Is this a 383?

[haysonj]

Originally Posted by SLDPULR

Was I correct that the crank journals on the 400 crank are different than that of a 350? I have read so much in the past few days that its all starting to blend together.

Yes the main bearings on the 400 are larger. But the big difference in the after market 3.75 stroke crankshaft is they are lighter and the counter weights are smaller so you need less clearenceing. They also can be internally balanced so you can use the 350 dampner. I bought a steel crank with scat 6 in rods and forged pistons for around $1200.

[67 chevelle]

Originally Posted by SLDPULR

Was I correct that the crank journals on the 400 crank are different than that of a 350? I have read so much in the past few days that its all starting to blend together.

I believe they are the same

The last 383 I built I got an eagle "internal balanced" kit for , runs like a dream , and your standard accessories ie , 350 flexplate , and harmonic dampener will work with . This is for a 2 peice rear main , as all one piece rear main 350s use a weighted flywheel but neutral balanced dampener

[GMB1985]

I bought my 383 kit from skip white performance out of Kingsport tn. It comes with a scat crank h beam rods probe pistons your choice of flat top or dish, king rod and main bearings flexplate and balancer an it's all internally balanced that is what you want the engine will last longer if it's balanced correctly I paid right at a grand you won't find it cheaper anywhere with those parts and internally balanced just my 02 cents

[SLDPULR]

Originally Posted by GMB1985

I bought my 383 kit from skip white performance out of Kingsport tn. It comes with a scat crank h beam rods probe pistons your choice of flat top or dish, king rod and main bearings flexplate and balancer an it's all internally balanced that is what you want the engine will last longer if it's balanced correctly I paid right at a grand you won't find it cheaper anywhere with those parts and internally balanced just my 02 cents

That is exactly what I am looking for. What did you do for heads? I have been looking at the summit cast heads. I like the price but I don't know if I should go aluminum heads or not. I would like to run a big but streetable cam and I'm not sure if the summit heads will be able to take the lift.

[SLDPULR]

Originally Posted by GMB1985

I bought my 383 kit from skip white performance out of Kingsport tn. It comes with a scat crank h beam rods probe pistons your choice of flat top or dish, king rod and main bearings flexplate and balancer an it's all internally balanced that is what you want the engine will last longer if it's balanced correctly I paid right at a grand you won't find it cheaper anywhere with those parts and internally balanced just my 02 cents

I just looked up there site they have kits for .60 what would the CI be on a .60 bore

Nevermind I found a formula it would be 388

[GMB1985]

Edelbrock makes a street head that's pretty decent for a grand or you could get a Chinese procomp head for around 600 a pair then you have to think about rockers a good set of roller rockers will cost around 300 bucks. I'm not trying to tell you what to do but go look at that website at there kits. The heads you can get from summit free shipping I'm buttoning up my 383 now I have about 4g in it. It doesn't take long to add up the cost

[turp mcspray]

IIRC, .060 over is 388cu. I wouldn't bore it any more than it needs.

[GMB1985]

Like a 385 or something. I wouldn't go that far over bore the thicker you can keep your cylinder walls the better I went 30 over because there wasn't much wear in the cylinders

[SLDPULR]

Originally Posted by GMB1985

Edelbrock makes a street head that's pretty decent for a grand or you could get a Chinese procomp head for around 600 a pair then you have to think about rockers a good set of roller rockers will cost around 300 bucks. I'm not trying to tell you what to do but go look at that website at there kits. The heads you can get from summit free shipping I'm buttoning up my 383 now I have about 4g in it. It doesn't take long to add up the cost

I saw those procomp heads on ebay. Are they any good? What about the dished vs flat top pistons? Is having a higher compression ratio going to make it require race gas or will I be able to get away with 91?

[SLDPULR]

Originally Posted by GMB1985

Like a 385 or something. I wouldn't go that far over bore the thicker you can keep your cylinder walls the better I went 30 over because there wasn't much wear in the cylinders

I dont plan on going .60 over. I plan to have this truck for a long time and if I can go .30 and get 10 years out of it and still have another rebuild left in the block. It has been rebuilt before and that worries me. I need to buy a ridge reamer or pull the pistons out and mic them at the bottom. The ridge is so thick on the top I cant get a good reading.

