I am almost ready to start assembly on my 383 stroker engine and i know a lot of people have to notch their block slightly to give extra space for crank/rods and I was wondering if anyone will have a "template" or something to follow on where to notch at and also what tools you used to do so. I have 6' rods for my engine which i heard will make it so i wont need to do as much clearancing but since this is the first engine I'm building I want the most information I can get. also if anyone has built their own 383 for a c4 and would be willing to private message me so that i can ask some more questions that would be awesome, I've got so many random questions that I feel wouldn't be fit for any of the forum pages.

 

There is no "generic" template for clearancing blocks. How much you need to remove depends on your rods and rod bolts and block.

 

..... Check with your nearest local performance machine shop ... find out who builds race engines in your area ... they can tell you what needs to be done ... as 383vett pointed out , it depends a lot on what parts that you intend to use ... block and rods .....

 

More important that the 6 inch rod is what type of rod bolt they use. Is it a cap screw or a through bolt? How much angle does the rod have at the top of the bolt area? Also be aware you may have some clearance problems with the cam to rod bolts which will require the use of a small base circle cam, depending on the above mentioned and the cam grind, more specifically the LSA.
You can take an old piston, wrap it around the skirt with duct tape to take up the slack for no rings, put it on the rod, and with some old rod bearings make a piston/rod for assembly on the crank. Then turn the crank to determine how much clearance you need and start grinding. Two of the eight are closer than others but I forget which ones. Good Luck

 

My last (and only) 383 needed very little clearancing on the oil pan rails and slight cleanup on the bottoms of the bores... mainly just casting flash there if I remember correctly. But that was an 880 block. You don't know until you have it in front of you. My machinest said it was one of the lesser ones he's done... and considering how many he did I was surprised. But a lot of that has to do with the rod.

 

Hi
My 383 build needed the usual clearancing at the sump rails and bottom of bores, to clear the rotating assembly and small rod bolts.
Some rotating assemblies come with rods and bolts for minimal clearancing, I did have core shift no3 cylinder water jacket. Even though I did the minimal clearancing there was a weep from the water jacket. Lucky I checked with water in the bare block, was easy to weld up.
Always check the block after clearancing, let it stand dry it and put some water in the water jackets.

Sometimes the crank may not clear the front or rear of block recesses, blue tac or similar helps to double check clearances.

paper towel is handy, rub over all areas that have been clearances and look carefully.
leave it overnight on an engine stand with paper on floor to show any drips.

Dont forget to thoroughly pressure wash the block, pay carefully attention to oil galleries.
wash and wash the block repeatedly, to get all the grit out.

Don't forget to test the sump clearances, i found a couple of spots that needed to be modified to clear the crank and rod bolts.

Rotate the assembled engine at minimum twice to check clearance to camshaft

Replace the oil filter especially on a clearanced engine after first 20 min run, I drained the oil removed sump and thoroughly cleaned it before refitting and using fresh running in oil.

Good luck, enjoy and dont worry too much striking a water jacket, should only happen if the core shifted in manufacturing is quite rare.
grind a little, check grind ,check and recheck you will need around 0.050" clearance minimum.
Some specify 0.030" to 0.080" if you have a machine shop nearby that does preprogrammed cnc clearancing it will keep your nerves in check.

Good luck with your build.
You will enjoy the extra torque, you will never look back.