Hello everyone. I'm finally getting my L98 back together, you can see the parts I bought on my site, www.cardomain.com/ride/471099 and my dad's car is on page 11, we were in the paper with it.

I am wondering, if anyone has advanced the stock cam 2* or 4* and seen any gain at the track in MPH, loss in time(faster), or at the DYNO. I am going to use my stock cam for now, in my 350. But I am going to be using 1.6 comp cam pro magnum's I got used from a friend in perfect shape for
$140, then you can read everything else on my site, it's on page 3, for what I'm doing.

Check out my car clubs forum too, I'm always cronsformula, or cronsformula350. On AIM or YAHOO messenger, I'm "formula3fity", I'm not always on, but some of the time. Well let me know what you guys have done. Keith

 

The stock cam is so small, you would be better off retarding it, not advancing it. Retarding a cam makes it appear bigger, while advancing it makes it appear smaller.

 

I could also retard it, I have a cloyes 9-way adjustable timing chain, so that helps too.

Yeah the stock L98 cam is only .310 gross lift, 115 LSA and just enough duration for the TPI intake. But I am going to be using it with WORLD sportsman II heads, they're good enough to support 550 horses out of the box.

They could use some bowl blending, but with the stock cam, by the .310 lift range, it still has a 70% exhaust/intake flow ration, so that helps. I want to try the heads unmodified, then I'll port them.

I had ported the stock L98's, one had coreshift, but I already had over 31 hours of port work into them, my machinist finished one head, then went to the other. I was going to 2.02/1.60's, and if I stuck with 1.94's, I wouldn't have had a problem at all.

My machinist went to SAM racing in Houston Texas, he said, the bigger valves don't hurt velocity that much. I was also moving the valve guide over some while also doing a 5 angle valve job. So I already had the valves, since I spent 550 on them, had a bunch of other work done to. But I had the good one flowed.

The first pair of heads I ported, well the good one tested. Flowed at .550 lift on the flow bench. 280cfm on the intake and 200 on the exhaust.

I have some pics www.cardomain.com/ride/471099 on my site, of my porting room and some of the heads and my HSR later. My other cam is .555/.576 lift and @ .006 with the 1.6 comp cam pro magnum, it's 295 int/298 exh, but I need a chip, stall, 255 LPH pump, a cage, and a few other odds and ends, so I'm going to wait, then do it, refer to my page 3 of my site for more info.

Thanks for some help though, that's what this is for, Keith

 

I called TPIS and talked to Chris, I've talked to him in the past. He said advancing it 4* is good, it will improve the torque to 430 to 450 lb-ft. He said retarding it, would make no sense. That would usually drop the torque off, quite a bit, and the power would be about he same, so I advanced the cam 4*, and I'll be getting 400 C.I. torque out of the motor with the TPI, and when I use the HSR, it will work even better for torque, I am using 1.6 roller rockers, on the world sportsman II heads. Because one the factory L98 heads, had factory core shift.

I am also using long tubes, followed by a x-pipe modeled after the burns stainless steel models, I'll use some elbows, followed by bullet mufflers; because they behave like a megaphone on a bike, then dumps before he axle; one of TPIS airfoils, descreened maf, with the fins removed. And I'm using a '91 intake I ported, stock runners, and a massaged plenum, and I am sure the car should be running 103-105 mph.

Because with bad traction, even after I had lakewood LCA's and panhard bar. Without Nitto's the car still ran a 13.81 at 99mph, until the trans broke the 3-4 clutch pack. It still ran a 14.86 at 86mph. My formula only ran a 14.86 at 93 mph with three gears, so it definitelly launched well.

I just thought I'd let you know.

 

[quote=cronsformula350;3358228]I called TPIS and talked to Chris, I've talked to him in the past. He said advancing it 4* is good, it will improve the torque to 430 to 450 lb-ft. He said retarding it, would make no sense. That would usually drop the torque off, quite a bit, and the power would be about he same, so I advanced the cam 4*, and I'll be getting 400 C.I. torque out of the motor with the TPI, .[/quote

Retarding the cam 3 degrees would see the best gain on a stock head, intake and cam tpi. I did this intial on my build up when money was an issue and the seat of the pants torque increase was huge. You might see some power gains by advancing the timing up top but at the expense of low end torque and mid range. The Lingenfelter book you talked of in another thread should have a section on engine building and the benifit of cam timing and the effects on performance.

 

Sorry, you must not have gone to my website, I'm using 200 CC world sportsman II's, with 2.02/1.60's and stock, there good with a dual pattern camshaft to make 550 hp. I'm not using the stock heads, and if you would have checked, I'm using these instead. The stock L98 heads, I ported, and at .550 lift I got 280cfm intake, and 200 exhaust. The machinists were impressed that, I got those numbers for my first set of heads I worked on. But the one with coreshift, threw the project off, so I got the sportsman heads for $775.00

I was told by the guys at TPIS that know tons of stuff about the stock cam, that with 4*, that it would increase the torque dramatically, but the hp would stay the same. Then I am using the same cam, with the holley stealth ram, and later upgrading to a nasty cam I have, read my website, page three.

