How many people have the LT4 Hot cam in their cars? I have one for my new engine project but want to make sure it will be very streetable. I know it has a ton of lift at .525" with the 1.6 rockers. With AFR 190 heads that shouldn't be a problem. The duration doesn't seem too radical at 218/228 @.050. But I wanted to know from someone that actually has one in their car. What does it drive like? Does it still have decent bottom end torque? Any idling problems with puter? Any other info?

 

Are you going with a carb setup or FI?? I don't know much about carbs, but if you're going to retain the TPI style fuel injection setup don't sell yourself short on an intake. The Super ram would be the best fit for the hot cams duration on the intake side. The extra duration on the exhaust side probably isn't needed with your excellent flowing heads, but it couldn't hurt. The mini-ram would also be a good fit if you have a manual trans. I don't have any numbers but there is a lot of low-end torque that starts at around 2500 rpm and with my setup it pulls strong to 6000 rpms. I'm guessing the torque peaks at around 450 ft. lbs. at the crank. With your heads it will surely pull more on the top end.

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Blk 89 IROC-Z, mods: 355 Super ram,forged pistons, ported and polished vette heads, LT-4 hot cam, Coan 700R4 trans and 2500 stall conv., Edelbrock tes headers and intake,Performance Resource custom chip, Flowmaster catback,no cat, and all that free stuff. Best 1/4 time on stock engine was 14.6 at 94 with catback, trans, tq conv., and free mods.

 

Are you going with a carb setup or FI?? I don't know much about carbs, but if you're going to retain the TPI style fuel injection setup don't sell yourself short on an intake. The Super ram would be the best fit for the hot cams duration on the intake side. The extra duration on the exhaust side probably isn't needed with your excellent flowing heads, but it couldn't hurt. The mini-ram would also be a good fit if you have a manual trans. I don't have any numbers but there is a lot of low-end torque that starts at around 2500 rpm and with my setup it pulls strong to 6000 rpms. I'm guessing the torque peaks at around 450 ft. lbs. at the crank. With your heads it will surely pull more on the top end.

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Blk 89 IROC-Z, mods: 355 Super ram,forged pistons, ported and polished vette heads, LT-4 hot cam, Coan 700R4 trans and 2500 stall conv., Edelbrock tes headers and intake,Performance Resource custom chip, Flowmaster catback,no cat, and all that free stuff. Best 1/4 time on stock engine was 14.6 at 94 with catback, trans, tq conv., and free mods.

 

I am going to stay FI. Intake isn't set in stone yet. I am more concerned whether that cam is smooth enough for a daily driver. Even though I have 5 cars and it won't be driven every day there have been a few occasions where they all went to hell and only one ran right. Of course I was doing a major restoration on one, the other was in storage awaiting its restoration and the other 2 tore up. Leaving my with only rice to drive. My wifes 98 Maxima that we use mainly for trips.

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91 Camaro RS 5.0L Black Convertible 700R4
** Added so far **
*GM Wonderbar,Alston SFC's,spohn LCA's and Panhard rod
*Turbo City Inj Spacer
*Dual Snorkel Air Filter
*March Performance Pulleys
*GM 3.42 Gears with OEM Zexel POSI
*Edelbrock headers
*3" High Flow Cat
*3" Dynomax Exhaust
*Walbro 255 lph Fuel Pump
***getting ready for new engine. TBI version of this http://www.airflowresearch.com/Articles/A3-P1.htm

 

I run the LT4 HC. I burn my own PROMs so I have no problems with getting the engine to idle nicely as well as have good street manners. But the cam is not so large as to cause huge headaches with tuning even if you don't know how to burn PROMs. The idle on mine is fairly choppy at around 650 rpm but is definately tolerable.

I have a modified LTR setup on my car with a ported stock intake base, SLP runners ported down 1 inch, and a stock plenum that has been siamesed to match the runners. I also have a 2500 stall. My car will tear the tires up big time out of the whole and I am constantly pedalling it if I go to WOT at anything under about 30mph. So I really don't think I have any problems with a loss of low end torque....

