Hey guys, I ran a 1.975 60 ft. but ended up running a 14.629 at the end. It's loosing a ton of top end and I have an idea but wanted to know your opinion. It's a 383 stroker with 10.2:1 compression, crane 2040 compucam, custom chip, stock 86 TPI plenum and runners, Accel 1,000 cfm TB, stock IROC exhaust manifolds, 22 lb. injectors, 40 psi, 2,500 stall, 3.73 posi with 28 in. tall tire. Now that you have an idea of the combo, I know it sounds like I'm choking for more air, better runners and plenum and headers, but I don't have the money to spend right now on that. My idea is, one of the reasons I'm loosing power top end is because the stock distributor only puts out enough spark till 4,500 rpm. Anything after that, I loose power. Could changing the module and coil make a real noticable difference? I've talked to a couple of people and they've all told me that running that 60 ft I should be in the 13's. Any opinions and suggestions would be appreciated. Thanks

 

I doubt it will make any difference at all. The stock ignition system is good for far more RPM than the induction system is. Until you get rid of all the restrictions in the intake and exhaust tracts, it will never, ever produce power at any RPM above the stock power curve, no matter what ignition you use. If you don't have enough money to fix the actual limits to the car's performance, don't waste what money you do have on something that won't do a thing.

Kind of reminds me of a guy at a parts store that I knew; he used to tell a lie about how Roscoe came in one time and wanted a starter, which was like $28 at the time. Well Roscoe only had $25, and begged and pleaded with the guy to sell him the starter for $25 because he couldn't drive the car. Of course he couldn't do that, so Roscoe ended up buying $25 worth of air fresheners and chrome cigarette lighters and crap like that. Next Friday, there was Roscoe standing at the counter again with $25, begging and pleading for a starter. So since he couldn't get the starter again, he bought some more useless garbage for his car that didn't work. The next Friday..... you get the point. Don't be like that, save your money for what you really need instead of blowing it on stuff that does you no good.

 

So the module and coil wouldn't change a thing? All of it lies in the runners and manifolds?

 

you definetly need a better induction set-up as well as a good exhaust. That engine sounds like it will run hard after that

 

On mine I had a full aftermarket exhaust from headers back. Y-pipe got a little crushed on one side. Replaced it and picked up 6mph. I can't imagine how bad your full stock exhaust is hurting it.

 

TPI was originally designed for a 305 so throwing it onto a 383 is like putting a 283 2-barrel intake and carb onto it.

- Get some 1 3/4" headers
- Get a better induction system (SuperRam, Miniram, Carb)

Simple as that.

 

I'd say that is keeping you back quite a bit.

Get a new intake and exhaust and you'll be screaming.

 

That crane cam 2040 (210-216dur .440-.454L LSA114)
is to small for a 383.It will run out of breath at 5000rpm in a 350.What heads are you using?

 

I agree that the stock TPI and exhaust is holding you back. But it sounds like something else might be amiss. I ran a 1.96 60' on my 355, with the stock TPI, single cat 3" exhuast with edelbrock headers. Yet my car ran a 13.6, a full second faster than yours. Granted, I've got a better exhuast, you've got more cubes, I still shouldnt be a full second faster. What was your mph? And what heads are you running? Also, your fuel pressure seems a little bit low, you might try bumping it up to around 47 psi.

 

I ran 92 MPH, I have 1.94/1.50 heads with 76cc combustion chambers. Just to save myself from the embarrassment, I didn't pick out the combo. When I bought the car it had this engine in it, he said something about a 383, but the way it ran I didn't really believe him. Then all of my problems started, I come to find out he changed the lifters without changing the cam. And he set the lash wrong, wiping out 7 lobes, pulling the rocker studs out of the heads and circulating a ton of steel throught the engine. Plus, to make things worse, he didn't weld the pickup to the pump! The pickup was laying in the bottom of the pan. I knew the oil pressure was low for about a week, but just figured the sender was bad because it didn't knock. So I rebuilt it cheap, it had a 2050 cam, but the stall seemed wrong, so that's why I put the 2040 in, just incase he didn't change it. After rebuilding the engine, that's when i found out that it was a 2,500 stall. I know that if I throw on a set of 2.02's and an aftermarket TPI along with headers the car would definately scream, but with all the money I have wrapped up in it, it's for sale now and I was looking for a way to get a little better time in the 1/4 cheap. I still have a Chevelle to build that I plan on doing the whole combo correct, this just turned into a big project that I didn't plan on. But on a positive note, I did learn a ton about fuel injection and how cool it is when it's set up right, that i never knew before.

 

Oh, one more thing, here's my time slip:

Reaction- 1.284 (I know I was sleeping)
60 ft.- 1.987
330 ft.- 5.945
1/8 et- 9.322
1/8 mph- 72.57
1,000 ft. et- 12.197
1/4 et- 14.696
1/4 MPH- 91.52

This was my first run, I can't find the slip for my last run where I had the 1.975 and the better et, but you guys get the idea.

 

If i were you i'd go punch the guy in the teeth that sold you that car. I got $5 on it being a 305, and a poorly running one at that.

You can't explain (not even) 92mph any other way. Stock TPI can run 100mph even unported even with stock heads/cam on a 350.

Wish i could help you more, but looks like you have MAJOR problems or misinformation under your hood. Until you get to the bottom of exactly what you have, and exactly what condition it's all in there's just nothing more that anybody can do for you.

 

There's hope. I've seen 383s run 14s before, maybe it's just put together really badly. I think you've got a lot of work ahead of you. Just to be sure what it is I'd ID the block and make sure it's at least got a 4" bore.

