MrJ

I'm debating doing this. The LT4 cam is only $135, and I have the TPI off of the car for porting now. I figure I am roughly halfway through a cam swap. Here are my questions.

1) How much more would I have to do to gain access to the cam? If I'm not mistaken, I'd need to pull the serpentine belt, water pump pulley, then the pump itself, then the crank pulley, then the harmonic balancer, and the timing cover... and the radiator, and move the condensor out of the way. Then I'd need to loosen the oil pan bolts, and remove the timing cover, and timing chain and gears. After that, I would have access to the cam. Did I leave anything out?

2) How much gain would I see with this cam and a ported TPI base/runners/plenum, vs the L98 cam that I have now? A few tenths? I am running a 93.5 MPH trap speed now, how much faster should I be with the LT4 cam?

3)Would this cam be OK with my 2000 stall converter and 2.73 rear end? I know the duration on the regular LT4 cam is conservative, so I don't forsee my low end suffering much, if at all.

4) Anything else I should be aware of? Will the stock valve springs hold out with the LT4 cam's lift? (something like .465/.470, I forget). thanx

oh and a disclaimer.. this IS NOT the LT4 HOT cam. It is the LT4 regular production non-HOT cam.

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91 Trans Am WS6
Bright White
5.0 TPI auto
Flowmaster 3" 2 chamber catback
Trans Go shiftkit
2000 stall converter

Built on Wednesday

Kevin91Z

iTrader: (1)

Why not get the ZZ4 cam for $100 from Scoggin Dickey? But, you'd need new valve springs so I guess thats out... The LT4 cam will be fine, the stock springs are good to .480 lift from what I've heard around here. I'd save up for some gears next.

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West Coast GM Shootout 2001!
1991 Camaro Z28
5.7L 5-Speed (originally 305)
13.25 @ 107.18 MPH
Southern California
Member: SoCal 3rd Gen F-Bodies
Webmaster: SoCal F-Bodies
-=ICON Motorsports=-

Dan87IROC-Z

I hate to be the voice of dissagreement, but while you are in there, you might as well spend some money to help your car out. Pull your heads, have new springs, retainers, and valve seals installed. Get a good timeing set like a Comp Cams or Cloytes double roller timing chain installed. I figured my LT4 Hot Cam swap is going to end up costing me $650. I do think it is going to be WELL worth the cost though!!

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1987 Chevy Camaro IROC-Z
L98 TPI 350 (5.7L)
TH 700R-4 Transmission
Borg Warner 7.75" 9 Bolt Rear End

Current Mods: LT4 Hot Cam, Comp Cams 1.52:1 Roller Rocker Arms, Edelbrock TES 1 5/8" Headers, Hooker 3" Aerochamber Cat-Back System, Performance Resource Chip, Accel Ignition Coil, Cap, Rotor, 8.8mm Wires, K&N Filters, JET TPI Air Foil, All Free Mods, Falken ZIEX Z-Rated Tires.

Best ET (w/o LT4 cam): 14.32 @ 97.7mph
(corrected for elevation)

7.5" 10 Bolt with 3.42s soon to come!

MrJ

Unfortunately, being a poor college student I don't have money to get anything installed. Everything I do will be on my own. I have debated pulling the heads and porting them, but I'm not sure how well a Dremel cuts through cast iron, and I'm also not sure how much of a pain in the a$$ it is to unbolt the exhaust manifolds and the accessories from the front of the heads. Maybe I'll just do the cam swap, we'll see. To those of you who have done it: How did you solve the problems with the timing cover? I changed the timing chain in my old V6 Camaro, and the timing cover always leaked drops of oil from then on, because it never sealed perfectly.

Dan87IROC-Z

I'm a college freashman by the way. Anyway, you really don't need to cut away a lot of metal on the heads if you port them with a dremel, all you really need to spend your time on is the area just above the valves, just use the sanding bit on your dremel and smooth out that area, not too much iron is acctually removed.

