Can a '63 327 be turned into a 383?
 

I am looking at my options for a motor and I had a crazy idea of taking the original motor and turning it from a 327 to a 383 stroker. Can that be done, what internal modifications have to be done?

thanks, Herb

Yes you can but you are going to spend a lot of money to do it. Might be easier to just buy a 383 crate motor. :thumbs:

The mains of the 400 crank are much larger than your small journal block. You need to plow the 400 crank down around .200 to fit a 350 large journal block.

Interesting thought, and it depends on how much money you are willing to spend. Grinding a stock 400 crank around .400 under on the mains is risky, not so much for finished size as the problems that will surface with the oil holes in the mains.

If you get a crank made, you can do it easy.

Do a search. "Tom Parsons". He's gone through it a couple times. I think somebody mentioned CrankShaft Company in Calif. was making a kit.

the reason to do it would be to keep a numbers matching motor with the car.....

If you have a numbers matching motor, I would not make it into something it isn't. I would put it aside in a corner of the garage and save it. Then buy a 383 crate for driving. Unless you are going to be judged. That is a different situation and then I see your point. :thumbs:

the only reason to keep the motor is if I was going to put it in the car. There will be nothing under the body that will be stock. SRIII frame with 5 or 6 speed with Dana 44 rear end...the only thing to do now is to consider the motor....

Perhaps a different way to go with the motor is to build it into a 9000 rpm beast....otherwise my options are LS3 with supercharger OR LS3 with twin turbos OR LS9.....I need to make up my mind in the next few weeks and this was an option that I thought about today.....otherwise I will sell the motor and rolling chassis.....

OK, I am NOT going to make any judgements or recommendations about what you should or should not do, regardless of matching, non matching, crate or whatever motor.
All I'm going to do is ONLY answer your question with various ways that you can convert a small journa 327 into a 383.

First, a 383 is a .030 over 4in bore block with a 3.75in stroke crank (same as SB400 crank).
The MOST common and popular method is to use a 350 block (ALLLLLLLLLLLLLLLLLL 350s are big journal versions), bore it .030 over and install a 3.75in stroke crank with 2.45in main journals.
The EXACT same thing is done with a SJ 327, but with a couple of variations.
To stroke a 350 to 383, you either buy an aftermarket crank that already has the 3.45in mains, or, locate a serviceable SB400 crank and have your machinist turn the 400 mains down to 350 size. That's the first thing.
The next thing is to grind clearance notches at the bottom of each cylinder for rod clearance (SB400 blocks are cast with these notches). You need to be careful when grinding these clearance notches so that you don't grind too deep and go into the water jacket. It's not a big deal to do this, just time consuming and tedious. It needs to be done one cylinder at a time with the crank installed in the block and a rod on each journal to check for adequate clearance (.010-.020in clearance is adequate). You can do this yourself at home with the block/crank on an engine stand (I personally do all this kind of stuff myself), or you can pay the machine shop to do it. Either way, it will have to be done. Again, no big deal.
The larger 350 5.7in rods should be used. Consequently, the heads of the rod bolts that face the camshaft will need to be slightly clearanced (at about a 45deg angle) to clear the cam lobes. USUALLY, there are only about 2-4 rods that need to have the bolt heads clearanced, but it is just much more simple to go ahead and do all 8 and eliminate any guess work. An option to clearancing the heads of the rod bolts is to buy aftermarket rods which have cap screws instead of bolts/nuts.
So far, all of the above will be the same for either making a 350 block into a 383 or a 327 into a 383.

Now, to be more specific for the SJ 327.
There are 2 options for the crank. Either one will require a slight reduction in the diameter of the flange of the crank that is BETWEEN the rear main bearing and the rear seal journals. The groove in a 327 block for this flange is slightly smaller than the groove in a 350 or 400 block. Thus, the need to slightly machind the OD of this flange------------------NOT THE THRUST SURFACE, JUST THE OD!
You CAN buy a 3.75in stroke for a SJ 327, then just build it up the same as would be done building a 383 from a 350 block.
Again, you can locate a serviceable 400 crank and have the machine shop turn down the mains to 2.30in (small journal main size).

