440 TNT rebuild

[Jakub Varga]

Hello everyone. I have my stock, 1965 made 440 with 516 heads in machinist shop for rebuild. It needs 0.030 over pistons and I would also like some "lopey" cam in it. My '66 Chrysler 300 is a cruiser driven on 91 US octane fuel (95 is available). Can you please recommend suitable pistons (brand, valve reliefs or not etc.) and solid lifters camshaft? I'm concerned about raising the compression too much and valve to piston contact by milling the heads and block. Other helpful tips are much appreciated. Thank you very much.

 

[CBODY67]

Are you talking about the old US "Research" octane or 91 US "Pump" octane fuel? There IS a difference. Your engine was designed to run on 97 Research Octane fuels, as most "Premium" fuels for 10.0CR motors was in the 97-100 Research Octane range, when new.

The old US Research Octane rating of "91" would have been "sub-regular" and not suitable for anything over about 8.5CR, by comparison. "93" US Pump Octane fuel would basically equate to the old 97 Research Octane fuel.

These things DO relate to pistons. Would be a heck of a deal to build an engine and you can't find fuel to make it run like it should!

NO real advantage to using a solid lifter cam in a "cruiser" unless you like the sound and/or have the time to "run the valves" every so often. Aim for a 268/284/.475" lift cam, like the 440HP hydraulic or the 284/284/,475" cam of the '68 426 Street HEMI. All hydraulic cams so you can enjoy more time driving with less time wrenching. These cams will work best with a static CR of 10.0:1 .

One real advantage of a solid lifter cam is being able to run the intake valve clearance a bit wider than normal to effectively shorten the duration and bleed-off a bit of low end torque for easier launches . . . BUT I suspect you might also desire to send up some tire "smoke signals".

CBODY67

 

[Jakub Varga]

I was talking about 91 US pump octane fuel on which engine was either low on power or pinging when playing with timing. I then switched to 93 US pump octane fuel but did not have time to try the difference because freeze plug started leaking so I pulled the engine out for work during winter.

That is the reason why I'm not sure which pistons to choose. Will this 93 be enough not to ping with 0.030 over flat top pistons and hotter cam? Or is it safer to lower compression with pistons with reliefs or thicker head gasket? What about piston to valve contact when using suggested cam?

Thanks for the tips for the camshaft. Misspoke about solid lifters...meant flat tappet lifters. Sorry but I'm still learning all this things mostly here on the forum which is very helpful.

 

[67_300_Convertible]

The 440 in my '67 300 was recently rebuilt with flat-top pistons. It's bored .030 over and has 516 casting heads. Stock CR was around 10:1 and I am thinking it's about that after the rebuild. Timing at WOT is 33 degrees; cruise timing is 42 degrees at around 2500 rpm. On 93 octane pump gas with a 185 degree thermostat there are no issues with pinging unless I get on it hard on a hot day after sitting in traffic and letting the coolant temp rise. I run a Holley Sniper EFI and Hyperspark distributor, so I can fine tune A/F ratios and timing and keep a close eye on manifold air temperature, too.

I think this is the piston the machine shop used:

Sealed Power 350NP30 Sealed Power Cast Pistons | Summit Racing

Free Shipping - Sealed Power Cast Pistons with qualifying orders of $109. Shop Pistons at Summit Racing.

www.summitracing.com

 

[MONC440]

If you stay under .500 lift camshaft, you will not need any valve relief, use one of the cams cbody67 suggested and you will be fine. Just an FYI I have run the Mopar .509 hydraulic and the .528 mechanical cams with stock 69 HP pistons and 906 heads milled 0.050, WITH a modern felpro gasket that is .042 thick. If you are going with steel shim head gaskets (around .020 thick) make sure you stay under .500 lift and you will not have any issue.

Let me just ask is the machine shop doing the build or are you doing it? If they are doing it and you trust them, you tell them what compression ratio you want and have them choose your pistons. I say this because any machine work you have done will effect the piston you need, milling the block deck to straighten it out (highly recommend doing this), milling the heads to get them flat and the head gasket you use will all define the piston you need to reach the CR you want.

Milling the block shortens the deck height, so the piston is higher in the cylinder, increasing compression ratio. Milling the heads makes the combustion chamber smaller, increasing CR, thicker head gaskets lowers CR, pistons with shorter compression height will lower CR. If you are having the machine work done then take advantage of it and get it all correct so you know what the final CR is, not just a guess.

When I build engines this is my chosen steps.
1. Send block and heads to the machine shop, have the block decked if needed (90% of old blocks will need it, if it has never been done before) have the machine shop measure the new deck height and send me that measurement. Have the machine shop measure the bore and tell me how much over bore is needed. Have the heads milled if needed. Have the machine shop measure combustion chamber volume and send me that measurement.
2. I use the deck height and combustion chamber measurements to decide what pistons and head gaskets to order to get the CR I want. To do this you also need to know the stroke and connecting rod length.
3. Order the pistons and send them to the machine shop.
4. The machine shop bores the block to match the pistons you gave them. That way each piston can be matched to the bore.
5. Assemble the short block and check the the pistons are the correct height in the cylinder. If they are then use the head gaskets you originally decided on, if the piston is lower than spec you can use a thinner head gasket, if they are higher than spec you can use a thicker head gasket.

I see you are in Slovakia and I have no idea what kind of machine shops you have there so if you want help figuring this all out. Get the info listed above from the machine shop and we can help you figure it out.

