0.060 Over

[RVT1000R]

Does anyone know what the approximate cid of a 350 boared 60 over? Just wandering, got a call today form the guy that is working on my block. He said that it was allready 40 over but that it was not even so I said punch it out to 60 over!! Also what would I need to do to make her a 383 stroker? I have to get a crank anyway my stock one was shot. Keep in mind that I would like to keep the price down by using the stock connecting rods. So if there is any one who needs a set of bran new std size pistons let me know they are made by Sealed Power. Thanks guys

[gmcman7202]

dont use the stock rods, youll regret it later

[QKENUF4U]

supposedly every .030 = 5ci
youll need a 400 crank in your 350. they make 383 kits all day long with everything you need.
just use your search button and look up "383 crank kits" and youll find lots of options.

[BarryB]

Every .030 over bore adds 5 c.i.'s So you will have a 360 ci. In order to make a stroker. you need a 400 crank, 350 rods. And special stroker pistons. 400 harmonic balancer and flywheel. Or you could buy a stroker kit from summit it has everything you need. You will also have to have the inside of the block clearanced for the stroker crank and such.After you get everthing clearanced , you will need to have the assembly balanced. There is quite a bit of machine work to be done to make a stroker motor, but it is well worth the effort.

[gmcman7202]

i was goning to do the 400 crank in the 350 but they wanted about 1500 just for the maching that needed to be done. so i just went with the 400.... very happy with it.

[passthebuck]

My 327 bored 60 over = 336cui

[shane72_383]

Originally Posted by BarryB

Every .030 over bore adds 5 c.i.'s So you will have a 360 ci. In order to make a stroker. you need a 400 crank, 350 rods. And special stroker pistons. 400 harmonic balancer and flywheel. Or you could buy a stroker kit from summit it has everything you need. You will also have to have the inside of the block clearanced for the stroker crank and such.After you get everthing clearanced , you will need to have the assembly balanced. There is quite a bit of machine work to be done to make a stroker motor, but it is well worth the effort.

You use 400 crank and rods not 350 rods.

[Ole Blue 68]

I might be wrong here but I thought a 383 used a 350 block bored .030 (355CID). If you bore your block out to .060, you're not going to wind up with a 383. You'd have a 388...I think.

[FRENCHBLUE72]

P.A.W. sells a great kit for the stroker set-up..

[19673ontree]

stock 327 = 4'' bore 3.250'' stroke
stock 350 = 4'' bore 3.5'' stroke
stock 302 = 4'' bore 3'' stroke
stock 400 = 4.250 bore 3.750 stroke

stroker 350 block 4'' bore 400 3.750 crank = 383
stroker 400 block 4.250 bore 350 crank 3.5'' = 372

isn't the interchangeability of the now non existant general motors part's wonderfull !!

[glock35ipsc]

Bore x Bore x .7854 x Stroke x Number of Cylinders = Cubic Inch Displacement

Stock 350 = 4.000" bore, 3.48" stroke
Stock 400 = 4.125" bore, 3.75" stroke

Stock 350 = 4.000 x 4.000 x .7854 x 3.48 x 8 = 349.84857 cid
.030" over 355 = 4.030 x 4.030 x .7854 x 3.48 x 8 = 355.11597 cid
.060" over 360 = 4.060 x 4.060 x .7854 x 3.48 x 8 = 360.42274 cid

383 = 4.030 x 4.030 x .7854 x 3.75 x 8 = 382.66808 (350 block .030 over, 400 crank)
388 = 4.060 x 4.060 x .7854 x 3.75 x 8 = 388.38656 (350 block .060 over, 400 crank)

377 = 4.155 x 4.155 x .7854 x 3.48 x 8 = 377.48715 (400 block .030 over, 350 crank)
383 = 4.185 x 4.185 x .7854 x 3.48 x 8 = 382.95791 (400 block .060 over, 350 crank)

The most common 383 is a 350 block, .030" over with a 400 crank that has the mains turned down. It can be done with a .060" over 400 block and 350 crank with oversized bearings, but the 350 block is the best way to go. That, and I wouldn't take a 400 to .060" over, cylinders are too thin and overheating can be a problem.

*** I've had to correct my math a few times, so if you thought I was stoned, just refresh the page

[RVT1000R]

Well guys thanks for the info it has helped! Now if I want to run a 3.75" stroke crank will I have to do something to the block? which is better 5.7" or 6" rods? Is it better to go internaly balanced or externaly balanced?

