Hi Guys,

I just put my 383 (89 IROC) on the road about one month ago. Stock 2 bolt 89 IROC block, cast Eagle 383 crank, reused stock rods (resized&reconditioned), Speed Pro Hyper Teflon Coated Pistons, 10.1:1 comp, Vortec heads - bowls blended, screw in studs, Manley valves, SDPC TPI Vortec Intake, Lingenfelter 74211 cam, TPIS valve springs, AS&M LTRs, Ported Plenum, 58 mm BBK Throttle Body, Cold air intake behind fog lights, SLP 1&3/4" headers, SLP catback exhaust, test pipe, Spohn SFCs, Spohn LCAs, & Spohn Torque Arm, "built" 700R-4 with 2600 stall Vigilante, stock 9 bolt BW 3.27 gear, & BFG drag radials.

After about 10 runs, my best to date is as follows: 1.72 60 ft, 7.98 1/8 ET, 85.7 1/8 mph, 12.59 @ 107.1 1/4 mile. The car is consistent in the low to mid 12.6s at 105 & 106 mph. The car is hooking great off the line - zero spin. I'm having some minor shift point adjustment problems (shifting around 5500-ish), but overall the car is running pretty good.

It seems to me that the ETs are OK, but the mph seems low to me. Do my times/mph seem OK to you?? Does anyone out there have a similar setup? If so, what kinds of times/mph are you running?

Sorry for such a long post. Thanks for any help you can offer. Looking forward to your replies.

Later............Mike

 

That ET is very close to that MPH.

When I had my 383 and 3.27 geared 9 bolt, I was able to run high 11's at 117 mph. My engine had the HP for the mph but the gearing wasn't right for the tire size. It could have run mid 11's with the proper gearing.

 

Stephen, thanks for the reply.

So are you telling me that you think my car is working like it should be?

I know that my engine is a mild 383, and is not making "monster horsepower", so maybe high mid 12s @ 107ish is all that it can do.

Mike....

 

Your mph is an indication of HP. ET is the traction. You mention no wheel spin. When you enter your ET and MPH into a HP formula you'll see that the HP is almost the same. That tells me the combination is working well. If ET was slow, the formula would show a much lower HP.

Guessing that you and your car are close to 3500 pounds your rear wheel HP from ET is 346.6 and HP from MPH is 335.6. You have a higher HP from ET so you're getting real good traction however it looks like the engine is losing power on the top end a bit. Maybe try shifting at 5700-6000. That first to second gear shift in the 700R4 is bad. You need to over rev first gear so that when you shift to second, the rpm fall back into the sweet spot of the torque, not below it.

You should be able to get 108-109 mph with that ET.

 

Thanks again Stephen. That's a big help. I'll try that next week when I go back to the track.

Mike...

 

From the mods you describe, it only seems like you have a high RPM breathing problem due to the long runner set-up. But it still makes 350hp at a low rpm, which is good. I think that if you were to go with an Accel SuperRam, your hp would go up to about 400 and add 5 or 6 mph to your speed. You are probably making 425lbs o'torque with your setup now.

 

Thanks for the reply Paul. I can't say that I was considering a Superram setup (unless I could find a good deal on a used one), but I am planning on having an LT4 manifold modified to fit my car. Do you think that the LPE 74211 cam I'm running would be OK for an LT4 manifold setup (or a Superram)? I just finished this motor about 2 months ago, so I'm not going to fiddle with it too much right now. Plus my wife will throw me out of the house if I spend much more money/time on car stuff. I also have a '91 ZR-1 which I spend a fair amount of time & money on as well (runs 12.0s @116 mph). Thanks again....Mike.

 

Mike,

Just in case you didn't know, the LT1 manifold is almost an exact copy of the TPIS Miniram, except the LT1 motor is reverse flow cooling. The Miniram would require no modifications to bolt up other than the fuel rail kit. You will not preserve the bottom end with that manifold though, its small plenum volume and short runners are meant for high rpm breathing, and vortech heads cannot support a 6000rpm 383.

But you can get a SuperRam, which will peak out your power in the 5300-5500rpm range, enough to make good hp, and not too much to ask from the heads.

I think the cam would run fine in your motor, but even better with the intake manifold. You will re-use the base intake and can sell the runners and stock plenum to make up some $.

If you do it right, it should run about the same as your ZR-1 and still have the ability to pump it up more (nitrous or Supercharger).

 

hummm still good numbers, this is giving me a good ideal on what my motor will be running once it goes in my formula, anybody have any ideas on my setup, hp and et, times roughly ??

l98 block with 383 eagle kit, +.30 over,kieth black pistons, and rods, eagle 383 crank
lt4 hot cam
23degree trickflow heads
mini ram
52mm trottle body
slp 3/4 headers
underdrive pulleys,free mods, and stock injectors,dual ram air

3.27 aussie disk rearend
3200 torque conveter
corvette 700r4
steve sphonns lca and relocation brackets
alum driveshaft

sorry that was long, just wondering , any help or guesses

 

I really hate to "guess" about this kind of stuff, because there are so many variables when talking about engine combinations (not to mention drivers). But if I was guess, I would say that your combo should be in the low 12s with around maybe 112mph. HP I would say you would be around maybe 430 ish (just a guess). Your stock injectors MIGHT be a problem, but I do know several 383s running stock injectors with no problem (but I'm pretty sure that you are pushing the stockers to the limit). Compared to my setup, I would say that you have better heads and of course you are running the miniram, which is easier/better to drive at the track than my LTR setup (due to the better high rpm capability w/o so much immediate low end torque). I just switched my rearend from a 3.70 back to my stock 3.27, and picked up 4 mph w/o losing any 60 ft time (the 3.70 was KILLING my LTR TPI setup on the big end of the track). However, you might benefit from a little more gear (like a 3.70), just the opposite of me, due the higher rpm breathing capability of the miniram. It looks like it should be an awesome ride !!!!!

