Hey guys/gals,

Well since I have to pull my engine out to figure out what I have destroyed in the bottom end (most likely a rod bearing but who knows).. I have been kicking around the idea of a cam upgrade. Since the engine will be out what better time to do this

So my question is simple but the answer is most likely not so simple... what cam should I go with? Here is what I want to achieve..

- to run consistantly in the low-mid 13's at the most, basically to be able to run with any stock M6 LS1 F-Body at the track (best to date was 14.4's at 95 MPH... maybe some of you would say that I should be running in the 13's now maybe not, but our track is notorious for being slow)

- will not be using NOS


Here's the mods I have done which I think will influence my choice...

- Heavily ported L98 heads (these were ported a few weeks ago and I never had a chance to run my car at the track to see if I could knock off a few more 10ths)

- I have a set of Comp Cam Magnum 1.6 roller tipped rockers.

- stock valve springs.

- 2800 stall converter.

Here's the rest of the mods..

Suspension mods...

- lowered 1.5" all the way round
- SFC's
- Rear LCA Re-location brackets welded in
- solid rear lca's (UMI Performance)
- solid adj. panhard bar (UMI Performance)
- all poly urethane bushings
- KYB rear shocks

Here's the rest of the mods...

TH-700R4 Tranny completely rebuilt with all the beefy parts and a Transgo shift kit
1.6 roller tipped rockers
Flowmaster 80 Cat-Back Exhaust (no CAT and no emissions)
Hedman Headers (1 5/8" prims, 3" collectors)
TPiS Airfoil and K&N's
Modified air box/ram air
Taylor Spiro Pro 8mm Wires
Crane AFPR
Walbro 255 LPH fuel pump
Serviced and flow matched stock injectors
Derale HD Transmission Cooler
And all the free mods

My lift right now is around 440 (stock 1987 L98 cam with the 1.6 rockers) and I would like to bump it up to around 480 (so that would be a cam with a 450ish lift?)... I think that stock L98 springs should be good to around 500 or so lift, but if K-Motion springs are the way to go then I will get them...

So what's your suggestions? I have heard good and bad things about Comp Cam and Crane... any suggestions?

 

i'm not sure i can offer advice, but i think you have a flat tappet cam in an 87
i think a retro-roller would be a nice benefit
since you have a 2800 stall, you can get away with 220@50 cam easily
also you say you have a heavily ported heads, but dont know what springs you have?
i'd just find that odd that someone would heavily port heads and throw stock stuff back on, but it could come down to $$

look at the extreme cam series from CC

you have alot of goodies on the car now, i would think you need some ECM tweaking, but then again, i am totally new to EFI

 

If it is an 87 you would have a roller cam, that should be the first year they introduced them along with the intake bolt angle. I would not look at a cam in the 220 region. For a cam that big you would need a aftermarket TPI set up or a fully ported tpi setup. If you have a 350 than I would go with a 210/214 cam or a 214/219 cam. That usually works well for TPI. If you can not tune it (ecm) than stay above a 112 lca and below a 220 intake duration.

 

It came down to cash at hand when I did them.. since I wasn't replacing my cam at the time I ported my heads I never saw the need to go with new valve springs... I wasn't putting any more stress on the stock valve springs by porting my heads...

Now that I am thinking about a cam swap that will give me a .480 - .500ish lift then I am definitely going to replace the springs with a set that can handle that lift.....

I am getting close to having to do ECM tweaking, that's for sure, the stock ECM is only going to take me so far

How about this Cam from Comp Cams.... it says it works with the computer controlled" cars and specifically states for 87-98 Gen 1 350 engines. I am thinking this cam would work well with my 2800 stall torque converter, heavily ported L98 heads, and free flow exhaust... it seems to have the right RPM range for my TPI (maybe a little on the high side) of 1200-5200. The LSA is right as well 112* for my ECM

Any suggestions on this one? Good or no good?

