Okay,
Thanks to some stellar input from Forum members and one outstanding website (thank you 65Z01 - I don't even know you, but you've been educating me for days) I think I've just about got my build list for when I get home this fall. Any thing I'm missing or suggestions? The goal is to get my 90 Vert (6-speed) under 13 sec without mortgaging the house. Do you think this will get me there? Right now, I can't get to my car, so all I can do is dream and work on my to do list for when I get home. Thank you for the input and suggestions. :cheers:

Underdrive pulley set
K&N Air cleaner set
Frisbee removal
MAT Sensor relocator kit
Modify Mass Air Flow Sensor for increase cfm
Air Foil
52mm TB Base
Power Coupler
Stage II EPROM
170deg stat
Adjustable Fuel Pressure Regulator
Roller Cam (I can't find the stats right now and am open to suggestions)
Port the plenum and upper runners
Port the stock exhaust manifolds
Magnaflow performance cats
Magnaflow cat-back exhaust
Line Lock Kit - Because I like to smoke 'em
Extensive headwork to include port/polish 2.00/1.60 int/ext

 

I don't mean to sound bad but a lot of those mods might just be a waste of money if you want much improvement.
MAT Sensor relocator kit
Modify Mass Air Flow Sensor for increase cfm
Air Foil
52mm TB Base
Power Coupler
Underdrive pulley set
Port the stock exhaust manifolds

All the mods I just mentioned will give you very little gain for the price you will be spending. I suggest a good set of long tube headers, and a superram intake (if you can afford it, if not porting the stock intake sounds great), the roller cam would be a good idea, a good set of heads would really give you some power as well but they are expensive. Start with cam, headers, catback, and porting the intake, these will give you some good gains.

 

:iagree: for the most part. However, if you're going to do a cam, you should do the cam and heads together. Remember, try to get the components to match as much as possible and do things together with a "package" mentality. :)

 

Thanks; here's my take on those mods:
-Underdrive pulley set, maybe a little gain
-K&N Air cleaner set, also do the cut lid for a total of around 10chp
-Frisbee removal, yep, 10chp here
-MAT Sensor relocator kit, no gain but cleaner
-Modify Mass Air Flow Sensor for increase cfm, yea do it though not much gain
-Air Foil, no
-52mm TB Base, if you do this get an AS&M with integral air foil
-Power Coupler, don't know but not likely any gain
-Stage II EPROM, hold off on this one till all mods are in to see if it's needed
-170deg stat, just go with a 160 deg & fan switch for max gain
-Adjustable Fuel Pressure Regulator, for sure this and base timing will be used for tuning
-Roller Cam, a good cam is worth 30chp on a modified TPI setup
-Port the plenum and upper runners, sure
-Port the stock exhaust manifolds, weeel ok, but more important is a 2 1/2" mandrel-bent front Y pipe
-Magnaflow performance cat, sure
-Magnaflow cat-back exhaust, ok
-Line Lock Kit - Because I like to smoke 'em, lol
-Extensive headwork to include port/polish 2.00/1.60 int/ext, yep, this is worth 25-30chp. You can to go 2.00/1.56 valves with stock seats; to 2.02/1.60 with new seats. In either case you should carefully unshroud the intake a little as well as shape the spark plug boss. Just do mild porting & blending to hold down port size; flow & swirl are far more important than size here. Just smooth the ports a little, blend the guides & seats into the bowl and widen the bown a little on the near side (get David Vizards books on building SBDs). Don't foreget the valve train work, i.e. RRs, 7/16" studs, Ti retainers & 10deg locks. If you chose the ZZ-9 go with 1.6/1.5=int/exh RRs; with the 219 cam go with 1.5RR around. Don't foreget the 7-angle valve job.

Since you will be shifting higher I would also suggest some ignition work to assure solid spark up there. I like the HyperTech setup along with good wires and cut-back plugs.

With those mods, since you have a 6-speed I suggest you initially do the siamese intake base. This will improve top end breathing enogh to allow you to shift in the 6k RPM range. Later you can throw the big $$ at an after market intake if you need more.

I believe you have 3.07 or better gears in your D44 with that 6-speed so you should be running well below 13s. Check out Vic'89s performance; with 3.07s and stock cam & heads he is well into the 12s. Of course he runs a good set of DRs too.

Good luck with those mods; I think you will be very pleased with the results.

 

Thanks everybody for the feedback. 65Z01, I had wondered about the Siamese intake base, and I'm still trying to put my fingers around that one. The theory makes sense though. That's a great website you've got there, thanks for the instruction.

Your right about the gears, I'm still running the stock 3.07 rear. Once I get done with the power side, then I'll start playing with transferring it to the tires and will probably go with 3.73 gears. Once I get the power to the tires, then I'll work suspension and traction to make it stick. Then all that will be left will be to :steering: :thumbs:

 

Since you've got some time to think about it, I will throw my .02 into the mix. I did all the "cheap" and "free" mods. They add up alot of money and don't give that much in return, but the true free ones are worth doing if you have time. If I was to do an L98 again from scratch, I would hit the big stuff and not waste money on expensive things that don't make power. Here it is on the cheap.

