Rebuilding 383 engine

[furious70]

Does the engine need rebuilt for any reason or is it just a more power deal? If the long block is in good shape a stroker is a lot of unnecessary cost per the articles.
Or, do like me and hang some snails or an iron lung on it!

 

[Gerald Morris]

I just watched a segment of Nick's Garage where he got 400 horsepower out of a 383.

Is the reason for the rebuild to get more power or because "it's time"?
....
. Do mention that you want it to last 100K miles instead, but run a bit better than stock. With a Cloyes roller timing chain, for longevity!

Just some thoughts,
CBODY67

MOST WISE advice. It occurs to me that one way to get plenty torque is to lengthen the moment arm over which force is applied, to wit: the stroke length. Were he to stroke that 383, couldn't he get about 426 in.^3 displacement, + pick up the 3/8 inch of length, increasing his torque by 10% ?

 

[CBODY67]

On the surface, just lengthening the stroke length should increase the torque, but with the same cyl heads/ports and cam, the resultant increase in CID would also make the cam effectrively "smaller" compared to the CID. Plus other side issues as "dwell time at TDC" of the piston and all that might mean to the intake and exhaust side of things. Plus special pistons to accomodate the additional stroke length (for the same piston deck height), even special connecting rods too, possibly. Using a 440 crank in a 383 also requires machining of the main journals to 383 sizs, as I recall, too . . . although such stroker kits might now be readily available from SCAT or similar. Resulting in a 452 "low deck" engine, typically. NOT to forget that the 440 has a "rod ratio" more in the torque side of things anyway, compared to the 383/400 whose ratios almost exactly match those of the Chevy 302 (bore to stroke, rod length to stroke), which is known for its "likes to rev" characteristics. FWIW

Enjoy!
CBODY67

 

[furious70]

Plenty of kits these days with the correct journals or using 2.2, no reason to waste a 440 crank.

But the OP needs to reply if his long block needs any servicing, of not, just follow the magazine article steps to the level of crazy you want, substituting a dual plane intake to that m1.

 

[Gerald Morris]

On the surface, just lengthening the stroke length should increase the torque, but with the same cyl heads/ports and cam, the resultant increase in CID would also make the cam effectrively "smaller" compared to the CID. Plus other side issues as "dwell time at TDC" of the piston and all that might mean to the intake and exhaust side of things. Plus special pistons to accomodate the additional stroke length (for the same piston deck height), even special connecting rods too, possibly. Using a 440 crank in a 383 also requires machining of the main journals to 383 sizs, as I recall, too . . . although such stroker kits might now be readily available from SCAT or similar. Resulting in a 452 "low deck" engine, typically. NOT to forget that the 440 has a "rod ratio" more in the torque side of things anyway, compared to the 383/400 whose ratios almost exactly match those of the Chevy 302 (bore to stroke, rod length to stroke), which is known for its "likes to rev" characteristics. FWIW

Enjoy!
CBODY67

Yes, stroking a 383 is NOT what I would do, given how Virtman designed that engine precisely FOR higher RPM, and did a SUPERB job of it at that. Yes, I looked at stroking a B block several years ago, and found that Silvolite, the parent company for lines like Keith Black, makes a good variety of pistons for stroked motors, or just for folk seeking minimal mass to optimize for power to the rotating assembly.

Nowadays, I would only advise machining a 440 crank if one had one already paid for, otherwise, it would be FAR better to buy one made for the purpose of a stroked engine. I think the crank journals are proportionally smaller, about 10% again. I corrected my earlier arithmetic too: one would get more like 421 cubes, not the mystical 426 from using a 440 or 413 crank in a 383.

Might make an interesting "Junkyard Special" for Uncle Tony though, but I reckon the best way to use a 383 for torque now is to obtain lower ratio gears in the rear end, say, 3:55 or even the 4:10 set rather than the 2:76 or 2:93 stuff the 2 barrel cars usually came with. One then can rev the motor up and apply power to the rubber with the lower ratio stuff. Watch the fuel gauge needle DIVE while the speedo needle pegs the right!

 

[furious70]

The relatively small bore of the 383 doesn't make it a great stroker candidate even though there are kits. For a boat tugger it'd be fine, but you shroud the valves and lose the advantage of bigger heads if you go that route. The 400 block is much nicer to work with when looking to do something serious.

 

[CBODY67]

Nicer as the 400 bore is the same as an overbore size for 440s.

 

[furious70]

And just a sweet bore to get some valves in

 

[Gerald Morris]

Let's not forget the crankshaft support webbing! Nice THICK webbing, and some ribbing on the sides too. Dumbell shaped ports for the coolant to flow through. The Ultimate B Block, which is why I jumped to get one a few years back. Just need to check it out, and get a new motor made of it.