Grind Number: CS 264H-R12
Cam Style: Hydraulic roller tappet
Basic Operating RPM Range: 1,200-5,200 RPM
Intake Duration at 050 inch Lift: 210
Exhaust Duration at 050 inch Lift: 220
Duration at 050 inch Lift: 210 int./220 exh.
Advertised Intake Duration: 264
Advertised Exhaust Duration: 274
Advertised Duration: 264 int./274 exh.
Intake Valve Lift with Factory Rocker Arm Ratio: 0.480 in.
Exhaust Valve Lift with Factory Rocker Arm Ratio: 0.480 in.
Valve Lift with Factory Rocker Arm Ratio: 0.480 int./0.480 exh. lift
Lobe Separation (degrees): 112
Intake Valve Lash: 0.000 in.
Exhaust Valve Lash: 0.000 in

 

With 1.6 rockers and that cam you would be at ~.512 lift. I think that's too much lift for stock heads....

Take a look at this cam:
Cam: Crane Powermax 2032 452/465 214(270)/220(276) 112 deg., 1800 to 5800 RPM (2000 to 5500 RPM), P/N 104224 $269.88 @ summit.
Lift (1.52 rockers): 0.458"/0.471"
Lift (1.6 rockers): 0.482"/0.496"
Duration @ 50: 214/220
LSA: 112 degrees

It may still have too much lift with 1.6 rockers.....

 

Either cam sounds good enough to meet your requirements. I would go with the one you suggested though. Reason being that the Comp cam has more radical ramp rates. Which is more beneficial. You can change valve springs and be OK. It should be OK and not hit a piston, check to be sure though.

 

I guess I should be asking the right question...

How much lift is too much lift on L98 heads? I would like to hear what others who have swapped cams and retained the stock L98 heads are running in the way of lift numbers without clearance issues....

Like is 480 too much? 500? 450? I know that 440 is OK cuz that is what my stock cam and 1.6 rockers are running now...

I have heard that .500 lift is too much for Vortec heads and at that point the valve guides need to be cut down... but what about L98 heads?

 

Do a search. There are lot's of posts on this topic.

 

Seems that from my searches I shouldn't go any bigger than .480 lift on stock heads without doing mill work...

That seem right?

 

That's what I concluded as well. It makes using 1.6 rockers with an aftermarket cam kind of senseless. On a stock cam with stock heads sure why not, but with an aftermarket cam you should do headwork or just buy new heads.

 

I ran a comp XE264HR on stock ported heads, with ported stock runners, ported plenum, stock TB, slp headers. With this set up I had great results for a mild street car. Would consistently beat stock supra turbos, car made a ton of torque, and mileage stayed arround stock.

I had to have the valve guides machined, and springs were upgraded per comps recommendation, running 1.52 rockers.

This was a good cam for my purpose.

 

I kind of figured I would need to machine the valve guides... they seem very close right now with my stock cam and 1.6 RR's.

What kind of times did you run on the 1/4 mile (if you ran it on the 1/4 mile that is)

 

I never ran the quarter in it, only on the street.

It really ran pretty well , many cars that were supposed to be faster were suprised to see my taillights.

It reved considerably better than stock but still fel flat on top, the mid range was awesome.

I now have a vortec/ hotcam set up that is considerably stronger especially on top, this is a great combo with matched parts and tuning.

The vortec would probably run well with the 264HR as well. it is a good cam- depends what you want. for a DD that hits mid thirteens and you drive everyday, can run the ARAP bin (hot factory tpi program) and get 17mpg ( I use bad california ethanol gas) this is a good way to go.

 

So is what you're telling me... run the 264HR, machine the valve guides on my ported L98 heads, and use the ARAP bin... ??

 

Yes, just remember to run a quality spring with the correct seat, and open pressures ( comp recommends a double spring) it is a fun motor for sure.

maybe mill the heads for a little more compression.

This is a vary torquey set up, Kinda like a beefed up stock powerband(stock heads, w/tpi) with more run out on top.

 

Yeah I hear ya about the springs... when I do the cam swap I will definitely get the proper valve springs.