Guru_4_hire

Does a 383 require notching the block?

gkull

You have to grind clearancing for the rod bolts on a few of the forward cylinder pan rails. You really can't determine this until you get the rotating assembly installed


Years ago I used 6.125 H beam rods in a 350. It required grinding the bottom of the cylinders for beam clearance

For my other small block I had to grind the rod beams for the cam lobes to clear the rods

The last two are extreeme examples

Guru_4_hire

So rods profiled for stroker clearence should be OK?

Gordonm

No. My rods were stroker rods. I had to clearance the block in a number of places. I did not grind anything on the rod. All blocks will require something a little different. Get your rotating assembly and trial fit everything and check clearance at least 3 times in all locations.

Bee Jay

Hi Gordon, did you do the clearancing yourself, or did you have your machine shop do it? I understand it's easy to hit water.

blctalon

The machine shop I used clearanced the block and told me it should be enough. When I put the lower end together and spun everything around I found that it wasn't enough. Luckily, what the machine shop had done was 80% of the work in the right spot. All I had to do was get a dremel stone and open it more to my liking. Some places were as tight as 15-20 thousandths, I opened my clearanes to at least 50-70.

I, however, am building a sbc 406 so where you stand with the 383 might be different. The concept is the same as mentioned above. Trial fit everything before you torque all your stuff down to specs and spin it around to see where you are. I had to tear mine down 2 times after I got it back from the machine shop to make it how I wanted it.

I am using Eagle H-beam forged rods. The rod you're using could make a difference.

Don't get frustrated if it doesn't all go together the first time.

Gordonm

I did all the clearancing myself. There is a good amount of meat there just don't get overzealous with the grinder. Just grind some and check. I must have had the crank and rods in and out 4 or 5 times per cylinder. It took me about 3 to 4 hours to get it all done.

79VetteMike

It depends on what rods you are using. The stroker rods you are talking about are probably clearanced for the cam, not the block. Different rods have the bolt sit at different heights. I am using Summit(Scat I think) I beams with cap bolts. I had to grind a decent amount. On the Eagle H beams I have, the cap bolt sits higher, so they would require more clearancing, which is why I am worried when it comes to clearancing for my 396 small block.

79VetteMike

I forgot to ask, did you get your heads back yet?

ratflinger

79VetteMike, I too am building a 396. I started with a GM clearanced block that is the basis for the ZZ383. GM clearanced it for their 3.800 crank. Eagle claims that the the 396 kit (3.875) will fit with no more clearancing. We'll see, this block & kit go to the machine shop tomorrow, as the machine shop wanted to custom bore the block to match the pistons, instead of a standard .030 over bore.

79VetteMike

I tend to ramble sometimes, so I might be confusing to some. The I beams I am using for my 3.75 stroker in my 1970 Monte Carlo. The 396 is for the Vette-if I ever get it together. I am taking a break right now as a matter of fact from the 377(3.75 stroke, New GM 4.00 block). I'm putting my heads together right now.

P.S. Have a part number for that ZZ383 block?

ratflinger

GM pn 88962516

Guru_4_hire

no :

Apparently last week the porting guy's wife was in the hospital. I am not sure if I am getting the run around or if the guy is just unfortunate. The results of their racing vacation that they couldnt do it the week before was positive. They did really well. I am going to give a call today. I did tell them there was no rush when I dropped all the stuff off, and they are swamped with a dozen hot cars. Walking into their shop is half a car show. It really is neat. I will get irritated depending on how much they charge me.

gkull

Don't worry be happy! I have not hit water yet Even if you did, the quick fix is dump some epoxy in the water jacket and just fill the lower 1/3. You then end up with a more ridged block that has better cooling. In past years I also aquired an "X " 360 sprint car racing block that had been sleeved

SanDiegoPaul

I used a SCAT rotating assembly with 6" H-beam rods. I had to notch the cylinders as well as underneath the cam bosses ...

79VetteMike

Hey Guru,
I posted some pics of my heads that I ported and polished in a thread about my 1970 Monte Carlo project.

bluegtp

I have a cast 383 scat crank....block is at the machine shop getting bored 30over.....when i get it back I will start test fitting everything.....I've heard some don't have to touch much and some have to do some work!...

ryan

682XLR8

I did my clearancing with a carbide cutter and die grinder. I had to clear the pan rail and bottom of each cylinder, as well as grind a small area of my stroker rods to clear the high lift cam I'm using. It took several hours to get it all done, most of the time spent is assembly/disassembly, only a few minutes to do any actual grinding. I used pistons that came with the block for the set-up(easy if you're using floating pins), when all the grinding was done I sent the block to the shop for boring/cleaning

mandm1200

From what I read when I did mine is that .060" clearance is needed. I had to clearance the bottom off many of the cylinder walls and a few spots on the oil pan rail. I had no idea as to how thick the material was so I only ground of a little at a time. Since I was working with a new parts, the parts were installed and the area marked for clearancing. I used a dremel to grind the areas which I marked with a marker. The blocked then had to be washed of the grindings and everything test fitted. After about 6 tries I felt I had the clearance needed. If you have old bearings, it would make things goes much faster because the cleaning part of the process would be eliminated. The rod bolts to cam also have to checked. Typically there are two that will cause a problem. The machine shop I bought the rotating assembly from 'clipped' the ones which may cause a problem prior to balancing. It is very tough to get a feeler gauge to measure this. This is not a precise measurement. It a 'go' or 'no go' measurement. Find something flexable about .060" thick to get in there. As long as you are close to .060" you are fine.