340 Rebuild "Musts"

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moper said:
I'm with RAMM on most of his points although I use a 5/16 drill bit for the main feeds because that's what I could get quickly at the time years ago.
I own a good, certified sonic tester. I get paid to test others blocks, including some shops'. I would not sonic test a stad bore block going +.030 unless it was for a longer-than-stock stroke. It is not a necessity. There are times I do consider it but a 400hp 340 ain't one.
I do always line hone. That's so the CNC can have a confirmed straight centerline to index off of.
I always square deck - height TBD depending on the pistons and combinations but I can set deck height where I want that way, and know it's right for all of bores.
A good performance valve job on the factory heads will supprot the power level. I'd run a solid lifter because it will make the number and add some lower end grunt over a hydraulic. But that adds valvetrain cost due to the need for adjustability. If not, a hydraulic with the stamped steelies can certaintly make that power level. I've made 480 going off mph and weight using them and a hydraulic shelf grind cam.

I have no idea why redirecting oil or full grooved mains or "tight crush" would be needed here.
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I never do one without full groove mains. They cost the same. Same reason for using more crush. Just like squaring the deck, you are already there.
 
skrews said:
I hope your goal is more than 400HP
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Nope. It's a street car any sissy could drive every day.

I'm still trying to figure out how you get 10.5:1 compression unless the piston is out of the hole. It's not possible. For Christs sake it's even in the Chrysler book. Unless you cut the piss out of the head.

And then we can discuss lowering the crevice volume.......
 
j par said:
Can a crank be reground off set to add stroke ?
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Yes. You get half of the difference.

So, if you have a 2.125 pin and take it to 2.00 you get about .060 depending how well the crank is indexed to start with.

Hey, what's up with that fiberglass bumper? Did you get ahold of your buddy and see what he wants for it? My 73 Demon needs that thing.

Let me know.
 
Dart sport !
please take that conversation to our own thread this posters Thread is mucked up too much!
 
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No problem it seems to be pretty obvious when your meds are messed up these days LOL
 
Lustle said:
Here's a simple list:

Sonic checking - Must if you are boring it out. An excellent way to waste thousands of dollars is to bore it out without checking and end up with a cracked block. Yes a .020 is almost never going to hurt it. But better safe than sorry.
Align boring - Always a must. You want things to "line up" don't you? Align boring is a basic of "blueprinting" a block. It will line up center lines to the bore. Makes sure everything runs well and within spec.
Decking - This is up there with Align bore. Decking along with align bore will make the engine "square". Meaning everything will be equal to everything else. Bores will be lined up to cam/crank center lines. The deck line will be square to the crank line, which is also very important. Or else you end up with an engine where a piston in cylinder 7 might be .004 out of the hole and on cylinder 1 it's .004 in the hole. Not good.
Bushings - Just replace them. They are cheap. And fresh ones offer good insurance against anything else that might go wrong. A lot better to wear a new bushing/bearing then it is to throw a rod.
Aftermarket rod bolts - Once again, just cheap insurance. Rod bolts stretch. I wouldn't re-use them.

Any of these should really be done on ANY rebuild. Yes it costs money. But how often do you want to rebuild the thing? And as I keep saying with engine building. The devil is in the details. A properly balanced and bluprinted engine, with a strong hone, good decking and excellent rings. Can be worth an EASY 50hp over a thrown together engine without attention to the detail.

Only thing I don't think is ABSOLUTELY needed. Is new rods. If it is a 71. It should have forged rods. As long as they spec out. Give them a shot peen and polish. Then throw some ARP studs in them and back in the engine they go.

Now if you want an idea of 400 horse. My setup was rated (probably under rated) at 380 horse with the 340 manifolds. Now I have headers and a much better exhaust on it. I figure it's about 420 horse.