[glock35ipsc]

The block will have to be releived for the 400 crank to clear the block in a few areas, near the pan gasket surface and some cylinder bottoms. If it is a street motor, 5.7" rods will do just fine. If you are going to put it on the track too, then look at 6" rods cause the 6" rods usually will set the wrist pin in the oil ring. Just be sure the pistons are correct for the rod length!!

I would go internal balance. And use a Scat crank! Bomb proof!

[gmcman7202]

both ballanced works best
think about it... its a rotating mass, if it is all ballanced, it will be the best in the end

[glock35ipsc]

Stock 400's are externally balanced. All other SBC are internally balanced.

[wolfthing2000]

Don't bother mocheeenin that 400 crank, just buy a 383 crank. If they told you 1500, then think about the whole picture. Was it cast or forged crank and pistons?? Bore and line hone hone mains??? Deck Bore and hone for oversize pistons, balance the whole schmear and grind for clearance measure this and that assemble diss-assemble and do it over again, make sure it doesn't smack the cam . the block, the pan new hardware, balancer clean it oil it and on and on and on and on......
1500 for the bottom end ain't too bad!!
Mine cost 3 gs and I got everything from the shop except my bare heads!!! They did it all so I put the other 1500 into all of the assembly and parts etc. to put oversize valves in and a full roller valve train

1500 is a good price for a 383 bottom end.

[junkyardjohn]

I AGREE.. THAT IS ALOT OF HOURS OF LABOR. IT DOESN'T TAKE LONG TO ADD UP TO $1500. JOHN

[sleepyboy]

Not to steal the thread but I had two relevant questions? I had a 350 bored one time and the guy told me NOT to go .60 over because it makes the walls too thin? He said go no more than .30. Is that B.S.? Secondly, What is the big deal with a stroker motor?

[mrein3]

Originally Posted by sleepyboy

Not to steal the thread but I had two relevant questions? I had a 350 bored one time and the guy told me NOT to go .60 over because it makes the walls too thin? He said go no more than .30. Is that B.S.? Secondly, What is the big deal with a stroker motor?

You can get big block LIKE performance out of a small block engine. Notice I said LIKE. There is nothing like a big block except a big block. With a "stroker" you get a longer stroke. This give you more torque over a stock engine.

If you are just going to drive your truck around like a truck you can use a stock 400 crank and stock 350 rods. Have a competent machine shop go over both. They sell pistons with the wrist pin higher up in the piston to work with a stock 400 crank and stock 350 rods.

If you want a crazy fast, blown, NOS, or some other wild application, look for something stronger (aftermarket) for the bottom end of the engine.

I have 2 years and 2000 miles on my 383. I built it with a 1971 Monte Carlo 2-bolt 350, bored .030 over. The 400 crank was on the machine shop guy's shelf. The rods were out of the 71 Monte.

I expect to get 100,000 miles out of this engine. At the rate I'm going it will last 98 more years.

If you are at the point in your truck's restoration that you need to rebuild that tired old 350, and you don't need a big block, the 383 is the ONLY way to go.

[glock35ipsc]

.060" over on a 350 is acceptable, but the cylinder walls of a 400 are much thinner due to the larger bore (4.000" for a 350 -vs- 4.125" for a 400). I have built many, many .060" over 350 street motors without any overheating problems. I have also screwed together a couple .060" 400's with no problems, but I would stay away from going that big on a 400 if at all possible.

[wolfthing2000]

Don't mess around with the 400 crank since it has to be resized (machine work$$$$$$!!!!!) and you can buy a 383 crank for much less.

[wolfthing2000]

The big deal with strokers........................................:::::::::::::: Stroker=Stump Puller!!!!!!

[glock35ipsc]

Hmmm, I guess it depends on the machine shop. Mine never charged any different for turning down the 400 mains to fit the 350 block, as he would charge for turning any other crank. Same price to machine the journals no matter how much was removed......

[junkyardjohn]

When In Doubt About The Wall Thickness.. Have It Sonic Tested At The Same Time You Have It Magna-fluxed To Check For Cracks. Theres Always A Possibility Of Striking Water Due To "core Shift" During The Original Casting Process. Hasn't Happened To Me Yet. (knock On Wood) John

[Ole Blue 68]

Originally Posted by sleepyboy

Not to steal the thread but I had two relevant questions? I had a 350 bored one time and the guy told me NOT to go .60 over because it makes the walls too thin? He said go no more than .30. Is that B.S.? Secondly, What is the big deal with a stroker motor?

I think the machinist was giving you good advice. Suppose you had to have the block machined again? You'd still have room to work with a .030 while a .060 wouldn't leave you much at all and you'd probably be shopping for a new block.