consultation - used 383 or motorhome 440 ?

[70bigblockdodge]

If I got taller pistons for it (then honed/ringed it) it would need balancing, correct

They should be close enough. I'm sure everyone will jump in and scream away about messing up the factory balance (which is crappy, BTW, just weigh the next set of eight piston and rod combo you pull out and see how far off the weights are).
Your also asking the guy who sanded down a .030 piston to make it STD bore and after 4k miles it's still happily going up and down in there.
So weather or not to listen to me is up for debate.

 

[413]

Your also asking the guy who sanded down a .030 piston to make it STD bore and after 4k miles it's still happily going up and down in there.
So weather or not to listen to me is up for debate.

After admitting that it’s best to not take any advice from that source.

 

[fury fan]

Well... I'm sure there are a whole lot more details about how, and why, he resized one piston, so I'll not discount him.
I'm actually now kinda curious.

 

[cbarge]

Furyfan...I removed the original 516's. After 256,000 miles they were rebuilt few times before and were worn out with burnt valves again.
The car ran ok before burning a valve but runs much better today than ever before.
Reason? The 452's were massaged. I mated them up with 68-70 "301" cast iron intake with crossover blocked. 625 edelbrock carb electric choke. Tti 2.5 exhaust factry lo-po logs. Pertronix ignition in recurved Chrysler dizzy .
Still running stock cam btw.
Very reliable combo that works very well and looks stock.
Cheers

 

[furious70]

Imo stockish 516's are junk after experiencing them myself. I changed 452's for 516's with 1.74"s replacing the 1.6's and a throat cut and they are crap.
I do have a heavy ported set of 516's that Opel here in streamwood said looked good but I'm not sure I'll ever use them.
Do 70's truck engines have the boss you need from high mount ps pumps?

 

[Gerald Morris]

In my opinion build the 383.
It is a running engine (albeit not well but it runs) and the rebuild cost can be lower compared to modifying the smogger 440.
Put the 452 heads on the 383.
Makes the engine breathe better than the small valve 516's. 452 aleady have hardened seats so that alone is a cost savings at the machine shop.You will actually gain more torque despite dropping compression by half a point. That can be an advantage with todays quality corn fed gas pumps.
I am running 452's on the 383 4bbl 66 300 seedan. Gobs of torque . Runs 75 mph all day never overheats and drove to Carlisle 2016 at 18 MPG.
Hope this helps.

Thank you! This is the sort of advice/data I seek from these discussions. The fact that 452 heads DO come with hardened valve seats has crossed my mind.

 

[twostick]

I wouldn't trade 57 cubes if the 383 was fresh from the machine shop.

If this is a completely bucks down project, I would rering and bearing the 440, clean up the heads with a basic valve job and if a new camshaft isn't in the budget, install a new multi key roller timing set and degree in the old one 4 degrees advanced. Dual exhaust at least 2.5" with a stock intake a fresh Thermoquad and recurve the distributor.

Put a set of 3.23's behind it and a factory hi stall converter if you have one around and prepare to be astonished at how a pos smog engine can haul the mail.

Kevin

 

[fury fan]

Do 70's truck engines have the boss you need from high mount ps pumps?

Reportedly like all bigblocks blocks from mid-70s and up have the bosses, this 440 is a 74 and has them, so not sure where it started.
All 65-newer 383s that I've seen have them (haven't looked at older 383s).
All 65 413s should have them, too.

I wouldn't trade 57 cubes if the 383 was fresh from the machine shop.

If this is a completely bucks down project, I would rering and bearing the 440, clean up the heads with a basic valve job and if a new camshaft isn't in the budget, install a new multi key roller timing set and degree in the old one 4 degrees advanced. Dual exhaust at least 2.5" with a stock intake a fresh Thermoquad and recurve the distributor.

Put a set of 3.23's behind it and a factory hi stall converter if you have one around and prepare to be astonished at how a pos smog engine can haul the mail.

Kevin

That's an interesting concept for sure, but those are some parts I don't have right now, and is more work than I can expend right now -- too many more things to do around the house.