340 block, with all the work I mentioned above. As well as checking oil galleys, clearences, etc etc. Basically a full balance/blue printing. These details make a difference.
Stock forged crank/rods
.040 overbore
Keith Black 243 hypereutectic pistons
J heads, 1.88 intake valve opened to 2.02. Stock 1.60 exhaust valve. Excellent valve job (3 angle with back cut if I remember, Ill have to check the build notes). And while they did the valve job they also did light cleanup work on the turn, port and bowl.
Comp XE274H with comps recommended kit (lifters, springs, locks, timing gears/chain, etc) comp pushrods
RPM Air gap
HV oil pump
Stock 340 A body pan
Rebuilt/recurved stock style electronic distributor
Rev-n-ator ignition box

Right now. I have a garbage 12 year old 670 street avenger on there. It's some cheap chinese crap. The metal is flaking bad and can't be fixed. I also think I have some distributor problems. I am going to switch over to the distributor recommended by rev-n-ator. I am also changing over to FItech 600hp power adder setup. First I'll just run the fuel side of it. Let it learn, get a tune, see how it does. Eventually I will use it to run timing and nitrous as well. I've heard A LOT of great things about the FItech setup. Mike at MRL has used them on his last few builds and says the thing runs excellent and is worth a few hp over the usual carbed setups.

But as is right now. With 245's out back. A 4.10 gear set. A 2400 B&M off the shelf torque convertor (which I'm replacing with a custom built PTC unit as well). The thing will ROAST the tires at will. Anything over 1/4 throttle in 1st/2nd will light them up on completely dry pavement. If I mat it in drive. It will burn the tires all the way into 3rd easy. I can be cruising at 50k in second and if I push that throttle it'll light them up in the middle of the road. So it's definitely making good steam.
Click to expand...

Great Article Would love to Know How you got on with the Fitech Do you need to Run an EFI camshaft.
 
yellow rose said:
Nope. It's a street car any sissy could drive every day.

I'm still trying to figure out how you get 10.5:1 compression unless the piston is out of the hole. It's not possible. For Christs sake it's even in the Chrysler book. Unless you cut the piss out of the head.

And then we can discuss lowering the crevice volume.......
Click to expand...


If running iron heads he won't want 10.5:1 compression on the street. That is why I recommended 9ish:1 for pump gas. This allows him to have a safe combo that won't detonate with a bad tune. Most novice guys are just learning to tune with timing and carbs. That's why I gave him a good starting point for initial timing,full advance and when to bring it in. I just went thru all this with help from members here. I was only trying to help him get a fun combo without overwhelming him with crazy combos. I do see the validity of your thought process but this guy is starting out. Not building a pro stock engine. I have a buddy running a 340 car with a blower making 9lbs of boost on stock iron adjustable rockers. Makes plenty of power and rpm. Still running strong.
 
j par said:
I agreed with everything up to - I have a buddy...
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A guy you know...a guy who acknowledges he may possible know who your are...the guy with the bumper. Does he want to sell it, trade for it or donate it to the yellow rose memorial foundation for the promotion and protection on 1973 Dodge Demon automobiles?
 
younggun2.0 said:
If running iron heads he won't want 10.5:1 compression on the street. That is why I recommended 9ish:1 for pump gas. This allows him to have a safe combo that won't detonate with a bad tune. Most novice guys are just learning to tune with timing and carbs. That's why I gave him a good starting point for initial timing,full advance and when to bring it in. I just went thru all this with help from members here. I was only trying to help him get a fun combo without overwhelming him with crazy combos. I do see the validity of your thought process but this guy is starting out. Not building a pro stock engine. I have a buddy running a 340 car with a blower making 9lbs of boost on stock iron adjustable rockers. Makes plenty of power and rpm. Still running strong.
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Really? I have been running measured 10.5:1 and higher on iron heads and pump gas since 1982. My personal car is 11.08:1 (actual measured) on iron heads, on pump gas. If I change the head gaskets it will be 11.25:1 and still run on pump gas.

The compression ratio/iron head/street car/pump gas myth deal should have been long dead but evidently, it's still alive and well.

It's like we are stuck in 1986 again.

DOWN WITH THE MULLET.
 
