSA, Eagle Steel Crank.

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Re: Vortec 383 stroker cam selection (10/14)
6/15/16 4:06am

Hello Joel/Daveo and good morning.I have built several 383 over the years with much success,in fact Vetter Bob has one of my 383's in his '69 Vette.

I have another suggestion and that with flat top pistons from Seal Power,again I do not have the part # nevertheless with their pistion and 64 cc combustion chambers or slightly less(60 cc) you will have 10.77-1 compression and a very nice lope to the engine.Also suggest a stall converter of 25oo-2800 rpm (summit racing)stocks what Daveo needs. Also Z28 valve springs PN VS739R good to 1.70 installed height and a gross lift of .550 max.

If possible another suggestion is either "PIN" the rocker studs or replace with screw in studs (expensive but desired)..I don't know if the block has been machined in the area of #7 and 8 cylinders to clear rod bolt nuts,but be sure this is checked,i.e.install rods/pistons and rotate to check clearance of material in block of the rod bolt nuts. I mentioned this as I do not know what has been done to date.

Daveo Good luck with your build and great success. Sal C nosal1

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Re: Vortec 383 stroker cam selection (11/14)
6/15/16 7:07am

Daveo/Joel FYI on 062 casting heads. These heads are very prone to cracking in the exhaust area of cylinders 3/5 4/6..

I should have mentioned this in the last memo,however missed this bit of info.

They have a great combustion chambers but not trustworthy. Again good luck..

Sal C

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Re: Vortec 383 stroker cam selection (12/14)
6/15/16 7:26am

Sorry for the additional memos/thoughts,however I feel this is very important on your build and that is if you use different heads or even use the 062 have your machinist open the exhaust ports too fit 1.6 or 1.65 diameter valves as it is important to rid the cylinders of exhaust and will also be advantages to use headers with 1 5/8" or 1 7/8" tubes to 2.5- 3" collectors for increase torque.It is a mistake of most guys who think having 2.02 intake valves are conducive to hi performance when faster exhaust system is more beneficial,unless you have dual quads or a 1100 CFM carb then you would need both..

Sorry for the many memo's however felt this was important... Sal C

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Re: Vortec 383 stroker cam selection (13/14)
6/16/16 2:30am

Sal, all good info, especially for someone building a 383 for, say, a C3 Vette. Smile

But in the case of my 'burb I think we're talking too much motor here. I'm shooting for 9.5 ish CR - 10.77 is way too high for what I want to do. The early 90's TBI system will be a limiting factor for me, even though I have upgraded the throttle body and will upgrade the fuel pump and chip, that system can only go so far.

Yep, I know about the 062 casting concerns. I've dealt with cracked vortecs before, both when I put them on my Vette and now for the burb. The machinist that sold me the ones I will put on the burb supposedly has upgraded the exhaust seats, but my philosophy is to just never let them overheat. And no headers for this rig. Don't want the engine bay heat, starter concerns, loosening bolts, etc.

If GM had ever done a production 383 for 3/4 and 1 ton trucks in the mid to late 90's - I think the motor I'm going to build would look a lot like that.

______________

1976 Silver/Firethorn. L48, 4spd. Original 2 bolt, vortec heads, 9.4:1 CR, Speed Pro Cam: 224/224@0.050, 112 LSA, Eagle Steel Crank.

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Re: Vortec 383 stroker cam selection (14/14)
6/16/16 5:12am

Daveo76 FYI the 383 stroker engine got it's start as a Blazer engine in Mud Racers in CA. then became an engine used in El Camino's, Cheveles,Camaros and then in Vettes,however gained their fame in Suburban's,Blazers and trucks with EFI,TPI induction systems.

Take care and good luck.. Sal C

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Topic: Vortec 383 stroker cam selection

in Forum: C3 Engines

Daveo76...One suggestion is to get a Melling cam catalog or go to website or call and talk to a rep there. I have successfully used their regular hyd. cams and roller cams without any problems,and almost half the price.

$89.95Qty:ADD TO CARTSUPER 383 camshaft for standard flat tappet cam ..Sal

Hello Joel/Daveo and good morning.I have built several 383 over the years with much success,in fact Vetter Bob has one of my 383's in his '69 Vette.

Daveo/Joel FYI on 062 casting heads. These heads are very prone to cracking in the exhaust area of cylinders 3/5 4/6..

Daveo76 FYI the 383 stroker engine got it's start as a Blazer engine in Mud Racers in CA. then became an engine used in El Camino's, Cheveles,Camaros and then in Vettes,however gained their fame in Suburban's,Blazers and trucks with EFI,TPI induction systems.

$89.95
Qty:
SUPER 383 camshaft for standard flat tappet cam ..Sal