LT1 intake conversion (I don't think it can be beat, for the money)
Stay with the stock TB
Stay with stock FPR
Definately spend the money on your heads (use thinner head gaskets)
Comp cams xtreme energy grind matched to head flow #'s
LT Headers (used or uncoated, just get some)
get rid of pre-cats/hollow out your cat
cat back exhaust
Custom burned prom (not off the shelf)

This should be a good base to build off of. Ok, I'm ready for the heat!!!

 

if your going to do cam, heads, lt-1 intake and exhaust i would do a 52mm TB it will help it breath espically with the cam and heads.

 

My friend makes over 370 rwhp in a 97 F-body with a 48mm TB shorty headers and home ported heads. 224/236 comp roller. If he's got the money then great, but the money could be used on his heads. Later the TB is easy to get at and it would help keep us on a tight budget!

 

Okay, since we're talking heads (which are definitely getting done) would I be better off putting the money into mine or going with after market? I like the LT1 intake idea. Is this a direct replacement or is there more involved to make it all work together?

One Note though - I am currently stationed in California so smog inspections are a definite concern. The cats have to stay and all the other smog stuff has to work and look correct.

 

Well since you are currently on the left coast you can't touch the exhaust in front of the cat and may not get away with changing the intake, at least not visibly unless the part has a CARB number on it.

So, for now gut the two pre-cats and install a 3-stage hi-flow cat along with the cat-back.

If you have the $$ you might think about an Accel base with AS&M LT runners for good low end plus better top end or a super ram to realy push top end with a little low end loss. Remember if you install an LT1 intake you will be converting your L98 to an LT1; it all depends on where you want the torque.

 

this is true

 

After building the 383 for my 74 Nova, I'm very familiar with CARB numbers. That was the biggest reason for porting the stock exhaust manifords and keeping them on there. I'll use the high flow cats and a cat-back for the exhaust, so that's set. I'm also thinking that by doing the work to my current heads, I can get the performance and still look correct. I'll go just like I did on the 383 heads: 2.02/1.60 with new seats and 7-angle grind, stainless steel pro-flow valves, 1.6 roller rockers, screw in studs, high compression springs with all the locks and guide plates, port & polish, and thinner gaskets. It'll be about the same money as good heads, but these will still "look" correct. All of this with a ZZ9 cam should make for a good base and then I can start playing with the induction. That's the easiest part to change anyway. I'm off to look at intakes. Man, I love the internet! :thumbs:

 

The LT1 intake(in stock trim) is legal to use in California as it has provisions for egr and such, but when it is converted to use a rear stand up distributor, the egr has to go. In your case the conversion might not cut it. I thought it could save you at least $500. If you want to see it done check out Johns site http://www.lt1intake.com You can do the conversion yourself or buy it from him complete. I don't know if the SR has a CARB # or not. I believe that the big mouth and runners do though. When it comes to what you can/cannot do in CALI, I couldn't tell you. I'm just a dumb country boy that lives in the sticks. We don't even know what CATS/EGR's do, so we take them off and throw them in the bushes.

 

Now that is a COOL looking set up! I was just looking on the for sale page and just missed out on a Super Ram that a member was sell Very reasonable. That would have been nice. I'll keep looking though.

I know what you mean about the CARB stuff. I'm from a little bitty town in no where Kansas and can't wait to get back. 4 more years and I'm done and heading home. Of course, I'll go home in a LOT nicer car then I left in. :lol:

 

That LT1 is a very nice conversion, but because of the EGR I can't go that route. Thank you for the tip though. I spent a little time going through his site and he has obviously put a lot of thought and effort into developing a nice package that someone like me can work with. :thumbs:

 

forget about the Mass Airflow mod, 1990 L98's use speed density efi system and do not have MAF's

Check out forum member Joe90 website. He makes very nice power with a modified TPI setup.

hmmm, the stock exhaust manifolds are probably going to limit you. I picked up 30+ rwhp from hedman 1 5/8" long tube headers and 2 1/2" dual exhaust. are there no 50 state manifolds for L98's?

 

If you want a superram, here is one priced very cheap on ebay... http://cgi.ebay.com/ebaymotors/ws/eB...sPageName=WDVW

 

Chillcat, Thanks for the tip on the superram. I'm off to check it out and figure out how a superram works.

Dave

 

I like the idea of a LT1 conversion. What would I gain over the 90 L98, and what all is involved with the swap.
Thanks
:seeya :steering: :auto:

 

Check out http://www.lt1intake.com to see what is involved in the conversion. What will it do for you? That depends on your cars current state (mods) and where you plan to go!