I am considering doing this instead of buying a cam, for the high milage (150000) short block. What kind of numbers are people seeing with this combo, and with what heads. Thanks Prorac1

 

Why even bother, sure maybe you'll get 10-15rwhp, but thats for $900+. You need more valve lift to make use of that ability to flow more air.

 

You're not going to see much of a return on your investment/time. People (like myself) see some nice gains with a cam and stock heads. That's got to tell you something about that stocker cam.. If it's not making the most of stock heads, throwing on some ported ones and keeping it doesn't make much sense at all IMO.

 

I looked into doing this. I think you can see some decent gains with fully ported heads, 1.6 roller rockers and a good tune. The stock heads flow pretty well, but they hit a wall at around .500" lift. Basically if you open the valve more after about .500" then you won't get any more air/fuel in.

I came up with some interesting info months ago when I was researching this, I'll see if I can dig it up when I get home today.

 

Personally, if my budget was fairly low and I wanted a decent gain, I think it's tough to beat the hotcam kit for ~$500. When you've more $ to throw into it later, those parts can be sold to recover a large portion of the initial cost as well .

 

It should work well. Gm didn't put a much bigger cam in for the lt4 just better heads and 1.6rr.

 

Ok, I found some things I had looked at previously. Since LS1's run so well stock, I looked up stats on their top ends, and compared them to the LT1 top end. I'm going to give LS1 cam specs I found as stock, and LT1 specs with 1.6 rockers, since you should do them at the same time as heads.

LS1 cam
Intake Duration @.050- 201 Exhaust Duration @.050- 212
Lift: Intake- .500" Exhaust- .500"

LT1 cam(w/ 1.6 rr's)
Intake Duration @.050- 205 Exhaust Duration @.050- 207
Lift: Intake- .477" Exhaust- .490"

As you can see on the intake side, the LT1 cam gives up about .013" of lift, but has an additional 4* of duration. Exhaust gives up .010" of lift and 5* of duration. You might add 1.7 rockers to the exhaust if you can get a hold of 8 of them. Anyway, the cams are fairly close as far as size goes, but your losing out on the exhaust side a little with the LT1 cam.

Head flow numbers, I have a note on my page here that these heads were tested on the same bench, sorry, can't remember where I got this from though.

LS1 heads, figures shown as <lift> Intake/Exhaust

.100 83/62
.200 134/103
.300 189/136
.400 222/165
.500 240/179

LT1 heads, figures shown as <lift> Intake/Exhaust

.100 72/53
.200 129/101
.300 180/136
.400 213/155
.500 214/165

You can see that the LT1 heads get outflowed throughout the whole range, but over .400" is where it gets worse. They are down only 9cfm at .300" lift, the gap is still 9cfm at .400", but at .500" the spread gets up to 26cfm. If I remember correctly, the LT1 heads leveled off at .500", meaning that at .600" they still flowed the same amount.

I think if you get a set of heads that flow in the 250-260 range on the intake side, and maybe 190ish on the exhaust side, with all the bolt ons you'll be happy. Bump the compression up a hair, get a tune and do the roller rockers and it'll put a smile on your face. Plus you'll be ready to add a cam later on if you get brave, or if you want to swap these heads onto a new motor.

 

My buddy ran 12.50 @112ish with stock cam and ported heads. 3.73 gear 6 speed. Dynoed mid/lower 300s somewhere.

 

Thank you very much for all the replys, espically to fastzintennesse, for all the research. That was kind of my thinking as well. Upgrade the heads, use my 1.6 rockers on em, and throw em on the new motor when i build it. Ive already emailed lloyd elliott about some port work, but im imagining shipping from michigan to texas and back cant be cheap, lol. But the quality of work for the price he charges is well worth the expense. Thanks again guys, prorac1

 

Id say around 40 bux for shipping...not too bad at all..


Cody

 

Im running the stock cam w ported & polished heads and intake. My best 1/4 time is 13.1 and best mph is 107. Thoes times were made w a ****y tune and my car weighs 3700+

I have 1.6 rr's too

 

Why not be patient and save up for a cam? They're only $250. Only other thing you'd need to buy for it are the gaskets and a reprogram, which you can get for another $250 altogether. So, just save up $500, save yourself the time & hassle (to do cam later will require you to remove valve covers, rockers, pushrods, and lifters , all of which were already there when you did your heads & 1.6 RR's), not to mention a good chunk of horses & torque...


P.S. You should have waited on the rockers until you have already picked up the valve springs. Now you're gonna have to uninstall everything you just worked hard to get in there. Honestly, if you haven't already replaced the heads, just hold on to your valve springs until you get your new heads. This way, you can change them out much easier, because if you do the springs while the heads are still on the motor, you have to pull out all your spark plugs (a bitch) to screw in an air hose (a bigger bitch), while you uninstall the old springs/install the new springs with a spring compressor tool (an even bigger bitch!). Trust me, I know, this is how I did it. My first time I installed them, it took me 3 days, simply because the tool we had was for single valve springs, not dual, and the whole spark plug deal, not to mention the limited space to remove/install the springs with the proper tool...

 

A buddy of mine in our car club, that posts here some did a head swap on his 95 TA. Stock cam, rockers, and valvetrain. With a stock tune on it running pig rich... he put down 310 rwhp and 335 rwhp w/ long tubes and a Flowmaster muffler. Those heads were simply a GTP Stage 1 set. Nothing more than a bowl port. He has the flow numbers, and they are alright, but nothing off the wall. I wouldn't say that it was only worth 10-15 HP. There is no substitute for good heads. A good set of flowing heads and a small cam will make more power any day over a set of crappy heads and a huge cam!!!

 

Or use the TDC method.

I honestly don't think i would have done my cam swap if i had to use the air method for swapping springs. I think it would have been absolutely necessary to pull the slp headers to get an air hose in there. That job would make me commit suicide.

-brent

 

That would be me (sorry took so long to post, but I cant post from work anymore)

Anyways, here are the flow #s from the heads I put on my car.

Lift Intake Exhaust

0.100 62.5 53.2
0.200 125.6 102.4
0.300 182.9 140.3
0.400 220.4 164.6
0.500 233.2 177.8
0.550 228.1 181.2
0.600 224.4 182.7

Like fastz was saying you can see they hit a wall aaafter .500 and start to drop. So it helps to stay under a certain lift.

Now like Chris89gta said above, they are just a bowl clean up. A good set of ported heads wouldnt hit a wall at .500.

But anyways, with that, lt headers, 1.6 rr, and no cats through the flowmaster it was actually 315 hp (I had less knock retard on that run then the 310 I had printed out) and 335 tq.

I personally think it was a good investment. Plus the springs I have on there are good enough to handle a bigger cam as well.

Just thought I would add more info.

Jason