Just my best guesses. Good Luck !!

Later, Mike......

 

Your et and mph are correct for your set-up. With my old set-up, I ran a 383, 9.1 compression, AFR 190 heads, superram, crane 2032 compucam, and ran 13.06 @ 106 consistently. I never made it in the 12's, but could have with more runs and tuning.

That motor dynoed 300 hp at the rear wheels and 380 tq. Your mph is about the same, so you are making around 310-320 at the rear wheels, which equals 400 at the crank. Your et is better than mine because of your convertor.

Changing intakes to the superram should get you another 2 mph. Anything more than that you need to have the superram ported upper and lower. It is still a restriction compared to the LT1 intake or miniram.

The hot ticket now is to run a converted Lt1 intake, I'm getting one converted now, just to try out.

 

just a question how is it he's only turning around 350 and im turning about 450 with my setup, im new in the whole bit, my engine was built by Ugly Duck Performance in Washington, and it dynoed at around 450...heres the sig...

 

Looking at your sig I don't think you dynoed 450 at the crank with that set up. Anyway, we are talking about rear-wheel hp here, which is roughly 20% less than crank hp. Don't mean to rain on your parade, but that combo doesn't look like it makes 450 hp. What is your mph in the 1/4 or 1/8 mile?

My old set-up ran 105-106 mph in the 1/4 and 85 mph in the 1/8 with 300 rear-wheel hp and 380 ft lbs of tq. My car is about 3800 pounds with me in it, so those times are about right for my set-up.

 

Thats pretty good mike!

Timj Siford (TRAXION) on the boards here had a similar setup in his stock 90 IROC 350. He had the ASM runners and ran 12.50's as well. He bolted on the mini ram and went to 12.24.

I think if you swap on the LT1 intake, it will work wonders for you. I think you are outflowing what the TPI can feed for you.

Good luck! Sounss good so far!

 

Thanks for the replies 89GTA338 and Guido.

That's good advice - I was kind of thinking about trying one of the modified LT1 intakes. However, I don't want to get into a whole bunch of parts changing (due the $$$). Do you think that the LPE 74211 cam that I'm currently running will work with the LT1 intake? It's a perfect cam for a LTR setup, but I wonder how it would work with the LT1 setup. I do have a friend with a 94 LT1 Z28 running the 74211, and his car runs great (12.6s @110). I guess my big question is, could I get away with changing to the LT1 intake, and leaving everything else the same??

What do you think? Thanks in advance for any help that you can offer.

Later, Mike.......

 

1/4 Mile ET: 11.900
1/4 Mile MPH: 114.780
60 Foot ET: 1.712


1/4 Mile ET: 11.986
1/4 Mile MPH: 109.140
60 Foot ET: 1.613

thats on that motor so you guys tell me????


like i said i was wondering if that sheet was correct or it was some other sheet......

 

What are the specs of that cam mike?
Im not familiar with their line of camshafts so dont know the specs.

 

i just ordered a conversation lt1 intake from john, for the price i dont think i really had a choice ~ , cant wait to bolt it on, i will be running a lt4 hot cam, ??,

dont know guys, 383 with good heads and intake, and bored out, with meaty cam,with all the free mods and extra hp mods, i would think u would get atleast 400hp at the wheels, i guess the papers show the results but just seems a motor like that should have higer hp,
you guys making me think about my 383 now lol, hummm maybe i should have went with a 400 block ?????? 20% for drive train sounds like alot, dont know maybe just me, but i will take your word for it since you have that setup allready

how much rear wheel hp would a 400hp viper and the new 500hp viper, have ?

 

Guido,

LPE 74211 cam: 211 int, 219 exh, 112 LSA, .499 lift int, .525 lift exh (.533/.560 with 1.6s, but I'm running the stock stamped steel 1.5 rockers). You'll notice that it doesn't have quite as much intake duration as some of the other cams out there. It is one of the cams that Lingenfelter recommends for an LTI/L98. (He only sells 4 cams for these engines, and two of them are for a supercharger and the Superram). I figure that it should work with an LTI intake. However, ZI like the look of the TPI (that's why I went that way initially), so I'm thinking of maybe just switching over to the AS&M SS LTRs, and selling my regular AS&M LTRs, and leave it at that.

Thanks for any advice.

Mike.....

 

My opinion, if yuo want to really squeeze the ET and HP out of your engine, put the LT1 intake on it, and put a cam in it with at least 224 duration on intake and exhaust. That should REALLY pick up.

 

Thanks Guido. I'll start looking into that combo, and see what I can find for a camshaft. Just for starters, did you happen to have a specific cam in mind when you recommended 224 I/E duration (or were you just speaking in general terms)?? My springs can only handle .540 lift.

Thanks,

Mike.......

 

Get the comp cams HR270 roller(I think) ground on a 112 ls. The duration is 224-224 .525 .525 110 ls.