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1987 Chevy Camaro IROC-Z
L98 TPI 350 (5.7L)
TH 700R-4 Transmission
Borg Warner 7.75" 9 Bolt Rear End

Current Mods: LT4 Hot Cam, Comp Cams 1.52:1 Roller Rocker Arms, Edelbrock TES 1 5/8" Headers, Hooker 3" Aerochamber Cat-Back System, Performance Resource Chip, Accel Ignition Coil, Cap, Rotor, 8.8mm Wires, K&N Filters, JET TPI Air Foil, All Free Mods, Falken ZIEX Z-Rated Tires.

Best ET (w/o LT4 cam): 14.32 @ 97.7mph
(corrected for elevation)

7.5" 10 Bolt with 3.42s soon to come!

Ed Maher

If i'm not mistaken the LT4 cam is the same as the LT1 cam. The Lt4s used 1.6RRs though.
With that said, the Lt1 cam is basically the same as the L98 cam you have except with more lift.
IMO, don't waste your time with the swap, it won't help that much. I know 1.6RRs are more $$$, but they'll accomplish the same thing with a lot less work. If you're determined to tear into the cam, i'd at least run the comp XR 256 w/ 212/218. Should be very mild even in a 305, the @.050 #s are deceptively big due to the fast ramps on the XR series. It'll run you a little more, but get you a lot more performance. And i'd get some springs too. Unless you go over .5" lift they are pretty cheap, and worthwhile insurance.
...ed

Steve R

What are the specs on the LT4 cam?

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-80 Camaro 350, Carter AFB, headers, dual exh, ram air, all sorts of crap
-88 Iroc-Z 350tpi, 3.27 gears, 4 wheel disc, MSD 6a, tpi airfoil, k+n's, white gauges, accel coil, flowmaster, pretty quick

Dan87IROC-Z

Don't quote me, cuz I may be totally off, but I think its pretty shallow duration, like in the 210* to 215* range with a pretty good lift of like .460" to .470" or so, but again, I dunno for sure and those lift numbers maybe with a set of 1.6 rockers.

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1987 Chevy Camaro IROC-Z
L98 TPI 350 (5.7L)
TH 700R-4 Transmission
Borg Warner 7.75" 9 Bolt Rear End

Current Mods: LT4 Hot Cam, Comp Cams 1.52:1 Roller Rocker Arms, Edelbrock TES 1 5/8" Headers, Hooker 3" Aerochamber Cat-Back System, Performance Resource Chip, Accel Ignition Coil, Cap, Rotor, 8.8mm Wires, K&N Filters, JET TPI Air Foil, All Free Mods, Falken ZIEX Z-Rated Tires.

Best ET (w/o LT4 cam): 14.32 @ 97.7mph
(corrected for elevation)

7.5" 10 Bolt with 3.42s soon to come!

Todds1987iroc

I think the production LT4 cam does not have a distributor drive gear on it. This is because these motors had the distributor mounted on the front of the engine. I was told this by Jim Pace Pontiac. That is why it is so cheap. I have not seen this cam in person so I am only assuming this is true. I was thinking about using it in my engine until I found this out.

Greenshamrock77

Out of the GMPP catalog the LT4 cam is 203/210/115LS-lift=.476/.480 W/1.6 rkrs.

MrJ

Hmmm.. if that's true about it not being compatible with non-Optispark engines, than I guess the cam swap is no longer an option. Friggin roller cams cost too much, the LT4 one was the only cheap one with good specs I could find.

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91 Trans Am WS6
Bright White
5.0 TPI auto
Flowmaster 3" 2 chamber catback
Trans Go shiftkit
2000 stall converter

Built on Wednesday

JoelOl75

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[This message has been edited by JoelOl75 (edited February 10, 2001).]

Grim Reaper

I'm with Kevin, get the ZZ4. Yes, you'll need new valvesprings. But I would recommend that with any cam except a stock cam.

Do it right, do it once.

