383 or not?

[bucket]

Sweet sounds pretty simple, what's a good one cost?

Depends on you definition of good. $100-$150 I'd say.

 

[skysurfer]

Thanks for the correction Swims. Alcohol fueled post on my part.

 

[HotRodPC]

A 383 is just a 350 with a .030" overbore, the rest of the cubes come from the longer connecting rods. Hardly on the edge of blowing up.

Actually the 383 has shorter connecting rods to compensate for the longer stroke of the crank. What a 383 motor is, is a 350 block that is .030 over as sky said. BUT, it uses a small block 400 crank that is turned down on the main journals to fit the 350. THe connectiing rods are also SBC 400 rods. The only sbc con rod that isn't 5.7 inches from center to center. It also has to use a SBC 400 harmonic balancer and flywheel, so the rotating assembly needs to be all re-balanced after the mods are made. This is why its usually best to stick with a Stroker kit.

 

[HotRodPC]

uummm aint 383 longer stroke crank as in a 400 crank with 3.75 throw or stroke compared to 3.48 on the 350?

not longer rods.?

besdies that if it were to the point of running a blown up engine, why the heck would ANYONE spend big bucks building one, much less brag about having a 383?

sorry but your friend is way off.

I think he is thinking of when someone bores one out to .060 over. I have heard alot of ppl talk about the cylinders being too thin in that case, prone to crack, or overheat due to alot of heat build up and transfer without proper cooling between them etc.

Ahh, I see now Swims already jumped in on that. Although, even at .060 I think the 350 will be OK. I think where the friend maybe getting confused of the overheating is confusing the 400 rotating assembly with the 400 block siameses cylinders and steam relief holes in the 400 that are needed. 400's did have tendancy to run warm due to the siamese cylinders and no water between cylinders, and a 400 could be taken to .030 max, and that was only some of them, or they tend to have overheating problems. In this case, you're still running a 350 that is not siamesed cylinders, so the heat issue is not big a deal. Of course if you run high compression or a big cam with lots of valve overlap that allows exhaust to roam around in the head, it will run warmer. That is all normal and why you should want to improve your cooling system if running a performance cam, especially if sitting in traffic alot.

 

[Boogiedown]

Well turns out the motor is .060 over, like I said my buddy don't know too much about the SBC, and I am just learning myself. So I guess that would make it a 388? Does the .060 change anything, af far as reliability ?

 

[crazy4offroad]

Being bored that much is a lot but I would still take it for the heads. Run er till she blows, by-God. You'll still be ahead with all the goodies you're getting.

 

[HotRodPC]

Well turns out the motor is .060 over, like I said my buddy don't know too much about the SBC, and I am just learning myself. So I guess that would make it a 388? Does the .060 change anything, af far as reliability ?

The only way to know for 100% sure is to do a sonic test on the block after its disassembled. I've known several 350's to go .060 and were just fine. I do beleive there are a few years they suggest not to go over .030. Most machine shops won't bore a block unless they feel its safe to bore it .060 over.

 

[Green79Scottsdale]

Actually the 383 has shorter connecting rods to compensate for the longer stroke of the crank. What a 383 motor is, is a 350 block that is .030 over as sky said. BUT, it uses a small block 400 crank that is turned down on the main journals to fit the 350. THe connectiing rods are also SBC 400 rods. The only sbc con rod that isn't 5.7 inches from center to center.

Actually you use the 5.7 inch rods from the 350ci. The 400ci rods are shorter (I believe 5.56? iirc) than the the 350ci. You make up any difference by moving the wrist pin location in the piston to put the top of the piston where you want it.

 

[Boogiedown]

Well guys I made the trade, I'll pick it up maybe next weekend. Then I have to wait about 50 days till I get the truck to put it in. I think I'm gonna put it in the 77 but I gotta wait for it

 

[Boogiedown]

Being bored that much is a lot but I would still take it for the heads. Run er till she blows, by-God. You'll still be ahead with all the goodies you're getting.

I like your style man lol

 

[HotRodPC]

Actually the 383 has shorter connecting rods to compensate for the longer stroke of the crank. What a 383 motor is, is a 350 block that is .030 over as sky said. BUT, it uses a small block 400 crank that is turned down on the main journals to fit the 350. THe connectiing rods are also SBC 400 rods. The only sbc con rod that isn't 5.7 inches from center to center. It also has to use a SBC 400 harmonic balancer and flywheel, so the rotating assembly needs to be all re-balanced after the mods are made. This is why its usually best to stick with a Stroker kit.

Actually you use the 5.7 inch rods from the 350ci. The 400ci rods are shorter (I believe 5.56? iirc) than the the 350ci. You make up any difference by moving the wrist pin location in the piston to put the top of the piston where you want it.

Yes, that is true as I've stated. All small block rods are 5.7 center to center except the 400. The shorter 400 rod is what is used in the 350 block to stroke it to a 383 @ .030 overbored. And yes the wrist pin location is differant for the compression height. If you used standard 350 pistons you'd push the piston out of the cylinder and it woudln't be a pretty sight.

 

[HotRodPC]

Well guys I made the trade, I'll pick it up maybe next weekend. Then I have to wait about 50 days till I get the truck to put it in. I think I'm gonna put it in the 77 but I gotta wait for it

Coolness !!! So are you going to tear it down and freshen it up with a new ball hone job, new rings and bearings before you install it???

 

[bucket]

Coolness !!! So are you going to tear it down and freshen it up with a new ball hone job, new rings and bearings before you install it???

...and here comes the slippery slope.

 

[89Suburban]

...and here comes the slippery slope.

Yup.

http://www.gmsquarebody.com/forum/showpost.php?p=49895&postcount=284

 

[DirtyC30]

...and here comes the slippery slope.