I was looking at the cam specs for my 1990 L98 and I was shocked to see the duration dropped by about 5 degrees for 1990. Even the lift is a tad lower but the lobe separation angle didn't change. Why'd they reduce the duration that much? Looks like just switching to a 1989 cam would be significant improvement. I'm into low end torque more than high HP numbers.

This brings us to the next question, how much power is being left on the table with the stock cam? I see people using the Crane 2032 roller cam as an upgrade to a stock motor. That's pretty much what I have as far as my motor goes, would I notice an improvement? How much? Will I need a tune since I'm using a MAP sensor and not a MAF based system. I have the N10 dual cat exhaust and a 180F thermostat right now. I notice that Crane doesn't include cars beyond 1989, I assume this is because of the MAF/MAP difference. Can I make 400ft/lbs with the Crane 2032 cam and maybe some minor porting mods to the engine? I want everything to look stock so no new runners or plenums etc, but grinding away on the inside is ok.

 

90 they switched to a flat top piston which gives more compression and the cam should have changed lsa as well. Thought it was tighter than 87-89 l98?

Either way if you did all the bolt ons with 1.6 rockers, an L98 should pick up 30-40 hp with tune. It would not be worth the effort to swap 89 cam in. It be better to use aftermarket or an lt1 cam with a matching style manifold like miniram or stealth ram.
Crane 2032 fits stock heads well and would likely be another 10-20 hp over stock cam but depends on intake manifold. Tpi will choke it off by 4500 rpm while a shorter runner manifold like miniram or stealth ram will pull to 5500. Much more hp to be made up top but you give up a peak torque number. You gain a flatter torque curve however and more top end torque which leads to better acceleration. Track times for me have show significant gains with holley stealth ram vs stock tpi in all aspects of 1/4 mile performance. It had less peak torque by alittle but much more hp and thus able to accelerate quicker

I am talkin a exhaust modded L98 with stock tpi, 2800 stall, gears and advanced timing running 13.63 at 97 mph to a 12.95 at 103.8 mph with all the top end bolt ons (hsr, pulleys, rocker arms, more tuning, and 70 lbs lighter wheels)

 

You're right I think, they tightened it up from 117* to 114.5*, so I guess that makes up for the drop in duration. I didn't know they ran dish pistons before '90, I thought they just shortened the skirt in '90 trading weight for HP. So only 10-20HP more by switching only the cam to the 2032, and I need a tune? I'm not sure that's worth the effort then unless I get say 30 ft/lbs more torque to go with it. I know I should have headers and all that, but my car is very original and I'm trying to keep it looking that way.

 

It will run ok without a tune but why go thru trouble of doing a cam and supporting mods amd not gettin it tuned? Parts have to work together and they do that by optimizing fuel and timing through the computer.

It very well could see 10-30 lb ft as well.

Again you need the intake mods to let motor breathe well. Intake is biggest restriction then it becomes heads and cam. Could squeeze power out of the stock heads with more cam so you can do that first before doing heads. Exhaust mods to exhale are necessary.

With all those done, you can get 10-30 hp more with cam swap and roughly similar torque. Depends on cam size and tune and type of intake manifold. Theres lots of combinations to consider

Dont get caught up on torque. More hp will accelerate the car faster in the end so trading some trq for hp isnt a bad thing. Just add some rear gears and converter to really have fun.


Edit: if originality is what you desire then its probably best you have someone port the stock base and maybe buy a set of large tube runners. Keep your old ones for historical purposes. Then get a custom grind cam for stock exhaust manifolds and retune for that. Really trick would be to port the stock exhaust mani's but thats very time consuming and could get pricey. Can you atleast have a 3" catback exhaust? I would think a custom grind like that and some tuning there could be 20 hp and trq. Exhaust would def hold things back