Last, and I like this method better, but, it costs somewhat more.
FIRST, Have the SJ 327 main bores line bored to large journal 350 size.
Next, this will require NEW notches to be cut into BOTH the block and the main caps for the bearing tangs. THE NOTCHES FOR BEARING TANGS OF 350 BEARINGS ARE IN A DIFFERENT POSITION FROM SMALL JOURNAL 327 BEARING TANGS. A good machine shop that is familiar with doing custom machine work can do this, but it may be a good idea to point out the fact that the 350 bearing tang notches are located differently than the 327 notches!!!!!
Have the machine shop tap the holes for the main cap bolts deeper and use the longer 350 main cap bolts.
Now, you have a SJ 327 block bored out to 350 main journal size. You can now use (either buy aftermarket of have a 400 crank machined) a 3.75in stroke crank with 2.45in mains (350 size) instead of the smaller 2.30in mains.
With this last method, you have converted a SJ 327 block to the equivalent of a LJ 350 block. Now you use a 3.75 stroke crank with the 2.45in mains, turn down the flange at the rear as mentioned earlier, grind clearance notches at the bottom of the cylinders and build it up just as you would do when building a 383 from a 350 block.

Is there any benefit to doing any of this from a 327 block?
Well, that is totally dependant on your point of view. IF, IF, IF you have a big desire to retain NO-HOLE valve covers (such as the finned alum versions with the Corvette script) and also have a block with the hole in the rear for crankcase ventilation, then this will do the trick!!!!

There are still 2 more options to consider.
1. It isn't matching number, but it will allow you to keep the NO-HOLE valve covers and have a crankcase hole in the rear of the block.
THE 1967 ONLY SS350 CAMAROS had a large journal 350 block with the vent hole in the rear. There were also some REPLACEMENT blocks from the parts dept that had big journals and rear vent holes. If you could locat one of these, then you would just need to obtain a 3.75 stroke crank with the 2.45 mains (or have a 400 crank machined) and then build your 383.

2. Instead of going out to a 383, stroke your 327 SJ block to 350. This is the easiest and cheapest way to gain displacement from a SJ 327 bolck. Simply locate a serviceable 350 crank (or buy one) and have the mains turned down to SJ size (2.3in), and have the OD of the rear flange turned down to fit the groove in the 327 block. Use the larger 350 rods and build it just as you would build a very healthy 350. No need to clearance the rod bolt heads or cut clearance notches in the bottom of the cylinders.
That's the options that I know of for increasing displacement of a SJ327. I've personally built some of the above, or, my machinist and I have gone over what has to be done to build them.

Herb
A buddy of mine builds all of his own motors for his vettes and drag cars. He has built a number of 383 motors from 327 blocks. In fact the last motor he had in his '65 was a 383 he built from a 327 block and dressed it up to look like a "correct" L76 motor with the correct L76 intake, exhaust manifolds, 2818 carb, etc.

sure, using stock parts like the exhaust manifolds, etc he sacrificed some power but he liked having it look stock but having a LOT more power than the stock motor would have given him.

On the other hand, I have another friend that used to build race motors for a living and he has also built 327's into 383's but doesn't recommend it. He sent me an email about this subject 3 years ago and this is what he said (thanks for the info Bill):

"Converting any 327 block, particularly the early (pre-67) blocks to a 383 is both difficult and expensive.

We did a friends 327 using an Eagle 383 stroker kit (about $1600). First, they don't make a small journal (2.30 inch) crankshaft which means you have to either turn down the main bearing journals from medium (2.45 inch or what most call large journal and are not) to small journal size or line bore the block to accept the medium journal size crankshaft.

Secondly, the amount of cleanancing or relieving that must be done to the bottom end of the motor is extensive. This must be done so the connecting rod bolts will clear the lower end of the cylinders. You also have to relieve the pan rail for the larger counterweights if the crankshaft is internally balanced. Some use a 400 ci crank but these are externally balanced so the harmonic balancer and flywheel have to be changed as well.

In the process of relieving the block we started with, which was a 64 327 block, we ended up grinding through the cylinder wall to the water jacket, thus ruining the block. Early blocks were subject to what is called core shift. This is where the blank for the cylinder location in the sand mold moved during mold packing and the cylinders are not true center to center. Core shift can cause premature cylinder wall break through when relieving and also cause really thin cylinder walls when boring the cylinders to larger than 0.030 oversize.

Eagle wants 0.040 inch clearance but this results in what happened to the first block.