If your main concern is driveability issues, get into PROM burning and you will be able to make it run as smoothly as you want.

Good Luck!
Laterzzzzzzz

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1987 GTA L98 MD8
355, TFS Heads, LT4 Hot Cam
My GTA

The Minnesota F-body Club

 

Is this going in your TBI car? 305 or 350? Mine idled like crap on the stock TPI chip, way too rich. It took some trial and error tuning to get it right. I wouldnt even want to attempt it on a TBI computer.

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1991 Camaro Z28
5.7L 5-Speed (originally 305)
318 RWHP, 419 RWTQ
13.23 @ 107.62 MPH (2.13 60')
Southern California
Member: SoCal F-Bodies
-=ICON Motorsports=-

 

Matt,

Did you get a cam card with the cam? If so, would you mind posting the following specs off the card?

IVO
IVC
EVO
EVC

Thanks.

------------------
Willie

Supercharged 1987 305 IROC-Z, Daily-Driver, Emissions-Legal.
Former Paxton (6-psig) with 50-hp nitrous: 12.043 @ 112.86 mph.
ATI D1SC (10-psig): 12.056 @ 116.62 mph.
All stats are altitude corrected for 3,100 feet using NHRA's Altitude Correction Table.

http://willie.camaro-firebird.org/

1987 "20th Anniversary Commemorative Edition" Z28 Convertible -- Super Chevy Show Class Winner, 1998.

 

I have purchased all the prom burning and monitoring software and have been practicing on my mostly stock motor. It is TBI and I am aware that it will probably be more difficult to get that speed density system to idle right with the reduced vacuum. Mainly concerned about the powerband of the LT4 cam being to high in the rpm range making it a great track car and a lousy street car. I like taking my convertible out with the top down for a nice cruise. I just want it to have some ***** too.

 

Unfortunately no, I did not. The cam came with itself, in a box, and that was it. No documentation at all. Yes, it made me a bit nervous too....

------------------
1987 GTA L98 MD8
355, TFS Heads, LT4 Hot Cam
My GTA

The Minnesota F-body Club

 

[QUOTE]Originally posted by Willie:
[B]Matt,

Did you get a cam card with the cam? If so, would you mind posting the following specs off the card?

IVO
IVC
EVO
EVC

Thanks.


I got a card with mine, but the only numbers it gives besides lift and duration are lobe seperation 112, and lobe centerline for intake 109, for exhaust 115, duration at .006 is 272 281, and lobe lift of .328. That is all it says.

 

sweet that is the most info I have heared on the cam so far

 

I didn't realise that this topic was so old a friend linked it to me. but when I got my cam it didn't have that much info with it. the only info it had was that it was a gm performance part cam.

 

Does anyone know how the LT4 Hot cam runs with a 305 holly carb?

 

I'm also curious if anyone has run the HOT cam with a carb setup...

 

Well, the ZZ430 engine combo that GMPP put together used the LT4 HC, so........

 

Would it be possible to run the LT4 HC with ported alluminum corvette heads? Would lift be a problem? I don't want to have to spend lots o money to run that cam. Thanks fellas. :hail:

 

i have the cam with a holley 750 and corvette aluminum heads. i had the valve guides and the plates between the springs and head surface milled .050 for clearance although in retrospect i would have milled them .080 just for security although i haven't had problems with how they are now. i also got stiffer springs that are the stock 1.25" diameter.

the only cam specs gm will give out is what's posted on gmpp's sight, apparently they're secretive about ivo, evo, etc... i emailed them a couple times about it and got nothing.

the cam is very streetable, idles just fine at 650rpm. my carb is pretty out of tune so it's not where it should be power wise right now but i think it's a good cam.

 

Here is what I came up with on the specs ...I'm not sure if they are exact though.

IVO: 1.0
IVC: 37.0
EVO: 50.0
EVC: -2.0