[GMB1985]

The procomps are the bottom of the barrel in my opinion. The higher comp ratio the less street able it is going to be I would try and stay around 10.5 to 1 that's a good medium. Flat tops vs dish is a matter of opinion also I used flats just because the heads I've got dish would have put me to over 12 to 1 you can't beat a good flat top

[GMB1985]

You need to measure the cylinders your pistons weren't stamped were they which doesn't mean much tey could have not done it you just need measure it before you go any further with your build and have your machine shop inspect it for cracks

[haysonj]

Originally Posted by GMB1985

The procomps are the bottom of the barrel in my opinion. The higher comp ratio the less street able it is going to be I would try and stay around 10.5 to 1 that's a good medium. Flat tops vs dish is a matter of opinion also I used flats just because the heads I've got dish would have put me to over 12 to 1 you can't beat a good flat top

Not quite sure what you are saying there, the dish piston is a low compression piston You just barely get to 12 to 1 with a flat top and 64 cc heads and a zero deck block

[haysonj]

Originally Posted by SLDPULR

I saw those procomp heads on ebay. Are they any good? What about the dished vs flat top pistons? Is having a higher compression ratio going to make it require race gas or will I be able to get away with 91?

You will need to get a lot more info before you start buying stuff You need to know about quench, zero decking the block and a lot depends on your camshaft and timing whether you can get by on 91 gas. A flat top will get you close to 10 to 1 which you can run 91 gas if you have your timing right

[SLDPULR]

Originally Posted by GMB1985

You need to measure the cylinders your pistons weren't stamped were they which doesn't mean much tey could have not done it you just need measure it before you go any further with your build and have your machine shop inspect it for cracks

They only thing I have to measure the cylinder with is a regular sliding mic. My problem is that the carbon ridge build up is so bad I can not get a accurate reading. They did not stamp the pistons.

[mgchevyparts]

I suggest you find a reputable engine builder to determine correct heads/pistons etc. You're going to make a mistake without professionall help.

[haysonj]

Originally Posted by SLDPULR

They only thing I have to measure the cylinder with is a regular sliding mic. My problem is that the carbon ridge build up is so bad I can not get a accurate reading. They did not stamp the pistons.

You might try the auto parts places like Autozone and O'rileys have loaner tools and they might have a ridge reamer you can borrow.

[SLDPULR]

Originally Posted by mgchevyparts

I suggest you find a reputable engine builder to determine correct heads/pistons etc. You're going to make a mistake without professionall help.

I am going to take this to a dirt track engine builder down the street from me. He comes highly recommended by a few different people that I have talked to in OKC. He will do all the machine work, check for cracks and give me all the specs on the motor. My next door neighbor has built a few motors and is going to help me with the build. I am just trying to get a game plan after I get all the specs from the machine shop.

[SLDPULR]

Originally Posted by haysonj

You might try the auto parts places like Autozone and O'rileys have loaner tools and they might have a ridge reamer you can borrow.

I went to Napa today to see if I could buy one and they did not carry them. They have them at the warehouse by my work so I will try and get one tomorrow. No offense to anyone that likes autozone but I refuse to step foot in one. Maybe the autozones in other city's are worth their salt but none of them in Oklahoma are worth a darn.

[frank69]

In the early 70's they started dropping the compression ratio, what they did is dish the pistons like yours are. The earlier engines had flat top pistons and they had about 10 to 1 cop ratio. The smog motors were about 8.5 to 1. Whenever you lose compression u lose power.

