Hey everyone, I have a 1990 c4, six speed.

I plan to put a procharger p600b kit, with intercoolers. I want to run 10lbs of boost. I want to keep the stock short block for now and next summer rebuild it.

My questions are:

1. Will 36 lb injectors be enough

2. Will thease heads be ok
http://www.summitracing.com/parts/TFS-30400002/?rtype=1

3. What valve train do you guys recommend.

4. What runners do you guys recommended edelbrock, ect.

5. What is the best cam to use.

6. 58mm or 52mm throttle body.

7. any other recommendation or any opinions, would be appreciated.

Thanks guys for taking a chance to reply. I have had my C4 for over 10 years. I have saved my pennies for a long, long time. Now its time for the fun. I will post some pics once a start the build.
Best Regards, Walt

 

Hi Walt,

1. Yes 36's Ok but better to run a matched set of 60's. No matter what size you run it won't be enough unless you have a fix for the GM PWC. My eproms have that fix.

2. Do not know about heads.

3. Put a good set of needle bearing roller rockers on: 1.6:1

4. Leave the runners alone or simple change up to the TPIS Mini-Ram.

5. Cam choice based on intake.

6. Blower worth more with fixes to slip.

7. Spend money with me on injectors, Ostrich, and initial tune as well as fixes to ProCharger kit.

Best regards,
greg

 

I second that motion

(Hi Greg, still running strong )

Eric

 

1. Blower Wroks is the expert on this one follow what Greg says.

2. If you are doing the whole top end and heads thing I would do the AFR comp eliminator series, they flow massive amounts of air for a 23 degree design and get you in the C5 range of head performance. I dont think there is a better small block street head out there from all of the research I have done. If you are on a budget, I would look into having your L98 heads done by TPI's or Golen, which would run you in the $1250 range and be better than as cast trick flows or any other head, except the AFRs above.

3. Comp Cams Pro Magnum or High Tech SS roller rockers. Ratio to match cam heads.

4. Having owned a number of C4 cars, I am against popular opinion and prefer the L98 tuned port for its torque. My L98 cars have always been more drivable than my LT1 cars with an automatic trans. If you have manual, the LTI setup is the way to go.

Having said all of that, the supercharger adds a lot of low end grunt to an LT1 and with the progressive boost profile of a centifugal charger you want a top end style manifold to extract most power. So, I would do a mini ram. Either way TPI's parts provide the best perfromance for both styles of intake. To avoid confusion, I consider the mini ram an LT1 type of intake, and my LT1 car has a more low end grunt boosted than my tuned port cars normally aspirated, so much so that with a tuned port style you would do a lot of part throttle spinning and hook up will be more difficult. I have a hard time hooking my LT1 car and that is with a 2:59 gear.....

5. Comp Cams has a "305" LT1 cam (I believe you have an L98) with a 220/230 and approx .500 - 5.510 lift. If want the exact part number let me know. The LSA is 114 which is probably the minimum LSA you want for a blown car. If you get serious about the AFR heads, call comp cams and get a custom grind with intake in the mid 220's. Keep the LSA in the 114 -115 split.

6. Since you are doing the top end, a 58mm is a no brainer. If you were to keep stockish induction a 52mm will work fine from what I have been told.

7a. Other thing, dont get the 600B kit. The trans ratio is lower and you need smaller pullies for a given boost and will be prone to belt slip. Get at least the P1sc. See how much a D1sc upgrade is as you can spin it slower for a given amount of boost and with heads and cam you will have a lot of growth potential. You may have to spin the hell out of a P1sc to get 10lbs and with the p600 it may be futile. This will depend on how efficient the intercooler is. (The LT1 intercooler sucks and will limit a max effort setup with heads and cam, I dont know about the procharger L98 intercooler, I heard it may be better. If you call ATI and talk their tech should know).

7b. I can't say this with confidence for an L98 car, as I have an LT1 car, but if I were to do an LT1 from scratch, I would have bought a dedicated 8 rib bracket from blowerworks, go with a D!SC, fab a custom intercooler or go alcohol inj. You would spend the same amount of money but have a much more powerful package with plenty of room to grow. I dont know what the equivalent path for an L98 would be

AKS Racing on this site has a badass L98, ask him for advice. He also seems to have grown through a number of setups to a full custom and will know more than I do.

Also, Blowerwork is the foremost expert on C4 and even with a procharger kit can let you know all of the shortcomings.

I am interested in this also as I implied above, I have a blown 96 LT1 car and have been consider taking the plunge to supercharge my 89 L98.

Just keep in mind that once you go down this road, you will have a lot of tweaking and fine tuning to get all of the kinks out and you need to stay on top of everything. I bought my LT1 car with the procharger kit installed and by the time I am done with it, the only thing that will be left untouched is the blower head(P1sc), and even still that may get upgraded.

I assume you already know that you need forged pistons and good rods.

 

Highmileage,
That is exactly what I wanted to know. Its a good chunk of money and I dont want to buy the wrong stuff.

I spoke to Greg, he is going to set me up when I get my parts together.

Highmileage,
I will let you know how it turned out in the next few months. Anymore advice or tips would be greatly appreciated .

 

What one of thease three heads do you feel would be good. They are all AFR

http://www.summitracing.com/search/?...AFR-1040&dds=1

All of the heads also say that they offer a 75cc or 65cc combustion chamber. What one should I get.

 

depends on the compression you want to run

 

I am going to run on a stock bottom end for now. Next summer I plan to build a stroker.
For a stock comp ratio what would be the best choice.
Thanks, Walt

 

I am going from my loose memory so forgive me if I am a little off, but my comments should be in the ballpark.

The L98 head is 58cc and comp ratio is between 9 to 9.5 (I dont rememebr comp ratio) but head volume is definitely correct.

The thing to keep in mind is for about 10lbs of boost, I think you ideally need to be under 9.5 comp ratio and closer to 9. Also at 10lbs of boost you are in danger zone with an L98's cast pistons. They are even weaker than an LT1's hypereutectics.

For a 350, the 65cc probably gets you lower than you want to go if stock compression is 9.0. If its 9.5, it may just work out OK, would need to know the piston dish size to be sure.

For a 383, its definmitley better as you will not need as large of a piston dish for a 9 to 1 compression.

For reference my LT1 350 has Sealed Power blower pistons with -21cc dishes and I believe the LT1 head is 52 or 53cc. My calculated compresssion ratio is about 9.2 (it also depends on headgasket thickness). If memory serves me I have seen some 383 FI applications specify approx piston dishes in the -30's.

Best bet is to research 383 blower pistons to find the dish size available and pick your head volume to suit. Based on rough guesstimates a 65cc is probably closer to working in both 350 and 383 applications.

Hope this helps.
I have some 383 build sheets and can look up exact dish sizes from a couple of builds if you would like.

 

Highmileage,
I found -31cc pistons, that should bring the comp to about 8.5. So 65 should be good.

The more and more I look at superchargers I think that I should build the 383 first. Not sure what I should do first.. Any suggestions on a specific kit I should get. As far as brand, eagle etc.
Thanks, Walt