Desktop Dyno Guys... Where can I get.... *UPDATE* How should I build my 383?

[PhoenixZorn]

Don't have the 12-235-2 available on my DD2003... but I tried the 230, and saw almost no change... a 4 ftlbs increase, and a 4hp drop at the same RPMs...

 

[PhoenixZorn]

Anyone have piston suggestions for me?? I'm really in the dark about what the different piston styles can do... Flattop, Domed, Gas Ported... what applications are they all good for?

 

[dyeager535]

You are going to want to go with flat tops, and as long as forced induction/nitrous isn't in the future, hypereutectics are unquestionably the way to go for a non-race motor.

With Aluminum heads, I'd be asking some serious questions about how much compression you *might* get away with on 87 octane, if 87 is the goal. There are some rules of thumb, but if you can get some "free power" from increased compression, take it. Besides, aluminum heads essentially only save you weight, so the additional compression they can take (over iron) makes up for the power lost to iron heads.

 

[trailblazr81]

I have flat top TRW with area machined to clear valves. Dish and Domed are usually for changing compression ratio. Theres cast pistons, Hyper. and Forged. If you can afford the forged thats the way to go!! I'm no expert and Mine was a kit, crank, rods pistons. I pretty much buoght a 383 short block and added the rest. Make sure you get the block machined to clear the rods tho!!!

 

[PhoenixZorn]

I have a quote from my local engine builder guy to rebuilt the 327 to stock specs for about $1500... $2000 to build the 383, and he said if I give him a list of parts, he'll get them for me at cost... so now the real question is, how much power do I want in this truck that I may never build...

 

[mountain4x4]

Hypereutectics require less clearance than forged, they are a better choice for a street motor. I like Kieth Black pistons. As far as flat/dished.... go with whatever makes for the right cr. If you want a precise cr, you will have to adjust the chamber volume with porting/polishing, and check out the headgasket thicknesses available. Polishing the chambers is a good idea anyway, its easy to do, lets you tune more aggressively before detonation, reduces carbon buildup, reflects more heat back into the chamber where it can be used for power.

 

[sled_dog]

$2k isn't a bad price. I think i will have that much in mine before I'm done. I had hoped to do it cheaper, but oh well. I have SpeedPro Pistons. A set of flat tops for a 383 can be had for sub $200 off Ebay(what I paid). Same for a cast crank(as I also did). Most of my money is tied up in block and head work. As well as rotating assembly balancing, that and all the misc crap. I am going to run an LT4 camshaft. Using stock rods with ARP bolts. Everything will be held together with ARP bolts. I will let you know how the camshaft and head combo works out when I fire it up. Heads are off a newer Caprice Cop car. They are 285 HP crate motor heads(if you run them on Mortec). Ported and with the 383 I hope to be puting out like 300 - 350 at the crank. I know that sounds low, but consider the torque I'll have. 10.5:1 compression, very mild cam, 383, dual plane intake should all add up to gobs of bottom end. We shall see, its my first stroker motor. Should have it strapped to a Dyno sometime in like November(we have one at school).

 

[PhoenixZorn]

Sled Dog, did you ever put that stuff into Desktop Dyno?? I know it's not super accurate, but did you get what you are looking for on the program when you put in the parts you are using?

 

[trailblazr81]

This was a while ago but when I had my 383 done I was told it was only gonna be around $100 more for the stroker than just getting a 350. But this wasnt just a rebuild of my own. I bought a rebuilt and didnt have to give a "core motor". Remember when its all said and done you will probly end up spending twice as much as you were told the rebuild costs. I think Im $3500 into my 383. Probly near $4000 witrh the carb change.

 

[PhoenixZorn]

thats why this is a future project, and not something I'm going to jump into head first right now.... I'll get my feet wet first, make sure I have all my ducks in a row, then get the **** done all at once... first thing's first... i need to rebuild my blazer before I go building another engine...

 

[sled_dog]

somewhere around 300HP and upper 400s on torque. Considering a new camshaft. Think an LT4 hot cam will be a way better choice. Should be upper 300s on HP and the same torque(actually a flatter longer torque curve

 

[dyeager535]

If you can, I say put it together yourself. If you've got friends that build engines, the few specialty tools you'll need you can borrow.