Kevin91Z

iTrader: (1)

If an LT1 cam wont fit in an older block, then explain how there is a 1994 LT1 cam bumping the pushrods in my engine right now? However, I didnt know the above about the LT4 cam.

Greg90iroc

ok i hate to be the one to contradict you guys but a freind of mine put a lt1 cam in a 92 RS with the 305 tbi. he had some good results. he runs low 15's high 14's at like 94. The lt1 and lt4 cam will work in the block. they do have a distributor drive gear. jim pace is stupid!!! what do you think drives the oil pump on an lt1 or lt4? Jimpace has out grown it's self i know that about a year ago they had 10 people employed in the parts department. It has got to be hard to keep knowlageable people employed there under those conditions. Also the lt1 cam is not going to make a diffrence. you would be lucky if you went 1 tenth faster at the track with the lt4 cam. I would go for the zz-4 cam. i have one i will sell you for 70 bucks. My palns have changed i am going to build a blown 383 here in a few months and i do not need this cam.

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90 iroc l98
last season best corected 13.62 @102
mods
full exhaust, AFPR, pulley, jet stage 1 chip, billet servo, 52mm throttle body and a few other little things.

Grim Reaper

So Greg, when are we going to start seeing you on the PROM Board? I think you would REALLY enjoy it.

MrJ

What are the specs on the ZZ4 cam? I may take you up on that offer, Greg.

Grim Reaper

208/221 112LS .487/.510 w/ 1.5s

Kevin G

LT4 Hotcam specs. 218, 228, .525 .525 112 LS
with 1.6 rockers.
The LT1, LT4, and LT4 Hotcams will all fit into older hyd. roller motors such as the L98. They all do have a dist. drive gear on them.. The LT1s use a hole for the essentrics on the front of the cam. This wont effect using them in older motors at all.





[This message has been edited by Kevin G (edited February 07, 2001).]

JoelOl75

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[This message has been edited by JoelOl75 (edited February 10, 2001).]

shawn87gta

iTrader: (1)

The LT4 production cam will work - I ran one for a while and replaced it with a Comp HR269 - 218/224, .528/.536 lift w/1.6's. On the later LT1 style cams you have to set the pin on the front of the cam in further so it doesn't interfere with your timing cover. In my opinion the LT4 production cam is junk. You would be disappointed after doing all the work. If you want to try it I have one in my garage I'll give you, it only has about 10k miles on it. My car runs immensely better with the Comp cam, and I'm only running 1.5 rockers now so I wouldn't have to change the springs. The Comp cam was the only mod done at the time, other than changing back to 1.5's (I was running 1.6's with the LT4 prod. cam). The other mod's in my sig were done at the same time I originally installed the LT4 cam. If you change cams, definitely upgrade the pushrods - I found bent ones with both cams, and went with Trick Flows - $80 at Summit.

Hope this helps,
Shawn

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87 GTA, auto w/2075 stall, 3.27 rear, L98 .020 over,Comp 269HR cam & 1.5 roller tips, ported heads w/3 angle vj & brnz guides, 52mm TB & airfoil, SLP runners, ported plenum, ported intake, Edelbrock TES, AFPR, MSD 6A/Blaster coil, MAF screens, cold-air induction, vortec muffler, heated O2, Ed Wright Fastchip.

Greenshamrock77

an addition to the earlier subject of porting with a dremel. I did it, I had a set of 041 gm castings laying around and I started asking how to properly port. I found that the dremel grinding stones worked best. The ones that are either pink or grey and are about a 1/2" sphere in shape. The sander drums worked good on the exhausts, but they wear out fast. I own an 82' Camaro w/ the damn electronic Q-jet. The motor is an fresh 327 w/ flat tops and it has the 216/228/112LS flat tappet cam (emmissions legal) in it. I made sure EVERY smog component was hooked up. Did the heads help? Well I have run dead even with a 2001 corvette to 150MPH, which is where he let off! You be the judge. I've done it 3 times, I see the guy on the way home sometimes. The car has 3.73 gears and I swapped a world class T-5 in it. The motor does not have much below 4200RPM, but its like the space shuttle all the way from 4200 to 6000. I am going to hit up a guy down the street with a 93' Viper RT/10. I'm sure he'll beat me, but he won't lose me. I'm curious how I'll do!

