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LT4 Hotcam in 97 Vortec 350 Help

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Old Mar 19, 2009 | 11:10 AM
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Engine: 97 5.7 Vortec LT4 hotcam
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LT4 Hotcam in 97 Vortec 350 Help

I am fixing to put a hotcam into the 97 vortec 350 (carb) in my 88 camaro. I have the valve lift problem fixed. But since this is my first roller motor I have worked on, I have a few questions.

1) Since this cam is regularly used for the LT style engines, does anything need to be changed for it to work? More specifically, will a regular timing set for the 97 motor work?

2) Is http://store.summitracing.com/partde...2D1157&FROM=MG the correct timing chain?

3) With the hotcam will I need to swap the distributor drive gear?

4) If so, what is the right size shaft for a GM HEI?

5) Do I need to buy a new cam button? they simple push into the end of the cam gear and press against the timing cover right?

Thanks for all the help.
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Old Mar 19, 2009 | 11:23 AM
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Re: LT4 Hotcam in 97 Vortec 350 Help

1) the front of the cam takes 3 bolts and has a pin. For LTx engines, the pin had to be extra long. If you find it so, push it in until it's about 1/4". If it won't push, get a hacksaw. 2) Looks to me like the correct timing set3) depends on your distributor. If it came from an '87-up third gen, you can use it as is. Otherwise, you'll need the gear.4) AFAIK the .491" shaft is a GM, while the .500" is aftermarket distributors. The .491" gear can be enlarged to .500", but no way to shrink the .500 gear to .491".5) You don't need a button at all, just use the stock plate. 6) enjoy the monster torque from 2600 to 5600 rpm!
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Old Mar 19, 2009 | 12:05 PM
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Car: 1987 IROC
Engine: 350 vortec
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Re: LT4 Hotcam in 97 Vortec 350 Help

thats a great combo with an RPM or air gap intake or something similar, real blast to drive. and no you won't need a thrust button. the front cover however is supposed to be replaced if its the stocker because the gasket is really just a bead of silicone around the backside
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Old Mar 19, 2009 | 12:45 PM
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From: Lincolnton, NC
Car: 88 IROC
Engine: 97 5.7 Vortec LT4 hotcam
Transmission: 700 r4
Axle/Gears: 3.73
Re: LT4 Hotcam in 97 Vortec 350 Help

Originally Posted by brandoz28
thats a great combo with an RPM or air gap intake or something similar, real blast to drive. and no you won't need a thrust button. the front cover however is supposed to be replaced if its the stocker because the gasket is really just a bead of silicone around the backside
are you talking about the timing chain cover? Would any sbc work or does it have to be specific for a roller?
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Old Mar 19, 2009 | 07:02 PM
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Re: LT4 Hotcam in 97 Vortec 350 Help

Originally Posted by brandoz28
thats a great combo with an RPM or air gap intake or something similar, real blast to drive. and no you won't need a thrust button. the front cover however is supposed to be replaced if its the stocker because the gasket is really just a bead of silicone around the backside
Why would you replace the whole timing cover? Just clean the mating surface, put on a new gasket or sealer, and put it on...?
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Old Mar 19, 2009 | 11:15 PM
  #6  
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From: Iowa
Car: 1987 IROC
Engine: 350 vortec
Transmission: TH350 3500 stall
Axle/Gears: 3.73 10 bolt grenade
Re: LT4 Hotcam in 97 Vortec 350 Help

its a plastic cover if it's a stocker, and even with fresh silicone its prone to leakage. you'd have to check with a standard cover, i've never actually used one on a vortec motor, there's a reluctor ring on them for the crank sensor, and i'm not sure if the balancer snout is shorter on those than an older small block, but you may want to check. i guess what i'm saying is i'm not sure if that reluctor will clear a standard cover, and if its removed you may need a new balancer or turn down the ring to fit.
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Old Mar 21, 2009 | 09:02 AM
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Car: 88 IROC
Engine: 97 5.7 Vortec LT4 hotcam
Transmission: 700 r4
Axle/Gears: 3.73
Re: LT4 Hotcam in 97 Vortec 350 Help