I have no idea how much is in my 355, but I didn't really spend any more than I had to, except what I now consider a huge waste, the aftermarket roller cam.

I personally believe starting with a later 1 piece rear main, roller cam block is the way to go. Less leak prone, much cheaper roller lifter stuff. If I were to build mine again, here is what I would do (keep in mind what your desire is...mine is great low end, a little bit of topend, willing to trade top for bottom):

Block: later one piece rear main/roller. Preferably four bolt, not really important though. Minimum overbore.

Crank: Used cast iron

Rods: I'd go with stock, but if I could get a good deal on some Eagles or something, sure. 6" rods if they fell in my lap. Not sure if a 383 can use them though. Never paid a WHOLE lot of attention to a 383 build.

Pistons: Hypereutectic. Light weight, good strength, $100/set if you look carefully. Forged are overkill on a "mild" motor, cast are old technology.

Rings: Moly

Cam: It'd be a roller, but likely a takeout. I'd get the rest of the parts from the block or wrecking yard. With a 383, I'd cam it more aggressively than a 350 for sure.

Heads: tough call. No emissions required though. Fast burns just hold that light weight/great performance appeal, but a Vortec head on a low RPM carbed application is EXTREMELY cost effective and powerful. For a bigger engine, I think the fast burns win out. Since I'm fuel injected, I'd have to start looking around for aftermarket heads that mate up to either of the stock TPI bases, and have a fast burn chamber. Sportsman II's are it in that category that I know of.

Nothing wrong with gear drives, but again they seem to be overkill for basic engines...a stock nylon set runs easily 100K, the aftermarket double row/roller chains should beat that easily. I don't expect everything else in the motor to last 200K. A $60 Cloyes chain set would be more than adequate.

Stock oil pump more than likely, perhaps high pressure and run it with thin (10W30) oil.

I'd use ARP head bolts, I might stud the mains with ARP, I'd go with ARP rod bolts.

New balancer of course, I think mines a powerforce or something, $60.

Definitely balance the engine. Changing pistons, crank, rods, etc. all changes the engine balance, and while it may last without it, $125 (here) is worth it.

There's a TON of money that could be spent building an engine, but a "low" RPM truck engine doesn't require all the parts a go-fast engine will. Not that you should cheap out on things, but forged this and that really aren't required. Look what survives stock, and compare your needs to that.

 

[PhoenixZorn]

Dorian, all good suggestions, but remember, you built a 355, while I'm building a 383... yeah, I can buy one complete for $2500, with all the correct parts for a towing/offroad vehicle, but that wouldn't be fun... it would get shipped here, I'd drop it in, and be done with it... I also don't have $2500 to drop into a prebuilt motor... The difference between a 383 and a 355 is the stroke... 3.250" to 3.750", it's an amazing difference... of course, when I did a .060" overbore, it dropped the HP and torque, so sometimes too much displacement can be a bad thing... 388s are not better than a 383.

I'll more than likely stick with a chain drive, though a friend of mine just had his 355 built with gear drive, and it sounds mean. I'm going with the fast burn heads because no other head could match it for hp or torque in Desktop Dyno... If another head comes along that can beat it, I'll definitely use it. I'm also going to end up using a flat tappet cam unless I can get my block machined for a roller cam... if I can get it done, I'll be using a hydraulic roller cam and lifters... I'll be using aluminum rods, forged pistons, and a 400 Crankshaft unless I find an Ealge one cheaper to just buy.

If you can build a 355 to 410hp and 495lb*ft using all the parts you mentioned, and get a strong low end torque curve, then perhaps I'll reconsider my build... but I don't think it's possible to get that much power out of a 355 without spending a small fortune...

 

[dyeager535]

355 or 383, makes no difference on the parts, (in regards to cost) it's your end usage that determines how much money needs to be spent to keep it together. You can spend just as much on either motor if you want.

