I'm rebuilding a stock '94 LT1 with 111,000 miles. Going with a cast 383 crank, HE pistons and better rods. Looking to build a very reliable and reasonably fuel efficient daily driver where torque and throttle response are considerations, not just peak horsepower. Heads will be mildly ported (bowls and good valve job, maybe bigger valves if warranted) and I'm leaning toward a Hotcam at this point, doubt I'll go with anything a whole very much bigger. Exhaust will be mid length or full length headers with a Magnaflow 3" catback system. I used to install Motec and Electomotive EFI setups so tuning will be dialed in with a laptop using the stock computer and a wideband O2 sensor. Using a 4L60E transmission that will get a modest stall converter of 3000 or less, rear end ratio is 3.42 and will stay that way.
This is not really a tight budget build but I do have better things to do with my money than spend $300 dollars for this part or that part that delivers little real improvement in power or reliability. Not really interested in bragging about trick parts that don't deliver value. My intention is for this engine to go 100K plus miles and not use oil or have reliability issues.
I'd really appreciate any input from people who have real experience here, not just regurgitated magazine quotes. Several details of the build are being mulled over and researched, here are a few I haven't found much info on in the archives. If you have any well supported opinions on any of these questions then your input is appreciated. Don't be ashamed to help on on just one or two questions if you have something to say that might help.

Considering the cam size and application is there a power gain or reliability improvement that justifies going to roller rockers? I'm thinking the 383 could possibly deliver a decent power gain from the increased lift but if it would be only a slight gain then I'm content to stay with the stock rockers assuming they don't have reliability issues with this cam size. If you think the roller rockers are the better choice then an opinion on whether a $140 set of CC magnums would deliver similar gains and be at least as reliable or more so than the $250 Pro Magnums would be helpful.

Considering the engine size, cam size etc. what type of gain is there from going with the larger valves assuming the bowls are resized to match? Anyone have any recommendations on reasonably priced valves in the larger sizes? I'm thinking that expensive race type valves are overkill here because of the modest RPM and cam specs.

I want this thing to run a long time, would it be prudent to go ahead and replace the stock lifters considering the mileage or do they run forever? If you have a recommendation on the lifters other than stockers fire away.

About cam choice, bigger isn't always better in my book. Not really looking to build a peaky race engine with substantially degraded fuel economy and driveability. From what I've read I think the Hotcam would work very well. Would the next size up, say a CC 306 cam ( lift .510, .540 ex, duration of 230 and 244 exhaust) be easing into the range where fuel economy starts to take a dive and idle quality/ driveability and low/mid RPM throttle response is significantly degraded compared to the Hotcam?

Related question: leaning toward the Keith Black HE pistons right now, I want to run close clearance for quiet and longevity ( .002" or less). Any opinions on whether there are better HE pistons than these for my intended use. Also haven't decided on rod length. I can buy the rotating assembly with 5.7" or 6" rods, for a mild street engine intended to run a long time is there any reliability/ wear difference between the pistons for the two different rod lengths? There are tons of ring choices out there, I want a set that will last very well. Any suggestions on a particular brand/model of rings to deliver a good seal for many miles?



I know this is a lot to digest, after some input I may break it up a bit more in multiple posts so I'll get more bites. I suspect these are common questions that a fair number of people consider when building similar nonrace engines but not as many people post on milder performance builds.

Thanks, Michael from Birmingham, Alabama

 

LT4 hot cam is pretty small and tame for a 383. I had an XE 230/236 in my car before. Had almost no lope at idle but had great throttle response and torque everywhere. You could punch it at any rpm and the car was happy to go. Loved that cam. A 2800 stall converter is all you need with it. You can use 3.23s or 3.73s. 3.23s will only hurt you in 3rd gear WOT. 3.73s are great.

I'm currently running a much bigger cam with 3.73s and didn't notice any fuel economy difference between 3.73s and 3.23s in the city.

You could pick up 20+ hp at 6400 rpm with 1.6 roller rockers. I think its 15hp at 5700 rpm.

For longevity you actually run your bearing clearances a little bit looser than tighter.

I went with 6" rods for less lateral movement and wear.

 

I'm running the CC503 XE. It's 224/230 - 112. In my 383 the drivability and economy of the car is close to stock. I could easily drive it every day, though I don't. But the XE cams are hard on valvetrain components, so all of mine are upgraded.

I would definitely replace the original lifters... it would be a shame to build an essentially new motor, and have a few tired parts in it. Stock replacement lifters might be good enough, depending on your cam choice.

For a really tame DD on a budget, the Hotcam kit might be your best bet. In a 383 it will drive like stock, and includes RRs. But most people would say that the Hotcam (and even my cc503) are too small for a 383.

Just be sure of your purpose for the car. My motor was built to be a daily driver. After putting all that $$$$ into it, though, it didn't feel right using the car for the daily commute... so now it's only a weekend toy. If I could go back in time and do it again, I'd go with a more aggressive cam, etc.

 

Thanks for the reply. It will definitely be a daily driver for the forseeable future so I don't want a gas hogging topend oriented powerband. I talked to a machine shop guy who just built a 383 with bowl ported vortec heads and the hotcam. He said it had awesome midrange snap and torque and revved out plenty well for a steet car you want to last 100,000 miles.
If anyone else has any suggestions please chime in.
Thanks, Michael

 

get a custom grind and have the perfect cam insted of the best "off shelf" cam.