Thanks for all of the help. Ordered everything last night. Was hoping to get it in next weekend, but my springs are on backorder until April 4. Cant wait to see how it turns out.
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Old Mar 21, 2009 | 09:07 AM
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From: Iowa
Car: 1987 IROC
Engine: 350 vortec
Transmission: TH350 3500 stall
Axle/Gears: 3.73 10 bolt grenade
Re: LT4 Hotcam in 97 Vortec 350 Help

you can use the comp 982 kit with that cam and it works pretty well. what springs were you gonna use?
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Old Mar 22, 2009 | 01:10 AM
  #9  
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Engine: 92 5.7 tpi 5.3
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Re: LT4 Hotcam in 97 Vortec 350 Help

i put a remaned vortec bottom end into a 89 suburban last year.
the short block didn't come with the reluctor.
the timing cover and balancer from the old TBI motor fit with no problems other than i needed to drill and tap 2 bolt holes for the timing cover.
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Old Mar 22, 2009 | 10:08 AM
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Re: LT4 Hotcam in 97 Vortec 350 Help

Originally Posted by DENN_SHAH
i put a remaned vortec bottom end into a 89 suburban last year.
the short block didn't come with the reluctor.
the timing cover and balancer from the old TBI motor fit with no problems other than i needed to drill and tap 2 bolt holes for the timing cover.
If you were to compare the TBI and Vortec balancers, you would find that the Vortec balancer is slightly thinner to accomodate the extra thickness of the crank reluctor wheel.

peace
Hog
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Old Mar 22, 2009 | 06:44 PM
  #11  
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From: Lincolnton, NC
Car: 88 IROC
Engine: 97 5.7 Vortec LT4 hotcam
Transmission: 700 r4
Axle/Gears: 3.73
Re: LT4 Hotcam in 97 Vortec 350 Help

Originally Posted by brandoz28
you can use the comp 982 kit with that cam and it works pretty well. what springs were you gonna use?
I am using GM ls6 springs with some comp retainers and different seals.
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Old Mar 24, 2009 | 11:00 AM
  #12  
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From: Iowa
Car: 1987 IROC
Engine: 350 vortec
Transmission: TH350 3500 stall
Axle/Gears: 3.73 10 bolt grenade
Re: LT4 Hotcam in 97 Vortec 350 Help

got the part numbers for the comp pieces?
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Old Mar 24, 2009 | 11:41 AM
  #13  
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From: Lincolnton, NC
Car: 88 IROC
Engine: 97 5.7 Vortec LT4 hotcam
Transmission: 700 r4
Axle/Gears: 3.73
Re: LT4 Hotcam in 97 Vortec 350 Help

The GM PART # 12499224 is the LS6 beehive valve spring set. The retainers needed are the COMP Cams 787-16. This with the stock valve seals will allow 0.500 lift. If you change the valve seals, you can get 0.550. The seals that will work are SEALED POWER Part # ST2015. Yes these valve seals are for a dodge, but work. This came from a guy that does a lot of work on vortec engines. I will be starting out just using the stock 1.5 rockers and upgrading down the road to some 1.6 roller rockers. Just dont have the funding right now.

Last edited by 3rdgenmaro; Mar 24, 2009 at 11:48 AM.
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Old Mar 24, 2009 | 01:37 PM
  #14  
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From: Iowa
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Engine: 350 vortec
Transmission: TH350 3500 stall
Axle/Gears: 3.73 10 bolt grenade
Re: LT4 Hotcam in 97 Vortec 350 Help

i guess i don't know what you paid for those springs but the complete comp 982 kit is like 120 through summit, thats what i use just search 982 kit on their site and you'll see it
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Old Mar 24, 2009 | 01:40 PM
  #15  
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From: Lincolnton, NC
Car: 88 IROC
Engine: 97 5.7 Vortec LT4 hotcam
Transmission: 700 r4
Axle/Gears: 3.73
Re: LT4 Hotcam in 97 Vortec 350 Help

you can get them through any GM Performance parts dealership or from Scoggin-Dickey for $56. In the long run I ended up saving around $15 going this route.