 

Yea, I'd verify that what you have is actually a 383. If it is, then there's tuning issues to deal with even before you unchoke your motor. your nice 60' time doesn't even really carry over to the 330ft mark. seems like it launches hard, but after that it gives up.

 

Thanks for the replies guys, but I put the engine together correctly. It has a Summit cast 3.750 in. stoke crank, and the block is a 1978 350 out of a pick-up truck. The car runs great, all I was looking for was the module and coil question. I plan on going back to the track next Sunday to test it some more. I plan on adding fuel and time to see where it gets me. I'll let you all know what, if any, difference it makes.

 

One more thing, when I went to the track to get the time slip, my friend with his 97 Camaro went also. We both ran two runs side by side. I took him off the line and was door handle to door handle until we got close to the finish and I lost horsepower and he took off. He ran a 14.2 and I ran a 14.6. He was at 103, I was at 92 mph. Like I said before, the car has a ton of torque, it's the hp I seem to be missing. Or I could be running out of the powerband.

 

What i was trying to say is that your timeslip looks normal for a strong 305 with some minor issues (like lord knows what custom chip and injectors, etc)
If it's a 383, it has major issues though to slow down that much.

And it's not uncommon for people to sell cars lying about what it has and what is done to it.. That's why i'd verify what i had so i knew what magnitude of problem i was chasing.

 

Heres a timeslip from my car way back when it was stock with a cat-back. I'd say its right on the money (tuned wise) so this is what a mid/low 14 second timeslip SHOULD look like:

60': 2.157 (no wheel spin, 3.27 posi, stock converter)
330: 6.090
1/8: 9.278
MPH: 76.74
990: 11.975
1/4: 14.381
MPH: 97.45

 

Thanks! It looks like I'm loosing power early, our 330 ft times are identical. Man, now i don't know where to look.

 

Heres another thats even more like yours. This one is from when my car was completely stock.

60': 2.147 (no spin, 2.77 gears)
330: 6.097
1/8: 9.372
mph: 74.67
990: 12.155
1/4: 14.661
mph: 92.93

 

What RPM are you shifting at?

A 350 with stock intake won't breathe anything more than 4800 or so, with that 383 you are lowering the HP curve even more (a 383 needs almost 10% more air than a 350, so the RPM where it runs out of airflow will end up about 10% lower - or around 4400 rpm). Yet your cam wants to breathe, and your gears want the motor to wind higher in the RPM's. Thus if you are shifting at 5500 then you are probably majorly hurting your power output. sad to say but you should be shifting in the 4's.

I say it's just a mismatched combo and it won't run right until you get a real intake and exhaust on it.

Also keep in mind that once you open up the intake and exhaust and let it breathe, you may run into problems maxing out the airflow sensing ability of the MAF, which then puts you into needing custom PROM work. You say you have a custom chip now - what's been done?

In the meantime. give it a tuneup, check the compression, yada yada yada

 

I've been shifting around 5, but I have some info I wanted to share. I just found a brand new set of SLP runners that I could purchase, and I'm still checking on the headers. If I got the runners without the headers, how much of a problem would that cause?

As for the PROM, the guys that I've been working with have programmed it for a 383, and if by chance I get a code, they'll help me and reprogram it.

 

the slp runners are decent if you really hog them out to make them truely siamese.

not as good as with headers, no, but at least a help.

the lower intake is a major restriction too.

it would also be interesting to know as well, what exactly they've done to the prom to make it run on yoru engine...have they ever used a data logger to read the aldl data stream and tune based on that?

 

I went racing yesterday and came to a conclusion that a set of heads, headers and an open exhaust would be my best bet. The heads are the most restrictive part of the engine right now, and like all of you have mentioned, the stock manifolds aren't helping either. I bought the SLP runners for $150 from Summit (they are on clearence so if any of you would like a pair, get them while they last.) and I couldn't pass up the price. To make a long story short, my time didn't change a bit, still loosing power at top end. But it's not a big deal because I already have the car in the Auto Trader. I think it would be a nice car for someone that wanted to invest a $1,000 in World or Vortec heads and a 3 in. exhaust. But any way, thanks for all the help and suggestions, it was much appreciated.

 

91L98Z28:
They didn't hook up the ALDL because they are in Tennesee and I'm in Ohio. I wish I had that convienence though.

 

I'm running a 383 also but running 13.48 with stock TB, stock intake. I swapped to a 58mm TB bigger injectors and adjusted fuel pressure up and ran 14.07. Then made a ram air setup lowered fuel pressure and ran another 13.48@103 on street tires and 13.34@102 on slicks, I'm going to try swapping back the stock TB and see what that does. Maybe the 58mm is to big for the stock intake. Might be better on a Mini-Ram or something.

 

What heads are you running and do you have the stock exhaust manifolds? I have found out that we both have a ton of air entering the engine, but I know mine doesn't have the right flow exiting the engine. I just took the car to a better track the other day and got a 1.925 in the 60 ft., but still only ran a 14.6 in the 1/4 at 90 mph. I have the bigger TB, SLP runners and so on, but the heads are 1.94/1.5 with 76 cc chambers. I've been looking for a head with 2.02/1.6 but I still need the 76cc chamber to keep it streetable. If I go any lower in cc I'll be above 10.5:1 compression and I don't want to have to run race gas. But I figured that who ever I sell it too, they can drive it the way it is, or put $1,000 in it and get pretty close to the 12's.