 

[mr gtx]

I think this is the piston the machine shop used:

I hope not. if they didn't deck the block with those pistons you will be 75 thousand in the hole. they are heavy pistons with the thicker rings. you are at about 9.6 compression now if they are your pistons. the pinging you're getting because there is no quench.

 

[wyrmrider]

I hope not. if they didn't deck the block with those pistons you will be 75 thousand in the hole. they are heavy pistons with the thicker rings. you are at about 9.6 compression now if they are your pistons. the pinging you're getting because there is no quench.

 

[wyrmrider]

start with what monc440 said above cc your heads
choices
440 6 pack pistons at 0 deck with a "D" dish milled to get the cr you want maybe a 100 cc dish
KB quench dome pistons with the dome removed with dish you want for your fuel too bad no e-85
with a 9:1 motor Iwould run Howards 256 @.006 204@.050 .305 lift hyd cam
more compression larger cam depending on converter gears use etc do not go big in a heavy car with stock gears
do get a cam made for a mopar the stock magnum cam is a smog cam compromise way too long closing ramps
KEEP YOUR QUENCH LESS THAN..050 .030 better width of your head gasket

 

[mr gtx]

I used race-tech forged pistons. with closed chambered heads you will be about 9.5-9.6 compression with .039 head gaskets you will be about 10-12 thousands in the hole without decking the block. I decked mine 5 thousands so am 5 thousands in the hole with 9.6 compression. pistons are light weight and use the thin rings. they have a 14 thousand dish with a 2.070 compression height. the have the d-shaped dish for close chamber heads.

 

[rwilson]

Best piston to use is the Speed pro 2355

 

[Jakub Varga]

Thanks everyone for the replies, you are very helpful. I was just quoted cost of heads rebuild and it is higher than Stealth heads. So I'm thinking of going with them. My problem is, I need to order every part together because of shipping costs. First step should be to deck the block, then measure it and order correct pistons. Closed chamber head on Stealth heads is the same like on my 516? Is there a way to calculate quench to have correct gasket ordered without having these heads here? Thanks!

 

[mr gtx]

heads have nothing to do with quench. just need to know your block deck height.

 

[mr gtx]

Best piston to use is the Speed pro 2355

why are they the best piston ? they use the thicker rings and weigh as much as a stock piston. when you can get a piston that weighs 200 grams less per piston which saves you 3.5 lbs of your rotating mass. they also need about 1.5 thousand bore clearance which makes them rattle when cold. plus with a 2.061 compression height you would need to take the block more.

 

[rwilson]

the 2.06 is the closest stock replacement piston. Everything else(quench-final compression ratio) can be adjusted by the head gasket thickness

 

[mr gtx]

the 2.06 is the closest stock replacement piston. Everything else(quench-final compression ratio) can be adjusted by the head gasket.

why do you want a stock piston when you can get a lot better piston ?

 

[rwilson]

If there are Pistons out there with the same height, more power to you, I was just throwing option out there

 

[mr gtx]

If there are Pistons out there with the same height, more power to you, I was just throwing option out there

you can get any height you want or any dish or flat top. they are 300 dollars more than speed pro but on a total rebuild is not that much more plus you can save on decking the block if your block is not bad.

 

[fury fan]

heads have nothing to do with quench. just need to know your block deck height.

They don't in this case because the OP is using closed-chamber.
But heads absolutely matter when one is choosing between closed vs open-chambered. I stipulate that for future readers than might be considering a different engine combination.

 

[fury fan]

I hope not. if they didn't deck the block with those pistons you will be 75 thousand in the hole. they are heavy pistons with the thicker rings. you are at about 9.6 compression now if they are your pistons. the pinging you're getting because there is no quench.

FWIW, my calculator says a 440 with .030" overbore, std deck, and 1.99" CH, the piston will be .100" down.

@67_300_Convertible
Traditional thinking is that good quench is ~.040" and prevents detonation even though the CR is 'high'. (by creating high turbulence in the charge when piston hits TDC)
There are those that say that having higher CR, but with no effective quench, actually promotes detonation by higher heat and no turbulence. (this could be what your pistons are at?)
But it doesn't really matter for you at this point, sounds like you've got it tuned to run well.
Having smaller-port -516 heads, with higher port velocity on a 440, might be helping give the velocity/turbulence that helps prevent detonation.

 

[fury fan]

Thanks everyone for the replies, you are very helpful. I was just quoted cost of heads rebuild and it is higher than Stealth heads. So I'm thinking of going with them. My problem is, I need to order every part together because of shipping costs. First step should be to deck the block, then measure it and order correct pistons. Closed chamber head on Stealth heads is the same like on my 516? Is there a way to calculate quench to have correct gasket ordered without having these heads here? Thanks!

Aluminum heads permit more compression to compensate for the heat loss due to aluminum having higher thermal conductivity (IIRC they can be 1.0 higher CR?)
Alum heads also cannot use steel-shim gaskets, as the steel will eat into the aluminum. So you'll need to use 'soft' gaskets, and those are always thicker usually .040" or more.

When doing CR calculations, make sure to use the compressed thickness of a gasket. (but that's usually what is provided)
440Source should have published the cc's on the Stealth chambers. IIRC the -516 was published in the Mopar books as 70cc, but some reputable reports said real-world examples were usually 80cc.

There are a number of calculators on the internet, some have too much detail (they require specs you won't have, like volume of the annulus on top of the top ring), and some are too generic (if it doesn't require dish/dome cc, for example - run away!). Find some calculators, enter your numbers in each, and see how they agree.