Vettrocious

Well, we're off... Going to build a 383 from this large journal 657 block...I'll need plenty of help with this one, haven't built a complete engine since 1969...a big learning experience, wish me luck

Mike

68hemi

Don't know what your intentions are regarding what you want from it or how you want it to look but here is a link to the specs on my build. You might want a different cam as mine was custom ground for my dual quads and 2 1/2" factory exhaust manifolds rather than headers. If you are going to run headers then there are many off the shelf cams you can use.

If you are going for a stealth factory looking 383 I would be looking at the new Trick Flow aluminum heads that have the total factory look.

https://www.corvetteforum.com/forums...383-specs.html

Mossy66

I'm going down the same path.


Gerry

Vettrocious

Thanks, I am going with the Trick Flow aluminum heads.

I read up on the stroking, GearheadJoe wrote a great article in the Corvette Restorer on that. Gonna get in touch this week with Scat about a crank, rods, and pistons, so I can get started with clearancing the block.

Be a while before I get to the cam. My intent now is to go hydraulic, with 327-350 type characteristics, but revised for the increase in cubes. Not sure who to use for that, but the fuel injection system is from Comp Cams, so maybe they're the right choice.

Gotta learn more about bearings, any suggestions for a resource would be great.

Thanks,

Mike

DucatiDon

You can search for my 383 build as well.

runs amazing!

Tcheairs38655

I'll be happy to provide you with the specs on my 425hp RHS 383 Magnum Stroker installed in a 66 convertible. I have volumes of info including tuning, jetting (600 holley) and testing. My car does have a sport suspension however, Hedman coated headers and side pipes. Puts big blocks in the shade. BTW, this engine requires a BB hood in my installation and NO wing nut on air cleaner.

DZAUTO

Are you going to go with the small journal size mains, or are you going to line bore the mains for the large journal main bearings?
And, are you going to modify the holes in the block for the main cap bolts and use the longer style 350 main bolts (or studs)?
With the exception of the last two small blocks that I have built (SB400s), I have always gone with a flat tappet cam. And I have always known that the ultimate cam is a roller (a hyd roller is just fine for the street), but they are 2-3times more expensive than a flat tappet cam.
Well, the last two engines I built got hyd roller cams. DAMN!!!!!!!!!! what a difference!!!! From now on I'm going to bite the bullet and install a roller cam!

Oh ya, the last Scat crank I bought had to have BOTH the main and rod journals turned by my machinist because the journals were NOT straight, they were tapered!!!! And he said it is sort of common for BOTH Scat and Eagle cranks to need to be turned because their journals are not perfect (but Eagle cranks are usually better).

Vettrocious

This is where we've already exceeded my knowledge of the bearing end of things, so please bear with my dumb questions. It is my understanding that the block has large journals already, but I'd like to verify that. Can you tell me what to measure and what dimension to expect, in order to validate where I'm at now?

Thanks,

Mike

68hemi

Your cam choice will depend on if you are going to run headers or manifolds. The cam you speak of is similar to what I have and I have 2 1/2" manifolds. Bearings are the easy part and pretty much ANY good bearing like Clevite will be fine.

Vettrocious

I'll be using stock 2 1/2" fuelie manifolds.

I intend to stay with stock valve covers, so, I'm not sure where that leaves me relative to using a roller cam...

Mike

karkrafter

DZ, I have a question for you, personally line boring scares me...and it's expensive...years ago speed-o-motive [now closed] made a small journal stroker crank...why not just whittle down the journals on the bigger crank...I know the argument between large and small, don't need to go there, but I always hear line bore but never regrind the crank, again gotta be MUCH easier and cheaper...Guys raced small journal engines for years and years and....

68hemi

You have not said what look you are going for with this engine? Are you trying to give the appearence of a 327/350 h.p.?

You can always buy valve cover spacers and longer valve cover bolts for clearance. Roller cams are EXPENSIVE but will give you more power. I chose to go with a standard type hydraulic cam that is all done at 5800 rpms to insure I would not over rev and hurt the engine. I am using roller tipped steel rockers. I have not dynoed my car but believe I have 450-475 h.p. at the flywheel based on the old days type ratings. That is plenty for my 2850 lb. car that I street drive regularly. That is pretty good for the restrictions of the dual quad intake and exhaust manifolds I am running. I could easily be way over 500 h.p. with a good single carb, different intake, headers and compatible cam for the headers for WAY less money than I spent to build my look-a-like 283/270 dual quad engine. It is all in what you are looking to create. There are a lot of 500+ 383s out there today.

amtronic1

You can piece-part it, or just get one of the many 383 kits out there. Definitely aluminum heads, too.

.

DucatiDon

That's because of your air cleaner. Using the stock 65-66 air filter base will solve the hood clearance problem. I have the taller Z28 intake in my car and no hood clearance issues, with wing nut and all.

DucatiDon

If your aluminum heads have raised valve cover rails, like the AFR, the stock valve covers will clear the roller rocker trunions with no modifications. Otherwise you may have to use double thick gaskets.

Patrick03

Sounds like a fun project Mike! I'm still working on my 383 build, but here are some tips I'd offer up: I followed the engine build directions in . Easy to follow and explains things nicely. The next tip would be to buy bare heads and have your machine shop do the assembly. That way it is easily known what parts are used and your machinist will likely do a better job. I still recommend that shop I mentioned to you in another posting (14 Mile and Groesbeck area). Good luck with everything and keep us posted!

Patrick

Vettrocious

I'm looking to build a 383 with 425-450 HP at flywheel. Don't need more. Last year I began to alter a Rochester FI plenum for FAST port fuel injection; I'd like to put that on it and make it look close to a stock FI engine.

Don't really want to buy a 383 "kit" and just assemble it. This is intended to be just a fun learning experience, so I'd like to understand why I choose every component.

Mike

Vettrocious

Thanks, Patrick, I intend to have any machining necessary done there. In that regard, maybe you can answer my above question, i.e. what do I measure to verify whether I have the "large" journals?

I've already watched a bunch of Utube videos on SBC engine building, so that's a start

DucatiDon

Do you have 2 bolt or 4 bolt mains? If 4 bolt its large journal.

You measure the crankshaft (if you have one) where it sits in the bearings, or the inside of the crankshaft caps.

Patrick03

I lifted this data from another site, so can't attest to its accuracy, but it looks right to me:

Early block mains (small journal) were 2.2983/2.2993 with main bearing housing id. 2.4906/2.4916

Late block mains (large journal) were 2.4479/2.4488 with main bearing housing id. 2.6406/2.6415.

In my case, my block was a small journal and I had it line bored to large journal as the stroker cranks all appeared to be large journal and it made more sense to machine the block than to machine the crank.

Patrick