I've decided that I'm either gonna stick the LT4 "Hot" cam or production cam in my engine. I really can't decide between 'em, so I'm asking for advice. My 305's got ported aluminum L98 heads, Torker II intake, Holley 670 TBI, 1.6 ratio roller rockers, headers, and 2.5" cat-back. It is my driver so it still has to be streetable.

-Mark W.
'88 SC Camaro w/ 305 TBI

 

Mark,
How much valve to piston,cylinder wall clearance do you have? I am going to use the same heads(acctualy ZZ3 heads but they are copys of the L98 aluminum)and was wondering how much lift I could get away with. I was going to just bolt them on an old 305 block I have when I get them back from the mchine shop, and open the valve until it hits and then measure with a dial indicator.

Zac Spalding

 

I'm not exactly sure. I wasn't aware of there being any valve to cylinder wall issues with the 1.94"/1.50" valves. I don't forsee any clearance problems with the pistons at the lift figures on either of these camshafts (since no valve is all the way open when the piston is at the top of its travel). Somebody please correct me if I'm wrong.

-Mark W.
'88 SC Camaro w/ 305 TBI

 

Mark, both of those cams will be ok for you. Obviously, the HOT cam will proabbly need some tuning on the PROM and you may have valve interference, as suggested. You will also need big springs and may have valve cap interference witht he valve seal area. you WILL need studs with those springs/lift, too or they WILL pull out sooner or later. The OEM LT4 cam is much more TBI friendly and less-head-work friendly. I think it has like 115 lobe sep... Not sure, but that is VERY EFI friendly!!! Almost too friendly. I belive that the HOT cam is liveable at 218/228 deg at .050" and should be ok with your PROM until you can tweak it for max performance...

Like to know what you decide upon. IMO, use HOT cam because the OEM LT4 is too mellow for a step-up in performance and you might wish that you just used the HOT cam later on...

 

I'm not a TBI expert, but I wouldnt stick the HOT cam in a 305 no matter what type of intake it has. Its my opinion its too big. I think the regular LT4 cam would be great for a 305 TBI, would cause the computer no problems, give a nice HP increase, and run great on the street.

------------------
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=-

 

I appreciate the opinions, keep 'em coming.
For the sake of aiding discussion...
LT4 Production
Duration @.050 : 203/210
Lift : 476/480
LSA : 115
Cost : $135.93

LT4 "Hot"
Duration @.050 : 218/228
Lift : 525/525
LSA : 112
Cost : $179.81

-Mark W.
'88 SC Camaro w/ 305 TBI

[This message has been edited by Mark305TBI (edited January 30, 2001).]

 

The hot cam is a totally different animal, it would give you more HP only above 3000rpms. How do you drive? Your idle would suck.

 

Mark, if you are looking for something soft on your but, stick with an O.E. LT4 cam. I have the LT4 hotcam in my 94. Not bad power wise, and idle is perfect for me. I have had no pcm (yes pcm for 94's and up) and wont get it until later. Although, it is not a fair comparision. I lost almost no noticable low end, but I am trying to compare a 10.5 compression engine with a 9.x one. Two different animals.

Also, you might want to look at the Crane Compucam series of camshafts if you wana nice smooth idle. I have one in my 89 and love it. Almost too tame of an idle, but darn smooth campared to the hotcam. Keep in mind, if you are moving the power band up to a higher rom, it is wise to gear your rear to match. I highly recommend you look at this as well. A cam can only do so much without the some other things that compliment it. I didn't see anything in your post about non engine related mods, and havn't look at your site yet, so forgive me if I am way off base here.

Personally, with you current stuff listed in your post, I would pick the hotcam if I had to pick between the two. You don't seem like the kind of guy that would want a poodle under the hood when you can have a pit bull, lol!

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Jerry

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89 RS Lt Blue T-Tops T5
355 Crate, Compucam 2040
Pst Front Hotchkis Rear
Edle. TES 3" Flowmaster
Harwood hood, bla, bla, bla...
94 Z28, LT1 6M, Black
Most of the bolt-ons
-------------------------

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edit: I really don't know how the lt4 hotcam would behave in a 305, but I imagine you would loose a little more low end than you would think compared to installing it in a 350. Try calling some of the manufactures hotlines and give them your mods to see what they reccommend then post them here if you feel like it.

[This message has been edited by 89RS355 (edited January 30, 2001).]

[This message has been edited by 89RS355 (edited January 30, 2001).]

 

As far as idle is concerned, I'd like it to be a little rough, but nothing too bad. I've got 3.73s in the rear and (for now, anyway) the stock torque converter. I'm in the market for a new one (maybe a Break-a-Way?) after the cam and when funds become available. I'll contact some of the cam companies and post their replies, for those who are interested...More opinions welcome.

-Mark W.
'88 SC Camaro w/ 305 TBI

[This message has been edited by Mark305TBI (edited January 30, 2001).]

 

I still think you'd like the HOT cam... The OEM LT4 really is quite mellow. If you're gonna put a high-stall and gears in it, that's just more "goodness" for the HOT cam.

 

I've decided to let you, my ThirdGen brothers, make the decision. I've set up a poll on my website (complete with graphical results) with which you can help me decide. I encourage everyone to vote, because I'm still clueless as to which one would be best.

-Mark W.
'88 SC Camaro w/ 305 TBI

 

Dont forget the lift specs on both LT4 cams are with 1.6 rockers, so they will be a little less with stock 1.5 rockers.

I am absolutely 100% certain without a doubt no questions asked that you DO NOT want the LT4 HOT cam with a 305 TBI.

 

I've got 1.6 ratio roller rocker arms.

-Mark W.
'88 SC Camaro w/ 305 TBI

 

Got a response from Jim Pace performance. It reads...

I'll leave it up for debate another week or so before I shell out the cash, but if no one can convince me otherwise I think I'm set on the production version.

-Mark W.
'88 SC Camaro w/ 305 TBI

 

Kevin, in retrospect, I am leaning towards your opinion on this. I recall stuffing a cam close to the hotcam (but crane) in a old friends tpi motor. Although this was for a Studebaker we put together one summer, it did have a 305. It was a decent cam, but a little unrully (sp?). It took alot of tuning to get it right, but was still a handful. Not something I would have wanted to drive to and from work everyday, but everyone is different. What may be too much for me, may bo too little for someone else.
Mark, after re-reading your posts, I would go with the production cam for you. Sorry to be so darn fidgety.

------------------
Jerry

-------------------------
89 RS Lt Blue T-Tops T5
355 Crate, Compucam 2040
Pst Front Hotchkis Rear
Edle. TES 3" Flowmaster
Harwood hood, bla, bla, bla...
94 Z28, LT1 6M, Black
Most of the bolt-ons
-------------------------

 

With 9 votes counted the results are 7-2 in favor of the production cam. Just an update.

-Mark W.
'88 SC Camaro w/ 305 TBI

 

Keep in mind that that a cam designed for a 350 is going to seem even larger in a smaller displacement motor.Go with production cam.To much cam sucks on the street.Actualy it wont suck enough.

 

Production is what I would use. The hotcam is too big for a 305, you'd need some better heads IMO to really make it worth while, intake and TBI too.

 

I've got better heads...got a better intake and TBI too. The only stock piece left on the top end of the motor is the cam.

-Mark W.
'88 SC Camaro w/ 305 TBI