 

[CBODY67]

Not to forget that the shape of the coolant orifices in the deck surface are restricted by the head gaskets, to ONE little hole at each location. The "hour glass" shaped coolant ports used to be the indication of a motorhome block 440, which allegedly needed the extra flow, as I recall. As with some other things on assy lines, always better to put visual indicators in than rely completely on paint daubs and such.

Enjoy!
CBODY67

 

[Gerald Morris]

Not to forget that the shape of the coolant orifices in the deck surface are restricted by the head gaskets, to ONE little hole at each location. The "hour glass" shaped coolant ports used to be the indication of a motorhome block 440, which allegedly needed the extra flow, as I recall. As with some other things on assy lines, always better to put visual indicators in than rely completely on paint daubs and such.

Enjoy!
CBODY67

VERY TRUE about standard head gaskets setting the size of that coolant orifice, BUT, IFF one wants more flow, its available! My 400 block, an RV motor, has the dumbell shaped holes, as expected. I looked at the bores when I got the thing, and it doesn't look bad at all, though it needs a more rigorous examination than my pulling the heads and just looking in. It got into a bog and sucked water, which is why I got it and the tranny for $250. Its a '77 block, but while not as beefy as a '71-72 casting, is still a respectable block to start with, IFF sound! It has the Maltese Cross on the boss, meaning undersized main supports I believe. Be that as it may, I think that barring hidden cracks lurking, it might make a very good replacement plant for a C body.

 

[furious70]

The figure 8 water passages are just a later casting, it's not motorhome or any other specific application.

 

[70bigblockdodge]

Always take a long arm engine over a short one. Unless your car weighs less than 3000# or has a 8 speed transmission.
Now I'm not saying to throw a stroker kit in every damn 318 boat anchor just because some magazine says you can't rebuild a stock bottom end for less than the $3000 it cost to get a stroker kit in my block. If I have a 440 and a 400 available, I'm putting the 440 in. Same goes for small blocks I'll take a 360 any day over a 318 or 340 any day. Too hard to get a short stroke engine to behave nicely with any decent cam in it. Which I suppose is the appeal of a 500" with cast iron heads, idles like a 318, runs like a 440 six-pack.

 

[Gerald Morris]

Always take a long arm engine over a short one.
....
Which I suppose is the appeal of a 500" with cast iron heads, idles like a 318, runs like a 440 six-pack.

YES! IFF I had ONLY bought that damned 413 in Phoenix just a few weeks before Mathilda's tragedy! I'm still looking for a decent RB, though for now that 383 is moving its freight well enough.

 

[70bigblockdodge]

The B engines are fine, but if I had a choice of the 2 the longer arm RB would be the winner.

 

[CBODY67]

The figure 8 water passages are just a later casting, it's not motorhome or any other specific application.

Somewhere, years ago, possibly in a Direct Connection Race Manual (back when it was ONE 1200page item), it mentioned the "Figure 8" passages and noted that was only on motorhome 440 blocks. Might have also been some mention of "greater flow", too. Yet when I mentioned this to my late machine shop operative, he kind of grinned. That's when the issue of orifice size/location in the head gasket/head deck surface came into reality. I also have a NOS 440 MHC short block (which I bought new from Chrysler during the "parts warehouse clearance days") that has the Figure 8 configuration. The application was for a 1972 application. Being as how it was factory 8.2CR, with the flat top pistons .125" in the hole, nobody wanted then, apparently.

Considering how those MHC440s seemed to be known for cooking spark plug wires and such, Chrysler put the Figure 8 holes on later model engines as a normal situation?

IF the cyl heads had matching Figure 8 holes in them (with matching head gaskets), THEN their "mass flow" orientation might be operative?

Happy Holidays!
CBODY67

 

[furious70]

I've had many regular truck blocks ranging in the 70's and they were figure 8.
Only the 66-70 stuff is a circle from what I've seen

 

[furious70]

I've never had an actual MH long block with the goofy heads and water pump, maybe they do take advantage of it, but all the blocks were cast with them that I've seen.

 

[CBODY67]

I did actually see a '72 440 MHC, a part, at my machine shop operative's shop. From the top side, the heads had the same intake manifold pattern as a norma B/RB engine, but with 4 seperate and distinct exhaust ports. The chamber looked like an LA combustion chamber. Seems like it had LA-style spark plugs, too? I traced the Holley 4160 number to a 1972 440MHC, for reference. Looked to me like it would have made a heck of a race/HP cyl head with a bit of finesse.

Enjoy!
CBODY67