I actually spoke to John Lingenfelter, he agreed that I may become the next John Lingenfelter, based on my knowledge, tuning charactistics, and experience. I know quite a bit about cam timing, I have last built a 650 horse pontiac motor, and have talked to tons of engine builders, including Tom Nelson, and with them in person at rourte 66 and other places, to become very knowledgable about engines.

I am also using a TPI intake that I ported to 1205 intake gaskets a while ago, and It in combination with shorties on my Iroc-z, same stuff as my formula's stuff. After 11 runs, I started at a 15.1 at 89mph, and after 11 runs, I got the car to a 13.89 at 99mph, I have the slips to prove that, with 140K on it.

 

WOW!!!! I shoudl let everyone on here know that you can talk to the dead and are goin gto be John Lingenfelters sucessor. He has been dead for years by the way. You asked for imput so I supplied you with information of my building experience. Personally i think your heads are way to big right now for your stock intake. hopefully your plans to upgrade soon come through.

Asfar as those flow numbers for l98 heads? That just accredits you to just what kind of person you are and anyone who would read this with knowledge of these heads woudl agree.

 

I spoke to john, before he died, and before he had his 190 mph accident, I think you misunderstood that.

I am not using the stock intake, mine is ported to the max. I'm just rying it out, with these better heads, then going to my ported holley stealth ram, go to my page one of my site, and see what I've done with mine.

I had my iroc running a 13.81 at 99.0 mph with traction trouble still, because I had the suspension, but stock LCA's and Panhard bar, stock converter, gears, but I did other work, it's on page 8 of my site. John told me, I have the spirit and knowledge to become the next John Lingenfelter in the future if I keep it up.

My formula is going to be way faster, long tube beaders, x-pipe, duals, dumps before the axles, 1.6 roller rockers, angle plugged heads, and manual steering, with 51% crank underdrive, and 23% for the alt, and I'm only going to have the alt. and water pump running off the motor. Weight reduction, and the car is going to run great.

I have a nastier cam, BUT I have to get a chip for it burned from Ed Wright, from Fast Chip, a larger fuel pump, larger injectors, roll cage; Then I'll run that cam, I know the stock cam is terrible, it's only .310 lift, that sucks!

My other is .555/.576, already ground 4* advanced, so it has a 116 LSA, and at .550 lift it's 288 int/.293 exh duration. It's pretty serious, but it would run like hell with the stock tune. Right now, I'm putting about $2250 into the car, just to have it running again, I have accumulated parts for a while.

I got the manual gear for $250, roller rockers for $140, and cam for $150, that cam in a tuned LT1, ran high 11's, tuned for it, with stock heads, and intake, so any questions?

 

What is the point of this thread? If you ask for advice and tell everyone they are wrong then what is the point?

If you know everything then let it be.

 

I agree. I supplied my imput that is all I can do.

 

Well, Unless someone can prove to me with their slips, then I'll believe them; but after I ask professionals and they have proven and verified that 4* timing works, so that's what I'll do.

If you want and you can, go ahead and delete this post. But anyone, that asks questions, theres a lot of people that don't know much, I know a lot, I was offered a machine shop job. But I musn't know much. But I have proven what I have know by track time, and that showed me what I know, by track time, and mph. And the first time at the track at route 66, over 11 runs I went from a 15.1 at 89 MPH, to a 13.89 at 99 mph, and that was in my "87 IROC-Z L98 car after 138K so hmm, that must have been like a bad twilight zone? NOT!!! I must know know some of what I'm doing; and that was with the cam, straight up, stock. ANd usually you would advance a cam to gain some power or torque, not retard it, especially after you speak with a lot of machinists, that have made motors with over 2800 hp.

 

I've got a 91 (107k miles), belonged to a buddy of mine, who still has a slip for 13.81 sec at the strip from the car; had a chip, airfoil, K&N filters, and some good tires with a good driver. I may be forgetting something, but there wasn't much done to it, and it ran about the same time you're talking about- just to put things into perspective.

The current wisdom may indeed be advancing the cam a few degrees on certain motors with certain cams. It's all about getting max piston speed lined up with the middle of the intake lobe centerline of the cam, so you're sucking the most air through the motor. A 20 year old fuel injected 350 is a different animal than a 2800 hp big block, and each individual case must be considered separately. In this case I'd tend to go with Kevin 91Z's suggestion of retarding the cam a bit.

 

Well, I have already talked to my shop that builds engines, and has done a lot of TPI motors, and they also did, the same thing, and they dyno'd it and use the same 1.6 roller rockers, and they tried different methods of getting power with a totally rebuilt engine. They found out that advancing the stock cam 4* is the best method also, not just TPIS, but that's ok, I just don't wanna argue, it's just what I have found out my self.