C4 Tech/Performance L98 Corvette and LT1 Corvette Technical Info, Internal Engine, External Engine

383 Dillemmon?

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Old Mar 25, 2017 | 08:42 AM
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Default 383 Dillemmon?

I purchased a stock 87 fairly recently and I'm not too excited about the torque. I'm currently building a 383 for my C2 and the bug kicked in. On the 87, I had to replace the timing chain & gears so I pulled a few caps off the bottom end and the bearings are pretty well shot. Decided to slap it back together and drive it a bit before tearing it down. Here's the question.... and this is a "future" type inquiry... planning stages. 383's are easy to build, so I thought I'd pick up a roller block at a junk yard and start the process. With a mild cam, can I just drop the 383 in and leave all the rest stock? No racing intended... just would like a little more torque. I don't have time to be messing around with major computer/fuel system mods. Side note: I just deleted the cold start injector and installed new Accel injectors. Will it at least run if I just swap short blocks? Or is the computer going to shut me down?
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Old Mar 25, 2017 | 09:32 AM
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I'm running a 400 small block with 24# injectors in my 87. It runs fine accept the idle is a little unstable until the motor warms up a bit.
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Old Mar 25, 2017 | 10:24 AM
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Originally Posted by steven mack
I'm running a 400 small block with 24# injectors in my 87. It runs fine accept the idle is a little unstable until the motor warms up a bit.
Was is just a remove & replace with no other messing around?
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Old Mar 25, 2017 | 11:08 AM
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Originally Posted by steven mack
I'm running a 400 small block with 24# injectors in my 87. It runs fine accept the idle is a little unstable until the motor warms up a bit.
How much power is it making? I know my injectors aren't going "static" at 43 psi fuel pressure and we are running 42. Car is making 420 RWHP so I am guestimating a high end of 500 at the crank.
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Old Mar 25, 2017 | 12:06 PM
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Just removed and replaced.I will eventually get a chip burned for the 400.I don't know how much power I am making ,But I know there is a lot more to be had with my engine combo.
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Old Mar 25, 2017 | 12:17 PM
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There is going to be some tuning involved. your adding 34 ci. so engine will require more fuel. Cam choice can also require some tuning, I would do research on other builds to minimize tuning difficulties.
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Old Mar 25, 2017 | 12:47 PM
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Originally Posted by steven mack
Just removed and replaced.I will eventually get a chip burned for the 400.I don't know how much power I am making ,But I know there is a lot more to be had with my engine combo.
I agree so go estimate what you can get. So if I know I am estimated to make 450 to 500, get injectors sized for that.
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Old Mar 25, 2017 | 12:50 PM
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Originally Posted by Kevova
There is going to be some tuning involved. your adding 34 ci. so engine will require more fuel. Cam choice can also require some tuning, I would do research on other builds to minimize tuning difficulties.
I have 33 city more than stock but making almost doubled the 240 HP it came with. At this point, I wouldn't bother with tuning difficulties. Let the tuner suggest the combination and he can figure out the tune which is what I am paying for
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Old Mar 25, 2017 | 02:16 PM
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Originally Posted by steven mack
Just removed and replaced.I will eventually get a chip burned for the 400.I don't know how much power I am making ,But I know there is a lot more to be had with my engine combo.
That's what I was hoping. Baby steps first. Thanks for the "inspiration".
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Old Mar 25, 2017 | 06:02 PM
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If you don't have a tune don't go bigger on injectors You can wash your cylinders down and dilute your oil with fuel.The Maf will compensate some.You need to decide what you want to do intake wise and as been metioned find simalar builds like yours.That is what I am doing.Like you said baby steps is O.K.
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Old Mar 25, 2017 | 08:07 PM
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..... I put a 406 in my '87 years ago with an adjustable fuel pressure regulator set at whatever the percentage increase in Cubits was over the stock 43.5 psi ... As I recall it was something like an 18% increase ... it ran fine without touching the chip ..... 406/350 = X x 43.5 or in your case 383/350 .....

