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BorderGuy
05-20-2010, 08:47 AM
Anyone have a source where I can compare lift, duration etc among the various VORTEC SBC camshafts?

Would like to compare a 305 VORTEC cam against the various 350 VORTEC grinds. Apparently there is a different grind for light vs heavy (GVW) 350 VORTEC truck engines.

Again I need specific data to compare with the intent of shopping around for an aftermarket manufacturer of both roller and non-roller cams.

Thanks

Pauly
05-20-2010, 01:29 PM
The Vortec 350's/305's all use the same cam grind. In fact the B/D body Lt1 350's and B/D 4.3V8's use the same cam as the vortec 305/350's do.191║/196║ 0.414"/.428" lift on a 111║ LSA.

The 3/4 ton and heavier trucks came with larger headpipes that connect the manifolds to the larger cats, the 1/2 ton trucks got smaller 1 7/8" headpipes and smaller cats. The Vortec 305 used a single cat y pipe setup, while the Vortec 350 used a dual cat dual headpipe arrangement.

There are 3 Vortec 350 engines
L31 LD under 8600 lbs gvrw2 bolt mains p/n 12530282
1996-2002 CHEV/GMC EXPRESS, SAVANA (G1,2)
1996-1998 CHEV/GMC PICKUP, SUBURBAN, TAHOE (CK1,2)
1999-2000 CHEV/GMC PICKUP, SUBURBAN, TAHOE (CK1)

L31 HD over 8600 lbs gvrw 4 bolt mains p/n 12530283 for vans/trucks
1996-2000 CHEV/GMC PICKUP,(C/K2,3)
1996-2002 "G" Van, Savannah,Express Vans/1996-1999 "P" Vans- Over 8,600 GVRW 96-00 CK2,3 G (L31) 99 P3 (5.7R) CPI HD

L31 p/n 12569010 This L31 is almost $4000 new, the previous 2 are around $2000 brand new.
1996-2003 W4


peace
Pauly

BorderGuy
05-20-2010, 02:16 PM
Pauly:

Thanks..one of the best responses I have gotten in a long time. Was looking for a VORTEC (350) cam for my truck project and already have (2) 305 VORTEC cams in my parts bin..guess I can use either one.

My block is a 1994 350, 4bolt truck engine that I 'm converting to roller & possibly a VORTEC cam..will top it off with a speed density TPI. Building a 3500Hd toy with a 4.63 geared rear, NV4500 (5.61 first gear) and 19.5 tires...about 6000lbs (plus) empty.

Was hoping that there was a better VORTEC 350 grind and still considering the Comp Cams 08-407-8 Grind XR252HR, .472 intake and .480 exhaust lift, but really don't want to spend $300 just for a cam:nono:. Running stock swirl heads (1.94/1.50) and stainless shorty headers. Kinda building a tug boat on 6 wheels.

Thanks again..

Pauly
05-20-2010, 06:51 PM
No problem,
there is the HT383/Ramjet350/marine roller cam(p/n 14097395) that has specs of 196║/206║ 0.431"/0.451" on a 109║ LSA that would also work well for you.

The LT4 cam from a production 1996 LT4 Corvette(p/n 12551142) has specs of 203║/210║ duration at 0.050" and lift of .446"/.450" with 1.5:1 rockers(.476"/.480" with 1.6:1 rockers that the LT4 engine uses) on a 115║LSA. The LT4 engine has short 4" intake runners and uses a 6412 rpm rev limit in the PCM. I know folks that run this cam on TBI V8's and like it.
Its all in the ECM tuning.
These roller cams can be had for $50-$100 on the internet, sometimes as takeouts.
The L30/31, iron head LT1 and L99 4.3 roller cam is much better than the TBI cam that was in your engine.
Running TPI will give you all the low-mid rpm torque you want.

1987 TPI 350 roller cam has specs of 202║/206║ .403"/.415" lift on a 115║LSA (p/n 14093643)

1995-97 LT1 5.7 specs are 201║/208║ .447"/.459" (p/n 12551705)

Your final 1st gear ratio will be 26:1 (5.61 1st gear x 4.63:1 rear gear) which will pull a house down. Sounds like a fun project.

peace
Pauly

BorderGuy
05-20-2010, 07:34 PM
Again..great stuff...I have it documented for reference. Sounds like you have access to some GM data. Let me ask you one more cam question, I had a very low mileage crate engine that was installed under warranty in a 1988 Caprice Police with 5.7 auto... "carburated" with a Quadrajet on 305 (58cc heads) 2 bolt mains ..all OEM....the civilian version had TBI.

GM was having trouble with the 1988 Police 350 blocks cracking inside the lifter valley. Later they reinforced the casting and the cracking stopped. I picked up the engine with under 35K miles, (no numbers stamped on the pad) and stored it in my barn. A couple years ago intending to use the engine..noticed that the water jacket cracked and it was stored empty..go figure!!..so I just parted it out for my other engines.

The cam in the block is a roller and if I remember...mics around the same as the VORTEC 305 cam I have. The only stamping on the cam is the number 156 stamped on the back. Since it was in a carbed engine I would like to know the LSA to determine if it is ECM compatible.

Have anything on this roller cam?

Thanks

Pauly
05-20-2010, 07:55 PM
I dont on this cam, maybe fast305 will. He knows the older cams better than I do.

peace
PAuly

BorderGuy
05-20-2010, 08:36 PM
Thanks anyway..maybe someone will jump in with some info.

Ed

Fast305
05-23-2010, 06:41 PM
I dont on this cam, maybe fast305 will. He knows the older cams better than I do.

peace
PAuly

156 stamping is the TBI Peanut Roller cam.....305 TBI, some 305 TPI, and civilian 350 TBI B/D body cars..... It specs something like.......179/194 @ .050, .350/.385" lift, 109* LSA....Its a TINY cam for a heavy cruiser with OD and 2.xx gears.

BorderGuy
05-23-2010, 07:23 PM
Thanks Fast305

Looks like I have another one for the shelf..at least I can include some specs with it's lable.


Thanks all!

BorderGuy
06-03-2010, 08:49 PM
Pauly

There is a cam you suggested (HT383/Ramjet350/marine roller cam(p/n 14097395) on eBay right now at:

http://cgi.ebay.com/ebaymotors/GM-Performance-Camshaft-14097395-HT383-Ramjet-350-New-/280512479947?cmd=ViewItem&pt=Motors_Car_Truck_Parts_Accessories&hash=item414fd8c2cb

It is listed as "non computer cam" can I make it work in the TPI engine?

Pauly
06-06-2010, 09:06 PM
If it can be made to work in the Ramjet 350, then yes it will work on your TPI.
Its a pretty mild cam, but a step up from a stock Vortec 305/350 cam.
peace
PAuly

morepwr
06-09-2010, 01:15 PM
Whats the thoughts on lobe centers? Most of the rollers have a 112-115 lobe center. The GM performance one has a 109. Is it harder to tune with a tighter lobe center? Is one better for low end torque?

Pauly
06-09-2010, 06:38 PM
With tthe mild duration and high engine vacuum, it wouldnt be hard to tune at all. Llow LSA's and being harder to tune comes into effect moireso with more agressive durations.

peace
PAuly