Vortec CT350 crate in a street car.

General engine tech -- Drag Racing to Circle Track

Moderator: Team

ClassicRob
Member
Member
Posts: 117
Joined: Thu Apr 22, 2021 3:40 pm
Location: Georgetown, Texas

Re: Vortec CT350 crate in a street car.

Post by ClassicRob »

BillK wrote: Tue Jun 29, 2021 8:41 am To be honest with looking at the specs in the GMPP catalog I would put it in just like it is. With the 3.73 gears it will probably be more than you will ever need. Save the money for your traditional build :)

Just my opinion,
Bar gets quiet - slight pause. Everyone starts laughing!

Seriously, I have thought about that, and youre probably right.
Elroy
Pro
Pro
Posts: 288
Joined: Tue Jul 16, 2019 12:46 pm
Location:

Re: Vortec CT350 crate in a street car.

Post by Elroy »

The 787 Comp retainers will clear nearly .600 lift on a stock vortec give or take when installed at 1.800 or so. Depending on this and that.
User avatar
BOOT
Guru
Guru
Posts: 2895
Joined: Fri Apr 09, 2010 6:23 pm
Location: Michigan

Re: Vortec CT350 crate in a street car.

Post by BOOT »

I just wanna point out some the GM blue LS springs I've used, if you shim them to 120 seat they may be real close to coil bind depending on your cam.

As F-BIRD said there really isn't roller springs, just springs that fit your use.
Channel About My diy Projects & Reviews https://www.youtube.com/c/BOOTdiy

I know as much as I can learn and try to keep an open mind to anything!

If I didn't overthink stuff I wouldn't be on speedtalk!
F-BIRD'88
Guru
Guru
Posts: 9802
Joined: Tue Mar 27, 2007 6:56 pm
Location: Ontario, Canada

Re: Vortec CT350 crate in a street car.

Post by F-BIRD'88 »

The spring pressure at stock seat installed height for that spring is only 90 psi @ 1.80". Open height spec is 295 @ 1.25". spring rate is 375 LBS per inch.

You want to shim the spring installed height to about 120 lbs @seat..

It is just right for both the Isky Z27 and the Isky hyd 201278. when installed correctly..
It is not a "roller spring"..

But it does work very well on mild to moderate hyd roller sbc cams too.
Install @ 1.72". seat pressure 120#. open pressure 304 #

net lift on the Isky (.507" lift gross) cam is only .491" with lash set..
It does not get any where near coil bind .which is 1.085" according to gmpp.

just right. gmpp #12499224

GM now uses these LS6 beehive springs on all their CT crate motors with vortec heads.
F-BIRD'88
Guru
Guru
Posts: 9802
Joined: Tue Mar 27, 2007 6:56 pm
Location: Ontario, Canada

Re: Vortec CT350 crate in a street car.

Post by F-BIRD'88 »

Its the oem stock vortec rocker arms that may need attention.
Check rocker stud to rocker slot clearance at full lift.
Needs .030" clear.. You can make the rocker slot a little longer by grinding it a bit.. (If needed)
Longer not wider. It ,if any ,will only need minor tweeking with the Isky Z/27 solid cam..
Not that hard. It will GLH. →→→

Remember with the guided style rockers use a round wire feeler guage to set valve lash (.016")

Elgin sells stock type sbc guided style rocker with a long slot also
F-BIRD'88
Guru
Guru
Posts: 9802
Joined: Tue Mar 27, 2007 6:56 pm
Location: Ontario, Canada

Re: Vortec CT350 crate in a street car.

Post by F-BIRD'88 »

Alternative.... This ct350 should be a factory oem " Roller block"
Which means it will accept all the OEM hyd roller valvetrain, lifters spyder + dog bones and a oem style sbc hyd roller cam.

Eg Melling cam #22280. 283/287 220/224@.050" .495/.502. 110 lsa 107/113
(I would install it at 104 in cl)
110 lsa (104/116)

Use the same gmpp LS6 springs + comp retainers.
Same 120# installed seat pressure.
Bolt in and go.. It will make very good power and torque.
Needs long slot guided rockers.
User avatar
CamKing
Guru
Guru
Posts: 10709
Joined: Wed Aug 08, 2007 4:05 pm
Location: Denver, NC
Contact:

Re: Vortec CT350 crate in a street car.

Post by CamKing »

Here's what I recommended.

Cam# SBC, H70330-71330-110
224/228 @.050"
.330"/.330" Lobe Lift
.495"/.495" Valve Lift
110 LSA

Lifter# J842H
.842" Hydr F.T. lifter set

Spring# JRC05
1.250" Single Spring w/Damper
115# @ 1.700", C.B. 1.120"
Mike Jones
Jones Cam Designs

Denver, NC
jonescams@bellsouth.net
http://www.jonescams.com
Jones Cam Designs' HotPass Vendors Forum: viewforum.php?f=44
(704)489-2449
User avatar
BOOT
Guru
Guru
Posts: 2895
Joined: Fri Apr 09, 2010 6:23 pm
Location: Michigan

Re: Vortec CT350 crate in a street car.