Dont you have to machine them for the springs you are talking about?
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Old Mar 24, 2009 | 08:58 PM
  #16  
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Re: LT4 Hotcam in 97 Vortec 350 Help

nope, they went right in. i work at a GM dealer so i know where to get the springs, it was the retainers and locks that i was moreso interested in. these springs will give you flexibility to go to .550 lift by just throwing them on
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Old Mar 25, 2009 | 08:14 AM
  #17  
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From: Lincolnton, NC
Car: 88 IROC
Engine: 97 5.7 Vortec LT4 hotcam
Transmission: 700 r4
Axle/Gears: 3.73
Re: LT4 Hotcam in 97 Vortec 350 Help

I was under the impression that you could not go past .500 without changing the valve seals.
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Old Mar 25, 2009 | 10:24 PM
  #18  
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From: Iowa
Car: 1987 IROC
Engine: 350 vortec
Transmission: TH350 3500 stall
Axle/Gears: 3.73 10 bolt grenade
Re: LT4 Hotcam in 97 Vortec 350 Help

our machine shop said they're good to .550 with the springs...
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Old Mar 27, 2009 | 02:20 PM
  #19  
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From: Lincolnton, NC
Car: 88 IROC
Engine: 97 5.7 Vortec LT4 hotcam
Transmission: 700 r4
Axle/Gears: 3.73
Re: LT4 Hotcam in 97 Vortec 350 Help

I dont really know. I am just going off of what I was told by someone that works on Vortecs alot. They might be fine without changing seals, but Im going to. Better safe then sorry.
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Old Mar 27, 2009 | 03:54 PM
  #20  
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Car: 1987 IROC
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Transmission: TH350 3500 stall
Axle/Gears: 3.73 10 bolt grenade
Re: LT4 Hotcam in 97 Vortec 350 Help

i agree, better safe than sorry, not trying to bully around, just letting you know what my prior experience is
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Old Mar 27, 2009 | 07:53 PM
  #21  
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From: Lincolnton, NC
Car: 88 IROC
Engine: 97 5.7 Vortec LT4 hotcam
Transmission: 700 r4
Axle/Gears: 3.73
Re: LT4 Hotcam in 97 Vortec 350 Help

oh I appreciate the help. Always good to have more than one person's oppinons. Maybe if I feel up to it, I might try to install everything tomorrow. Ive been fighting the flu so who knows. Just have to wait and see. If not, I might have to wait a week or two to get it put in.
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Old Apr 6, 2009 | 09:03 AM
  #22  
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Car: 88 IROC
Engine: 97 5.7 Vortec LT4 hotcam
Transmission: 700 r4
Axle/Gears: 3.73
Re: LT4 Hotcam in 97 Vortec 350 Help

As an update, I got the cam and valve springs swapped out over the past couple weekends. Im ordering a new replacement GM timing cover with gaskets from Summit $23. Advance wanted $48. Once that comes in, I can button up the front, set my valves and be ready to fire up.
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Old Apr 6, 2009 | 09:11 AM
  #23  
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From: Iowa
Car: 1987 IROC
Engine: 350 vortec
Transmission: TH350 3500 stall
Axle/Gears: 3.73 10 bolt grenade
Re: LT4 Hotcam in 97 Vortec 350 Help

you're really gonna like it when you get it dialed in, really good torque and enough horsepower to keep you happy for a while
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Old Apr 8, 2009 | 10:28 AM
  #24  
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From: Lincolnton, NC
Car: 88 IROC
Engine: 97 5.7 Vortec LT4 hotcam
Transmission: 700 r4
Axle/Gears: 3.73
Re: LT4 Hotcam in 97 Vortec 350 Help

That sounds great!

