Ok so I have a 87 l98 block im building, .30 over, eagle 383 stroker rotating Assembly, l98 cast heads , edelbrock RPM airgap intake, and a Demon 750.

I want a prity radical/good lope. Has to be Hydraulic lift and and flat tappet. (or should i go full roller)?

Im looking to get most likely a comp. maybe magnum? or extream energy.

PLEASE post your input on a good cam. It doesn't need to be a really street-able cam.

 

The tighter the lobe seperation is the more radical it will be. Normally a 110 is pretty decent all around. Also remember the more duration you have the more compression you will lose. So I would say nothing more than a 290 advertised duration or 230 @ .050. I would go roller if it was my choice in fact that is what I am doing after I just wiped out a flat tappet in less than 100 miles and 3 hours run time. The thing you have to keep in mind is that you will have to put an aditive in your oil everytime you change your oil with a flat tappet to get you cam to last for a long period of time. You can do a google search for zinc in oil and it will explain it better than I can.

 

Yeah Shell Rotella T is a good oil with zinc. id be using that. And i was thinking the Comp Cam Magnum 280H Hydraulic Flat Tappet, lift .480'' Duraration 280° RPM range 2000-6000 and has a lobe separation of 110. and 230° Intake / 230° Exhaust at .050. does seem like a perfect cam.

any opinions on this cam?

 

Even the Rotella T doesn't have enough zinc in it anymore. That is a pretty decent cam. It would be a good cam all around.

 

Really then whats left?

 

Mobil 1 15W-50 racing synthetic, Valvoline VR1, Royal Purple full syn. 10W-30, Pennzoil 20W-50 racing, CHEVRON DELO 400 LE 15W-40, VALVOLINE NSL/NOT STREET LEGAL 20W-50 (ORDER FROM NAPA/SUMMITT/JEGS), and Redline just to name some. Granted there are probably more that I have missed. I have used and like the Valvoline VR1 and it runs about $4 a quart.

Dave

 

I would agree with all of those.

 

What is your C.R.? What rpm stall converter do you have?

 

I ran the Magnum 280H.
Great cam I must say.
Aggresive enough, but still idled pretty good. I was happy with it.

In fact, when I upgraded to a roller, I used the roller version of that cam.

 

Have the guide bosses been machined to accept higher lift?

 

well depends if I go with -12cc flat toppers or -5cc flat toppers. What should i do?

most likely -12cc.
and iron l98 heads are 64cc so 9.9 cr or should i go to 10.7?

and I dont got a stall yet most likely like a 2,800-3,000

got a vid?

no

 

Without machine work, you're limited to about .480" of lift or so, probably a touch less.

 

Yeah if I use these heads I will be getting them all machined out for bigger valves and etc.

Or I will be something like the Edelbrock E-tec heads.

 

The heads will really be holding you back. They are great when ported and open up nicely in the right areas. But in cast form they are just another set of stock heads. They flow like mad with full porting and 2.02in 1.6ex from what i have read. There's a nice thread on just that if you use the search function.

I ported a set of L98 iron heads and like i said they have plenty of meat in the right places. But i found that the casting is very thin at the base of the intake bowls behind the valve guide boss (got a picture of what I'm talking about if any is interested).

If you just go with the bigger valves and no porting you will probably want a cam with a long duration to keep the valves open as long as possible. Someone correct me if I'm wrong on this.

 

Yeah Id like a picture, and what kind of duraration would you recommed then? I would most likely port/or have then ported.

 

heres a photo of where i broke through on these 083 casting heads.



heres the link to the thread about porting them;

https://www.thirdgen.org/forums/tech...l98-heads.html

They are easy to port and i recommend using them. Just go easy on that spot, only removing the factory defects. I admit i got a bit carried away back there but it was too thin way before i broke through. The only part of the bowl you should be removing much metal anyway is the common wall side since that is the high flow area and promotes swirl having a good port bias.

 

Oh about the long duration cams. I'm not a cam expert by any means that is something i brought up for sake of discussion that i have heard from other's. The idea is since the stock heads flow poorly you can make up for a bit of it by keep the valves open longer to let more air/fuel into the combustion chamber.

 

With iron heads, stay below 10:1 compression if you intend to use pump gas. I would keep it closer to 9.5ish.

If you're not going to do the port work yourself, you're better off investing in aftermarket heads.

Long duration cams work great, if you plan it all correctly. Unless you get one on a wider LSA (114°), then it's probably not the best cam. You'll make more torque on the bottom using a lower duration per lift than you will with a lower lift and larger duration, despite the heads being used. Only time I use long duration cams is for race motors that have a lift rule.

Generally, I suggest to people that they figure out their max. lift first, then find the duration.

 

Well I Could try the porting. i use to do 2 stoke engines. But should I go to a larger valve like 2.02, 1.60? or leave it stock with the 1.94s and such? In the future I plan on some aluminum heads, What would you recomend? i was looking at the Edelbrock e-tec heads.

 

Depending how "in the future" you're thinking, it may or may not be worthwhile to invest anything into your current heads. Changing out to aftermarket heads, especially on a larger cube motor - as you've got, changes the entire complexion of the engine. That changes how much cam you run, as you'd be most likely inclined to swap out to a more aggressive cam once you have heads that flow even better than what ported L98's would be capable of.

If it were my motor, I would skip the L98's and just jump the gun on a set of aftermarket castings, considering they're down the road anyway. Too many things change when you put on decent aftermarket castings. E-tecs are nice, however you would have to switch to a Vortec-style manifold, which you probably don't want to do. Shop around for heads with a 200cc intake or so, which is about right for a 383. Take a look at something like Brodix IK200's. $1100 for an assembled set. Which heads really depends a lot on how much you're willing to invest in them.