Post by BOOT »

F-BIRD'88 wrote: Tue Jun 29, 2021 1:54 pm It does not get any where near coil bind .which is 1.085" according to gmpp.
Set I actually checked the coil bind was less, .480 lift and if I went 1.72 it would have been too close to coil bind. I was at 1.75 according to my notes and it was just a little over .080 from coil bind if I rem right. So -0.030 & -0.020 your 0.030 from coil bind on the springs I used.
Channel About My diy Projects & Reviews https://www.youtube.com/c/BOOTdiy

I know as much as I can learn and try to keep an open mind to anything!

If I didn't overthink stuff I wouldn't be on speedtalk!
User avatar
BOOT
Guru
Guru
Posts: 2895
Joined: Fri Apr 09, 2010 6:23 pm
Location: Michigan

Re: Vortec CT350 crate in a street car.

Post by BOOT »

Here's a link to where they say the coil bind is 1.200 https://www.summitracing.com/parts/nal-12499224

Not the first time specs are wrong as many know from real world experience and why you should double check. I did because I found multiple diff coil bind specs for those springs at the time I was setting up the heads. When in doubt, pull your mic out! :lol:
Channel About My diy Projects & Reviews https://www.youtube.com/c/BOOTdiy

I know as much as I can learn and try to keep an open mind to anything!

If I didn't overthink stuff I wouldn't be on speedtalk!
F-BIRD'88
Guru
Guru
Posts: 9802
Joined: Tue Mar 27, 2007 6:56 pm
Location: Ontario, Canada

Re: Vortec CT350 crate in a street car.

Post by F-BIRD'88 »

Latest GMPP part number is now 19420455
Same spring design and purpose apparently new supplier.. Even if the coil bid height is 1.20"
You can then shim for a slightly higher 1.725 to 1.730" installed
height and get plenty seat and open pressure with all the cams I mentioned.
User avatar
BOOT
Guru
Guru
Posts: 2895
Joined: Fri Apr 09, 2010 6:23 pm
Location: Michigan

Re: Vortec CT350 crate in a street car.

Post by BOOT »

1.725 - .495 = 1.23 I used Camking's specs IF used with GM LS Blue springs
1.23 -1.20 = 0.030

What's you min from coil bind? I've read .080 to .050 min


FYI I haven't checked the new part number that aren't painted blue But there are still blue springs out there by the 12499224 part number mentioned in one of your earlier post. I'm not trying to be a jerk, I just don't want someone to have an issue from what I've noticed with the Blue springs IF they shim them down.
Channel About My diy Projects & Reviews https://www.youtube.com/c/BOOTdiy

I know as much as I can learn and try to keep an open mind to anything!

If I didn't overthink stuff I wouldn't be on speedtalk!
KnightEngines
Guru
Guru
Posts: 2682
Joined: Fri Jan 09, 2009 8:51 pm
Location: Australia

Re: Vortec CT350 crate in a street car.

Post by KnightEngines »

CamKing wrote: Tue Jun 29, 2021 3:22 pm Here's what I recommended.

Cam# SBC, H70330-71330-110
224/228 @.050"
.330"/.330" Lobe Lift
.495"/.495" Valve Lift
110 LSA

Lifter# J842H
.842" Hydr F.T. lifter set

Spring# JRC05
1.250" Single Spring w/Damper
115# @ 1.700", C.B. 1.120"
That's a nice cam for that motor.
You wouldn't close up the lsa to 108? - I would, but sometimes I'm stupid.
F-BIRD'88
Guru
Guru
Posts: 9802
Joined: Tue Mar 27, 2007 6:56 pm
Location: Ontario, Canada

Re: Vortec CT350 crate in a street car.

Post by F-BIRD'88 »

Cam King is usually right on the money with stuff.
User avatar
CamKing
Guru
Guru
Posts: 10709
Joined: Wed Aug 08, 2007 4:05 pm
Location: Denver, NC
Contact:

Re: Vortec CT350 crate in a street car.

Post by CamKing »

KnightEngines wrote: Tue Jun 29, 2021 9:21 pm
You wouldn't close up the lsa to 108?
The 110 LSA is for vacuum purposes.
Mike Jones
Jones Cam Designs

Denver, NC
jonescams@bellsouth.net
http://www.jonescams.com
Jones Cam Designs' HotPass Vendors Forum: viewforum.php?f=44
(704)489-2449
User avatar
BOOT
Guru
Guru
Posts: 2895
Joined: Fri Apr 09, 2010 6:23 pm
Location: Michigan

Re: Vortec CT350 crate in a street car.

Post by BOOT »

CamKing wrote: Wed Jun 30, 2021 10:41 am
KnightEngines wrote: Tue Jun 29, 2021 9:21 pm
You wouldn't close up the lsa to 108?
The 110 LSA is for vacuum purposes.
That explains comp always using 110
Channel About My diy Projects & Reviews https://www.youtube.com/c/BOOTdiy

I know as much as I can learn and try to keep an open mind to anything!

If I didn't overthink stuff I wouldn't be on speedtalk!
Post Reply