As for the 57 cubes, I'd say this 440 is on the low end of hp/cu in capability, making the 383 more attractive to me under the circumstances I'm in right now. It's also the simplest one to get put together. If I stumbled across a taller set of pistons for the 440, I would feel differently, but I'm sure that would then snowball into a full rebuild, which I don't have time to focus on.

 

[twostick]

Reportedly like all bigblocks blocks from mid-70s and up have the bosses, this 440 is a 74 and has them, so not sure where it started.
All 65-newer 383s that I've seen have them (haven't looked at older 383s).
All 65 413s should have them, too.


That's an interesting concept for sure, but those are some parts I don't have right now, and is more work than I can expend right now -- too many more things to do around the house.

As for the 57 cubes, I'd say this 440 is on the low end of hp/cu in capability, making the 383 more attractive to me under the circumstances I'm in right now. It's also the simplest one to get put together. If I stumbled across a taller set of pistons for the 440, I would feel differently, but I'm sure that would then snowball into a full rebuild, which I don't have time to focus on.

I understand all that but if you are hesitating because of the low compression ratio of the 440, rest assured the 57 cubes will more than make up for it in comparison to the higher compression 383. If you were to have a cam ground to maximize the potential of a 7.8:1 440 you would see even more. Displacement = torque, always.

Also don't take the advertised compression ratio as gospel. In reality those numbers are typically a full point more than actual. That 383 if it shows say 9.5:1 on the spec sheet will be lucky to actually measure in a 8.5:1.

Kevin

 

[furious70]

Come buy one of my low cr 440's that run for cheaper than any of these options

 

[fury fan]

Not a bad idea Furious, but that's $$ and a 3+ hour drive each way.
Trying to use what I have on-hand, and whichever engine I go with will likely sit for several years until I need it.
This is also an exercise to keep both of them de-rusty and de-seized, too.

I understand all that but if you are hesitating because of the low compression ratio of the 440, rest assured the 57 cubes will more than make up for it in comparison to the higher compression 383. If you were to have a cam ground to maximize the potential of a 7.8:1 440 you would see even more. Displacement = torque, always.

Also don't take the advertised compression ratio as gospel. In reality those numbers are typically a full point more than actual. That 383 if it shows say 9.5:1 on the spec sheet will be lucky to actually measure in a 8.5:1.

Kevin

Agreed, but I'm not really focusing to pursue RB torque. I'm looking for whichever will run better/'cleaner', with the parts I have on-hand, and minimal cash outlay. I haven't seen the bores/down-hole of the 383, so can't really compare them from a performance standpoint, so my mind is not yet made up in that regard. But from a health standpoint, I have much more info on the 383, but it still has unknowns also. I am going to pursue the 383 for now - mainly because it is hooked up to run and needs less effort to get to the next step of evaluation.

If the 383 only needs a head to solve the dead cylinders,, then based on some comments above, I'll remeasure my cam measurements and try the 452 heads and see how that goes. If it then seems suitable to save as a backup, the 516 heads on the 440 may happen later on. (If 516s were good enough for a 66 TNT, they'll be good enough for me.)

 

[Gerald Morris]

Come buy one of my low cr 440's that run for cheaper than any of these options

What would you want for one? I'm always looking for good deals on a power plant! Mind you, my current 383 does very nicely, but I like planning ahead.....

 

[fury fan]

Got back onto this again, and pulled a head off. Definitely 2 burned valves.
Cylinders don't look fresh, but no ridge at all. And the other 6 cylinders on this engine were 140-155 psi, so this seems like a good one to re-gasket.
I haven't had any coolant in this one yet, so I'm still a little apprehensive of freeze cracks. I did seal off all the hoses, etc, and pressurize to 30psi with air, and it bled down very slowly. But air molecules are smaller than water, so maybe wasn't a conclusive test.

So if this gasket is correct, and if I interpret it correctly, the blue cooling passages cool the cylinders and get blocked at the gasket, the small slots at the upper passages allow bubbles to purge, while the 2 big passages at each end of the head (green arrow) are the sole inlet/outlet thru the head.

thoughts?

 

[furious70]

What would you want for one? I'm always looking for good deals on a power plant! Mind you, my current 383 does very nicely, but I like planning ahead.....

$500-1000 depending on condition. Msg me if interested