Greg90iroc

You will see me on the prom board here pretty soon. I have to get some money for the engine and prom burning equipment. I graduate collage next december. That is when the 383 will be built. I hope to run some AFR 195's with a zz-9 cam or posibly a custom grind similar to the zz-9 with posibly more concentration on exhaust. it is going to also have a super ram upper intake with a 12# ati. You know I have to keep my first blown engine mild right. I have to upgrade the chassis too. Right now I am only going to spend $200 per semester on mods. I just bout some 1.6 roller rockers. I hope they help power but if they do not I will be happy because of the decrease in wear on the valve guides. The specs on the zz-4 cam are 208 intake and 221 exhaust .474 intake lift and .510 exhaust lift with 1.5 rockers.

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90 iroc l98
last season best corected 13.62 @102
mods
full exhaust, AFPR, pulley, jet stage 1 chip, billet servo, 52mm throttle body and a few other little things.

blak92!

Sometimes I dont know where people get their facts, and its funny how insistant people can be. Let me clear this up.

ALL LT1/LT4 cams WILL FIT in any hydralic roller block Gen I engines. THe only difference with the 1995 and 1996 LT1 camshafts(including the LT4 cam) is the dowel pin on the cam. 95 and up used a longer dowel pin on the cam to drive the water pump unit which was revised from the earlier GEAR driven water pumps from 92-94. And if somebody argues this, I will personally take the cam that I took out of my 95 vette and JAM it up their ****, so they can feel the larger pin, and its compatibility with the older blocks.


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'92 Z28 Black 5.7L 5 Speed
'95 Competition Yellow Corvette Coupe 6 Speed

[This message has been edited by blak92! (edited February 09, 2001).]

Greg90iroc

there is another diffrence or so i have heard that the lt4 and lt1 cam does not have the fuel pump eccentric. This means you have to use an electric fuel pump if you have a carb. This not that big of a deal electric fuel pumps are better any way. At any rate the fuel pump eccentric is irrelivant to most of us any way.

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90 iroc l98
last season best corected 13.62 @102
mods
full exhaust, AFPR, pulley, jet stage 1 chip, billet servo, 52mm throttle body and a few other little things.

91banditt2

iTrader: (1)

what are the specs for the ZZ4 cam with 1.6RR

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1991 banditt2 firebird #130of#600

Grim Reaper

91bandit, take the lift that I gave for ZZ4 and multiply it by 1.6 and then divide by 1.5. I'll let you do the math.

Dyno Don

iTrader: (7)

MrJ:
Back to your list of getting at the cam,
(1)You also must remove the valve covers, loosen the rockers,remove the push rods, lifter guide plates and lifters. Just thought I'd mention it if you forgot.

Don>>>

Beefy89

First of all,if you port the heads,fully port them or you'll just be wasting your time.Start out with a carbide cutter and then go with a stone or sand paper rolls.There is alot of iron that can be removed from the stock heads.As far as the cam goes,I installed an LT1 cam and 1.6 roller tips last fall in my L98 when I rebuilt it.The dowel pin on the LT1 cam sticks out about .300" longer than the pin on the L98 cam.Tap it into the cam as far as it will go and grind the rest off till you reach the desired length of .300"or so.I can only speak from experience,but my GTA runs a hell of alot better with the LT1 cam than it did with the stock L98 cam.The LT1 and LT4 cams are pretty mild,but with 1.6 rockers you'll be about .489" lift.I drive it daily in the summer months and also live 25 miles from work so I wanted to keep the MPG decent,but still get some performance out of it.

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We need Perry Mason