Last edited by C409; Mar 25, 2017 at 08:09 PM.
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Old Mar 25, 2017 | 09:51 PM
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That's good info C409.
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Old Mar 25, 2017 | 09:56 PM
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Originally Posted by steven mack
If you don't have a tune don't go bigger on injectors You can wash your cylinders down and dilute your oil with fuel.The Maf will compensate some.You need to decide what you want to do intake wise and as been metioned find simalar builds like yours.That is what I am doing.Like you said baby steps is O.K.
To a point, it will adjust. Still, why run it like this? Just get a dyno tune and skip the shenanigans and be done with it.
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Old Mar 26, 2017 | 07:29 AM
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Last winter I built a 383 with stock L98 heads and intake, 24# injectors and a mild cam, (comp came 08-302-8) with stock tune it ran well but rich, I ordered a mail order tune and it still ran rich, the tuner sent me another tune and it ran much better with that tune, since then I have learned to do some data loging and make my own adjustments.
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Old Mar 26, 2017 | 09:15 AM
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Mail order tune is, IMO "guess a tune" unless they datalog and make adjustments.
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Old Mar 26, 2017 | 09:16 AM
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Originally Posted by Kevova
.......I would do research on other builds to minimize tuning difficulties.
That's what I'm doing for the 383 I'm building now but it's a carbureted app.
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Old Mar 26, 2017 | 09:20 AM
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Originally Posted by aklim
To a point, it will adjust. Still, why run it like this? Just get a dyno tune and skip the shenanigans and be done with it.
Unfortunately, I don't do "dyno tunes". If I can't tune it myself, then it's out of my league and for somebody else with deeper pockets. I'd rather buy a new guitar than spend money on a dyno tune. LOL
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To 383 Dillemmon?

Old Mar 26, 2017 | 10:12 AM
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Tom under 200 gets you an AEM 02 sensor kit from Summit
If you have a carb easy to tune it to perfection wont be a whole lot different that EFI at least how it "feels"
a 400 in a TPI car has to be a blast.
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Old Mar 26, 2017 | 10:29 AM
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Originally Posted by Tom454
Unfortunately, I don't do "dyno tunes". If I can't tune it myself, then it's out of my league and for somebody else with deeper pockets. I'd rather buy a new guitar than spend money on a dyno tune. LOL
If you don't have deep pockets, you need to minimize risk and plan properly. So for example, I won't pay to have a base manifold installed, 3 months later do a throttle body and then do a upper intake. You plan to have it all done at once. Yes, it costs more up front but saves in the long run. You don't take unnecessary risks by screwing up the fueling and have it ruin the motor or lean out. Also, while it runs "just fine" by screwing around, you lose mpg which, IIRC, costs money in gas. Penny wise, pound foolish.

I saved a few hundred bucks doing TFS heads a long time ago. How cool was that. Instead of having deep pockets and buying the AFR heads, I bought TFS since the specs were good enough. Worked out so well that when I pulled the head I found that all the valves were wobbling and one of them kissed the piston of a 5000 short block.
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Old Mar 26, 2017 | 05:10 PM
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Originally Posted by aklim
If you don't have deep pockets, you need to minimize risk and plan properly. So for example, I won't pay to have a base manifold installed, 3 months later do a throttle body and then do a upper intake. You plan to have it all done at once. Yes, it costs more up front but saves in the long run. You don't take unnecessary risks by screwing up the fueling and have it ruin the motor or lean out. Also, while it runs "just fine" by screwing around, you lose mpg which, IIRC, costs money in gas. Penny wise, pound foolish.

I saved a few hundred bucks doing TFS heads a long time ago. How cool was that. Instead of having deep pockets and buying the AFR heads, I bought TFS since the specs were good enough. Worked out so well that when I pulled the head I found that all the valves were wobbling and one of them kissed the piston of a 5000 short block.
I do all of my own work.... including valve jobs. I have Sioux equipment. I do guides, seats, 3 angle valve jobs and I build complete engines from scratch and overhaul manual and automatic transmissions etc. So.... "have it all done" is a foreign term for me. LOL As planned, this car might get 500 miles on it per year at most, and it won't be raced. Today I finished installing a set of Accel fuel injectors. The biggest problem was that pesky 5/32 heat embrittled vac line that keeps breaking when you look at it cross-eyed. That sent me on an unexpected trip to AutoZone.

I have 4 EECIV Mustangs and a EECIV Crown Vic so I'm comfortable with fuel injection, but I have to spread the cost out so dribs & drabs it will be. Based upon what people have said here so far, I think I can build up a roller-block 383 and just drop it in with an adjustable fuel pressure regulator and then take it from there at my own pace.

Anyhow, now I'm shopping for the software for OBD1.

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