Hey guys, I have been searching for about an hour on info for building a 383. I bought a lt-1 out of a 96 impala ss. Iron heads i know i know. Anyway its going into a 95 Yukon with 11" lift rolling 40" tires. I need as much pickup as I can get but nothing that will hurt the mileage. I ripped the intake and the heads off and got a good glimpse of the cylinders, they have the normal grit from sitting to long without being ran. The engine is very low miles and the top end is in exellent condition. I plan on having the cylinder bored and honed .030 over with new pistons. But while I was at it I was thinking about going to a 383.

What all is going to be neccessary. I see most people use scat 9000 cranks. Besides that and hi beams, what else will I have to do to make this run strong and last a long time, also, is this going to hurt mileage?

 

I suggest headers and an LT4 hot cam. The LT4 will give you more torque and HP, without being high rpm peaky, or lopey.

 

I have a Scat 9000 crank, Triton rods, and SRP forged flat top pistons. You might want to look at getting a set of aluminum heads off of an f-body and have them ported. If you do go that route, you'll need a matching cam to get the full potential out of the heads. Most of your power comes from your heads/cam combination. If you go with a stroker bottom end, but leave the heads and cam stock you'll have a little more power versus the stock bottom end. It'll be nothing like the power difference with a set of well ported heads and nice cam. Just like with most performance modifications, you will loose gas mileage. I get somewhere in the neighborhood of 15mpg city and 21mpg highway if I keep my foot out of it. I would recommend speaking with a local machine shop that you know does good work and see what kind of parts and prices they can give you. Good luck with it.

 

Your going to lose a few MPG with a 383. Bigger motor just takes more gas to use.

Other than the Iron heads weighing a ton they are great flowing heads and extremely durable. Plus you can get a 2.02 intake valve in them without a problem. If you are on a budget just get them ported and polished. Here are my ported iron heads I just bought.

http://www.jbelectric.us/ot/ImpalaSS/heads/

Additional items need for a 383

Single piece rear seal 3.75 crank. Scats 9000 are cheap and great
6.0 or 5.7 inch rods (The 6.0 rods are said to make more torque)

Some .030 piston and rings

You will also need to get the block clearance for the crank, and depending on what rod you run you will have to clearance the rod bolts for the cam.


ARP main stud kit and a bucnh of other little things. Do a search for 383 and it should bring up everything you need to know

 

I have been told that I can use my stock rods, is this true? I plan on keeping the iron heads, how much is a porting? and am I going to need anything else with that?

 

Ya stock rods will work fine. Just throw some ARP rod bolts on them.

Porting depends on who ports them and to what degree they are ported. Could be anywhere from $500-$2000.
http://www.cmotorsports.com does good work, along with Llyod Elliot (dunno if he does Iron heads thou). Or a good local porter shouldn't have any problems.

 

So check this over before I start spending the cash. I'm getting my cylinders bored to .030 over with new flat top pistons and piston rings. SCAT 9000 400 crankshaft, and im going to go with a mild cam, is there anything else needed? Besides the bolts for the rods like you said.

 

You want to make sure the crank is for a 1 piece rear seal or else you have to run an adapter

New oil pump
Timing Chain
ARP Main stud kit
Lots of gaskets
ARP 3/8 rocker studs
Main and rod bearings

and I am sure lots of other little stuff I cant remember right now.

 

I know about the rods and main bearings, do I really need the oil pump and a new timing chain?

 

Opps, forgot cam bearings and freeze plugs.

A new timing chain is less than $20. Might as well replace it.
A new oil pump is cheap insurance, expecially if you plan on reving the motor a bit. Even thou most guys on this site hate high volume high pressure pumps, I went for a morso high volume high pressure blue printed pump.

http://www.jbelectric.us/ot/ImpalaSS...osooilpump.jpg

 

Ok, doesnt sound as much as I though it was going to be. What kind of horsepower gains/ tq gains am I looking at by doing the new crankshaft?

 

TTT

 

The main stud kit and rocker studs aren't necessary. However, I would definately go with a new oil pump and timing set(chain and both gears, not just chain). You might as well leave the old chain on if you're going to run the old gears. As mentioned, make sure you get the Scat 9000 3.75" stroke crank for one piece rear main. You'll also have to either leave off, modify, or get a new windage tray with the increased stroke.

Another thing, I would have the rods checked by a machine shop and get ARP rod bolts.

 

I would definately get a main stud kit. Also i would highly recommend using a set of forged i beam rods instead of stock.

 

Thanks guys for all your help, as of right now I only have enough money to bore the cylinder to clean them up with new pistons and rings. But I would definatly like to add a cam, but keep my stock valve springs and rockers. Is there any cam out there for me? Remember I'm looking for low end to pull these big tires.