The second block which was successful was a 67 block. In anticipation of the 350 motors being produced, a slight change was made to the lower end and some small relief was cast into the block. Even so, some significant grinding had to be done to clear the Eagle H-beam rods and rod bolts. We stopped relieving when we had a good 0.020 where the rod bolt clears the ground out sections of the lower parts of the cylinder.

Personally, I wouldn't risk another block to do this again. You can get almost as much from a 355 which is a 0.030 overbore 327 with a 350 crank that requires very little work. Just turn down the mains to small journal size and do a little work on the bottom end and all is good."

Tom has given you all the info you need so there isn't any more worth saying on that part.


However, regardless of what condition the car is, all those parts can be redone or replaced to original someday if you, your kids, the next (or the 50th) buyer after you decides to.

There is only one original engine, and odds are if you are going to a 383, then some day you will put enough power to it to break it.

If everything else is changed, then there is no reason to pretend the engine is just all original and stock. Drop a crate engine in and be done, plus buying from the right places gets you a warranty.

You building one from yours won't.

I'd like to say that I agree. Set the 327 aside if you want the feel of a BB in small block form and get a 350 to 383 motor. My 327 in my 67 sat a long time and was a real smoker. All the good machine shops were busy when i wanted to do it ( race motor season). So i put a stroked block 383 and added aluminum heads. Wow what a great car it is now. Still light on it's feet but gobs of torque. The car pulls at any RPM great! I've had a few BB's and this is a much nicer set up I think it's as fast and I know it handles much better without all that real BB weight up front. My first 383 and I am a absolute Fan.

Now, with everything that's been said, and all the replies that have been made, here is my personal input for big time power/torque in a small block configuration.
With the following, you will have to use valve covers with holes, OR, you will have to somehow drill/machine/locate a hole SOMEWHERE (such as in the rear of the intake manifold) for the installation of a PCV valve. YOU GOTTA VENT THE CRANKCASE SOMEHOW!
The ultimate small block is of course, is a SB400. A .030 over SB400 gets you 406, and with a STOCK GM block, it is fairly easy to get one up into the 420-427 range. You CAN get to 434 with a stock block----------------------but for a DRIVER, those scare me. To begin with, the SB400 has already been pushed to just beyond its design envelope. And to extract even more displacement from a SB400 is walking a thin line so to speak. BUUUUUUUUUUUUUUUT, so what, it's only money.
Anyway, the SB400 is my favorite (for a SB that is).
So, where I'm going with this, is if you're going to spend good money on a strong SB, the cost of building a VERY nice SB400 really won't be that much more than building a 383-------------------ESPECIALLY building a 383 from a SJ327 block. You can jump out there and buy top of the line aftermarket free flowing heads, or just some nice aftermarket heads that will outflow ANY stock head ever made, or, you can take a set of GOOD 1.94 or 2.02 cores, have them machined for a set of 2.02 (or even 2.05)/1.6 stainless valves (DON'T WASTE YOUR MONEY TO HAVE HARD EXHAUST SEATS INSTALLED), have some port/bowl work done on them, drill the steam holes and bolt them right on to a 400 block and retain somewhat of a stock appearance. Install a NICE hyd roller cam, bolt on your stock oil pan, timing cover with a tab for an 8in balancer, use the UNbalanced 400 balancer (ya, ya, people will notice the 400 balancer, so what) and flywheel, bolt on a stock alum manifold with a hole in the rear for a PCV valve, bolt on 2 1/2in ex manifolds with a VERY free flowing 2 1/2in ex system and enjoy.
I have a SB400 in the 56, and there is no way I'd consider going back to a 265-283-350 size engine. Not even if someone walked up to me and GAVE me the original, numbers matching 2x4 265 that St. Louis installed in it. :nono:

As the saying goes: There is no replacement for displacement! :thumbs:

Longer rods!
 

Tom has it right, the only thing I would add is use longer rods, 6 inch rod 400s are a thing of beauty. You need rods anyway and pistons and I think you will find it easy to get all the parts as these motors are very popular.

If somebody had a '63 a few serial numbers before or after his car, built the same day, could experts tell if his engine was not original to their car?

As long as he's building a rod, he might get more than the price of that new 383 from someone trying to go stock original.

Tom...., why are "hard exhaust seats" a waste of money ? I did not have it done on my double humps only because I forgot to tell the machine shop. I've been using CD-2 Lead Substitute ever since. Am I wasting money on the CD-2 additive ? Thanks...............