[djgebert]

The heads you choose depend a lot on what you want to accomplish. A good set of Dart or World product heads will perform very nicely and make lots of power for most applications and they are fairly cheap. When you start getting into good aluminum heads the price goes way up. I see cheap aluminum no name heads on eBay with all kinds of spectacular claims, but I personally would never trust them. I bought a pair of GM fast burns used for under $1000 with only a few thousand miles on them and they make awesome power and will work with both newer and older style intake manifolds and valve covers. The 383 in my truck now is running forged flat tops with the fast burns and is around 11.3:1 compression, so not something you would want on pump gas. Your best bang for the buck to build a 383 is to buy a kit. You can get them already balanced, etc. The first thing you have to do is figure out what you want. Do you want a 400 hp street motor with great torque or do you want to light the tires at 40 mph. The higher the hp the more things are prone to breaking and the more you have to tune and tweak things. You can put together a 400 hp 383 that will run all day on pump gas and need no more maintenance than a stock engine.

[67 chevelle]

Originally Posted by djgebert

The heads you choose depend a lot on what you want to accomplish. A good set of Dart or World product heads will perform very nicely and make lots of power for most applications and they are fairly cheap. When you start getting into good aluminum heads the price goes way up. I see cheap aluminum no name heads on eBay with all kinds of spectacular claims, but I personally would never trust them. I bought a pair of GM fast burns used for under $1000 with only a few thousand miles on them and they make awesome power and will work with both newer and older style intake manifolds and valve covers. The 383 in my truck now is running forged flat tops with the fast burns and is around 11.3:1 compression, so not something you would want on pump gas. Your best bang for the buck to build a 383 is to buy a kit. You can get them already balanced, etc. The first thing you have to do is figure out what you want. Do you want a 400 hp street motor with great torque or do you want to light the tires at 40 mph. The higher the hp the more things are prone to breaking and the more you have to tune and tweak things. You can put together a 400 hp 383 that will run all day on pump gas and need no more maintenance than a stock engine.

I have run 3 sets of procomp heads , their weak point is their springs , replace them if you get procomp heads , we did have one fail , my favorite head for a performance street sbc is the dart sportsman , they have 200 cc runners , plenty for a 383 , and great components out of the box , the heads are where your power is made , and put a resonable cam in it , 268 is a good grind , alot of people ruin their build with too big a cam

[djgebert]

Before the last rebuild my 383 was running the Lunati 60103 and a set of dart sportsman heads. It ran great and had lots of power, I just wanted a lot more, lol. People don't realize the importance of all of the other components in an engine and drive train. You are right, the heads and cam are where the power is made, but people often don't factor in all the other components when they are building their engines. It will do no good for the OP to build a strong 383 unless it has good exhaust, good carb, better ignition system, u-joints, rear end gears, stall speed........ I cringe when I see people putting huge cams in a 9.0-1 compression engine with old 2.02 heads or $2000 aluminum heads on a tired 350with a small cam, it just makes no sense. I think most people don't really know what it is they really want and so they just start throwing parts together without a really good "blueprint" of what they want to accomplish and the individual parts needed to get to that point . If you don't plan it out first you will spend a lot of money that you don't need to and/or hate what you have when you are done.

[Old Truck Man]

I sell all the 400 crankshafts I get to guys who build 383,s. I keep the 400 block and use spacer bearings and install a standard 350 crankshaft. I like RPM and if you can turn more RPM than the other guy all else being equal you will out run him. I know of a guy who installs 283 crankshafts in 400 blocks. I researched it and Im pretty certain no 400 small block ever left the factory with a standard shift? The only externally balanced stick flywheels I ever found where for 454,s. A 454 flywheel wont balance properly on a 400.

[mrein3]

Originally Posted by haysonj

Go to Scat and buy the entire rotating assembly already ballanced. If you are careful you can clearance the block yourself with a dremal or die grinder You need about .050 where the rod bolts go by the rails and the bottom of the bores will need some touch up as well. The 400 crank is old school and not a good way to go.

For sure the way I did it was old school but it works fine. If I did another one I would buy a complete, balanced assembly. At the time I built mine however a used 400 crank was the most cost effective way to go.

I always tell people to price out a 350 rebuild then compare it to the cost of making that 350 a 383. There is very little difference.