Just checked my tracking number through summit and the timing cover will be in tomorrow. So that means hopefully friday night she will be running! I need to remember to take some pics while I have almost everything apart.
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Old Apr 9, 2009 | 02:09 PM
  #25  
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From: Iowa
Car: 1987 IROC
Engine: 350 vortec
Transmission: TH350 3500 stall
Axle/Gears: 3.73 10 bolt grenade
Re: LT4 Hotcam in 97 Vortec 350 Help

i'll let you know how it does with a 150 shot of juice, i'll be throwing the same cam in my junk soon. should be a blast with my 3100-3150 raceweight
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Old Apr 9, 2009 | 04:44 PM
  #26  
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From: Lincolnton, NC
Car: 88 IROC
Engine: 97 5.7 Vortec LT4 hotcam
Transmission: 700 r4
Axle/Gears: 3.73
Re: LT4 Hotcam in 97 Vortec 350 Help

sounds good! The main problem for me right now is my open 3.42 diff. I have a 94 disk brake posi rear in line to get, but the guy wants to keep it in his car (was rolled) so he can move it around the shop until he parts it out completely. Im going to try to talk to him this week and see if he has an idea of when he will pull it. I might try to pick one up somewhere else though if it is going to be awhile. He only wants $125 for it, so it is hard to pass up, but hard to wait on.
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Old Apr 9, 2009 | 05:52 PM
  #27  
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From: Iowa
Car: 1987 IROC
Engine: 350 vortec
Transmission: TH350 3500 stall
Axle/Gears: 3.73 10 bolt grenade
Re: LT4 Hotcam in 97 Vortec 350 Help

with a stock slipping 700r4, open 3.42s with regular street tires. and a 180 pound passenger in a full weight car went about 8.7 in the eighth. this was with the hotcam, same car, with some drag radials, posi with 3.73, pro built trans with a 3000 PI converter went 8.2x-8.3x reliably. what intake you gonna use? this motor REALLY liked the edelbrock RPM. air gap would rock if you've got the hood clearance
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Old Apr 9, 2009 | 07:18 PM
  #28  
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Car: 86 Camaro IROC-Z
Engine: 305 TPI (retrofit)
Transmission: T5
Axle/Gears: Crappy stock 10-bolt gears
Re: LT4 Hotcam in 97 Vortec 350 Help

The lift increase delivered by beehive style springs is an awesome advantage for Vortecs, here in Calgary machining costs an arm and a leg. Unfortunately the comp beehives (aka: 26918-16) are prohibitive expensive. Imagine my delight when i discovered the GMPP LS6 Springs ($75). My only concern in this posters case is that the reccomended springs for comps equivalent to the GMPP LT4 HOT Cam (268XFI) have a seat pressure of 130lbs (1.800 installed height) while the GMPP LS6 springs only provide 90lbs of seat pressure (again at 1.800 installed height).

Has anyone experienced problems?

-Zander
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Old Apr 12, 2009 | 07:21 PM
  #29  
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From: Lincolnton, NC
Car: 88 IROC
Engine: 97 5.7 Vortec LT4 hotcam
Transmission: 700 r4
Axle/Gears: 3.73
Re: LT4 Hotcam in 97 Vortec 350 Help

Well, I got it fired up this weekend. Idle didnt really change alot. I still have some work to do. I drove it and at first I couldnt tell much difference. I can tell some more top end pull around 5k rpms. But I think my problem is in my throttle cable setup. Im almost certain that Im not getting full throttle the way it is now. And I know my TV cable is too tight. So hopefully next weekend I can get that straightened out. Once I solve that I will work on dialing in the timing and the vac springs on my holley 600.

Oh and Im running a stock bottom end, headers, and an Edelbrock Performer RPM. It was already on the motor so I didnt see the need right now to upgrade to the air-gap.
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Old Apr 20, 2009 | 10:30 AM
  #30  
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From: Lincolnton, NC
Car: 88 IROC
Engine: 97 5.7 Vortec LT4 hotcam
Transmission: 700 r4
Axle/Gears: 3.73
Re: LT4 Hotcam in 97 Vortec 350 Help

Well I got the throttle fixed. It definately wasnt opening all the way. BIG difference driving it now. It really opened the car up. I adjusted the TV cable some, alittle too loose now, but I can fix that next weekend. Still havent been able to play much with the timing or carb. I run it some this weekend and now I have a nasty little noise in the rearend somewhere. I think it is a U-joint going out. Got to fix that before I try to drive it anymore.

so how has yours been going?
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