The cast iron seats work harden very quickly. When some leaded fuel is used during a new engine run, that lead is quickly worked into the cast iron. You also run the risk of the heads cracking between the seats. I wouldn't bother with any additives. In addtion, testing by GM has shown that hardened seats aren't needed for general use, they do benefit heavy duty use.

Jim'
Your question has been pretty much been answered by Scott.
"Back when" (probably before you were born), when the lead in gasoline went away, there was LOTS and LOTS to do made about "older" engines not being able to tolerate the unleaded gas in the areas of valves/seats/guides. Thus, it was determined there were 2 ways to deal with valve seat recession (PRIMARILY the exhaust valve seats). Were these scare tactics to get the older cars off of the roads and replace them with new cars????????????? Who the heck knows (but it sounds good)! Anyway, you could either buy lead additives to pour into your gas tank which would boost octane rating as well as provide protection to the valves/seats/guides. OR, you could yank the heads, have them reworked, install new stainless valves and have the seats milled to accept a special hardened steel seat material that was resistant to wear. LOTS of lead additives have since been sold. LOTS of heads have had hardened seats installed. Everytime I had an engine built, I had my machine shop install hard ex seats. To do this, of course requires making a rather deep cut into the seat area for installing the new seat. On ocassion, this cut has resulted in penetrating the water jacket. The head is now junk. Fortunately, all of the heads that I have had seats installed in are still just fine.
After about 20-30yrs of experience with unleaded gas in general purpose, older engines that DID NOT have hard seats, more and more evidence surfaced that unleaded gas WAS NOT causing significant (if any) valve seat wear (over and above normal wear)!!!!!!!!!!!!!!!! :eek:
Consequently, many people in the auto engine fields (machinists, rebuilders, enthusiasts, etc, etc) began to take a second look at and reassess the added value of installing hard seats in GENERAL USE gasoline auto engines, including this guy right here!!!!!!!!
The oldest surviving engine at my house, is the 350 in my 51 Chevy that I built in 1976 and at that time DID NOT have hard seats installed in the 461 heads. Several months ago, the left steel shim head gasket developed a water leak into #7 cylinder. So, I pulled the head, scrubbed off the cyl deck, took the head to my machinist and had him tear it down, magnaflux it, check it out and put it back together. HE DID NOT DO A VALVE JOB ON IT, just put in new seals and put all the valves, springs and retainers back in it and handed it to me for a VERY minimal fee. Got a new steel shim gasket, put the head back on, used LOTS of sealant on the threads of the same head bolts, buttoned it all back together, and have been driving it everyday again as my daily driver. How many miles are on that 350 that I built 32yrs ago WITHOUT hard seats???????? I don't have a clue, but it's been 32yrs worth of daily driving with unleaded gas and no lead additives and it didn't need a valve job after 32yrs.
I ain't havin no more hard seats put into any of my engines from now on! :thumbs:

Now, for industrial, heavy duty service (such as big trucks), continuous service or somethin like at, excessive valve seat wear in unleaded gas engines may be a problem. But I ain't got none of them kinds of engins! :D

Tom and Scott,

Thanks for your candid info. Couple of facts I forgot to include, not that it may make a difference. When the motor went together in 1989-90 I had the machine shop put in bigger valves (2.02 intake and ??? exhaust) and screw in studs as a treat. If there was any lead in the metal it may have been cut out during that process. Plus......, I've never run leaded fuel in this motor as it hasn't been available since the rebuild so I'm not sure how any lead would be able to get "worked into the cast iron" . And if none did...., am I at risk ? Although the motor was rebuilt close to twenty years ago I've only put about 10K miles on it. Mostly back road cruising with a couple of times at the track and some beat runs on the street.

Oh ya....., I remember leaded gas although it was being phased out when I started driving way back when. I turned 49 earlier this month !! Should I get some "Real Lead" and run in a few tanks of unleaded to work into the cast iron ??

Again..., thanks for your info.

Two answers.

No, it would not hurt a thing to run some lead additive through a few tanks.

BUT, it may or may not provide any added protection from future wear. For sure, what it WOULD provide, is added peace of mind for you. And for that reason alone, I would favor a little addition of lead as opposed to not adding it. So, put some in a few tank fulls. :D

A couple different book sources also suggest avoiding early blocks for this reason, 1969 and later blocks have beefier main webs and better radiusing for added strength also.

The only drawback to a later block is no road draft tube boss, if you want to fool somebody.



Doug