My goals were a very strong low end motor that got good economy. If I were building for power, my HP and torque numbers would have been very different and so would the area where they peak. The displacement would probably be different if economy wasn't a big consideration. The parts used would be much more expensive to hold up in the areas that the higher numbers come in. As it is, I've got a *TPI* 355 which really restricts upper end power. Even if I wanted to play around with different cams, the induction would be the restriction. Carbed, you won't have that kind of bottleneck. Why spend money on forged this and that, when I will never see the RPM's or load that requires them? That money could go towards buying $1000 heads.

According to DD2K (and I hope to actually get it dyno tested once I get the tune ideal) I'm peaking at 425ft lbs at 2000RPM, and 275HP at 4000RPM. IIRC, SDPC got over 400HP from a similar setup with more cam, so HP isn't really a valid comparison as you can see. Cost of parts is though. A 383 is going to be torquier in the first place, comparing different displacements and their power figures really isn't helpful IMO. A 400 will potentially make more power than a 383, but you draw your own line of what is "enough".

Aluminum rods are not a long life item as far as I know, can't think of any long term (warranty) automotive application that uses aluminum rods stock.

 

[trailblazr81]

Ive seen 383's using Vortec heads mild hydraulic cams and 9:1 compression making about 350HP and 460 lb/ft. torque. HP peek is under 5000 RPM and peak torque in the low-mid 3000's. Nice inexpensive truck motor. I would think if you were trying to do this on a budget to not use roller cam. But definately if your gonna spend $$ in one place do it on heads!! Good flowing heads with maybe a 218 duration at .050 cam and 9:1 compression with good quality parts and you should be good to go.

 

[mountain4x4]

I'll be using a hydraulic roller cam and lifters... I'll be using aluminum rods, forged pistons, and a 400 Crankshaft unless I find an Ealge one cheaper to just buy.

Don't mean to ba an a$$, but these are all the wrong parts. These are all race parts, except a cast stock crank. The roller cam is a waste of $, alum. rods are for drag racing (don't last), forged pistons would be great for a motor making over 500hp and in a race car, but they require more clearance, expand more, and do not seal as well as hyp. on a street motor. Why would you possibly use a 400 crank when you can get a cast eagle 383 crank for under $200?

Alum heads might be worth the $, its debateable, but for this motor theyre an expensive luxury, you probabaly would never notice the difference between them and a $500 set of Vortec heads. If you want to spend the $, AFR heads are considered the best.

 

[dyeager535]

Alum heads might be worth the $, its debateable, but for this motor theyre an expensive luxury, you probabaly would never notice the difference between them and a $500 set of Vortec heads. If you want to spend the $, AFR heads are considered the best.

I'll disagree with this part. Aluminum heads reduce weight, and those particular heads are ten times better than stock Vortecs. (no argument on cost though, price difference is pretty great) Vortecs may flow well, but they weren't designed for a 383. As supplied, the fast burns have better components as well.The fast burns absolutely trounce the Vortecs in both exhaust and intake flow numbers. (better for a larger engine)

As to AFR's, well, they don't have fast burn chambers last I checked. More compression with less detonation means more power. The AFR's may flow great, but flow isn't the *only* thing that makes heads good.

For about $900 you can get Sportsman II's which are iron AFAIK, but have the fast burn chambers, and I *believe* take a standard intake.

Dated article, but still some idea of what head differences there are from the comments. I'd expect the Sportsman II's and the fast burns to be improved over what they list there. head test

 

[thor]

Dorian, Those aren't the current production of afr heads in that arcticle. That is from 2000 and they have had a major redesign or two since. Take a look at afr's site and the current 195 cc heads, they are like cnc art, they are cnc machined, and have fast burn chambers. Only bad thing about the afrs is the fact they are on backorder for 12+ weeks currently.

 

[dyeager535]

Not being argumentative, where do you see fast burn chambers on their site?

A bit bigger chamber (than the fast burns) though too.

 

[thor]

No arguement taken, simply stating thos were "old" heads in the comparasion. Here is the only pic of an AFR combustion chamber from the sight, they don't call them fastburn just like dart doesnt, but the shape is there....

I haven't used a set of the fastburns, but I was suprised to see the recommendation of a 210 cc raised intake port for a low rpm torque motor.