Look ya goof I bumped our thread up - small block part of the Forum you remember the hillbilly stroker vs cracked Machinist please leave the op's threat alone for the last time
yellow rose said:
A guy you know...a guy who acknowledges he may possible know who your are...the guy with the bumper. Does he want to sell it, trade for it or donate it to the yellow rose memorial foundation for the promotion and protection on 1973 Dodge Demon automobiles?
Click to expand...
 
younggun2.0 said:
If running iron heads he won't want 10.5:1 compression on the street. That is why I recommended 9ish:1 for pump gas.
Click to expand...

yellow rose said:
Really? I have been running measured 10.5:1 and higher on iron heads and pump gas since 1982. My personal car is 11.08:1 (actual measured) on iron heads, on pump gas. If I change the head gaskets it will be 11.25:1 and still run on pump gas.

The compression ratio/iron head/street car/pump gas myth deal should have been long dead but evidently, it's still alive and well.

It's like we are stuck in 1986 again.

DOWN WITH THE MULLET.
Click to expand...

I hate general statements like "oh if you got iron heads you can't run more than 10:1" or something. There is so much more that goes into it. You have to know your cam specs, IVC mainly. You have to know your chamber type. Head material. Spark plug. Distributor/coil strength. How good is your tune. And the one thing everyone seems to forget, elevation. There's so much that goes into it. Telling someone "oh don't run more than 10:1" when they got a cam in there with say 300+ advertised duration and an IVC in the mid 70's is a great way to make a dog engine.

At my elevation, 10:1 compression, even with a mild cam with 60* IVC and mild overlap of 54 degrees. Give's me a whopping 145-150 psi cranking pressure. When really max "safe" cranking pressure on an iron head motor is closer to 185 psi on 91 pump. And yes. 35-40 psi is a ton of power. So there is soooo much more to it than "you can't run more than". In fact I'm looking at going solid roller. And if my cam ends up where I think it will, I'll probably end up running close to 11.5:1(static) on an iron head motor. And be very safe on 91. I could even run more, we got 94 pump gas around here.
 
moper said:
I'm with RAMM on most of his points although I use a 5/16 drill bit for the main feeds because that's what I could get quickly at the time years ago.
I own a good, certified sonic tester. I get paid to test others blocks, including some shops'. I would not sonic test a stad bore block going +.030 unless it was for a longer-than-stock stroke. It is not a necessity. There are times I do consider it but a 400hp 340 ain't one.
I do always line hone. That's so the CNC can have a confirmed straight centerline to index off of.
I always square deck - height TBD depending on the pistons and combinations but I can set deck height where I want that way, and know it's right for all of bores.
A good performance valve job on the factory heads will supprot the power level. I'd run a solid lifter because it will make the number and add some lower end grunt over a hydraulic. But that adds valvetrain cost due to the need for adjustability. If not, a hydraulic with the stamped steelies can certaintly make that power level. I've made 480 going off mph and weight using them and a hydraulic shelf grind cam.

I have no idea why redirecting oil or full grooved mains or "tight crush" would be needed here.
Click to expand...
Simple common sense, in layman's terms....
 
The cost of bushing the lifter bores is so small (I do it for $125.00 plus the tube) that it's STUPID not to do it. The oil timing on chryslers is jacked up, so why not help it out?

You are not bushing the lifter bores....you are running a tube thru the oil gallery....big difference in price.....LOL

And I guess I am stupid...as none out our engine are....and they are solid lifters....
 
yellow rose said:
Really? I have been running measured 10.5:1 and higher on iron heads and pump gas since 1982. My personal car is 11.08:1 (actual measured) on iron heads, on pump gas. If I change the head gaskets it will be 11.25:1 and still run on pump gas.

The compression ratio/iron head/street car/pump gas myth deal should have been long dead but evidently, it's still alive and well.

It's like we are stuck in 1986 again.
Click to expand...

I know that you are running 10.5:1 or higher on iron heads da dada on the street, simply because YOU know your shxxt (or most of your shxxt) like no other, and you are very confident in it. There is absolutely positively nothing wrong with that. That is the way engines can be built when you know what you're doing and when you have the means and knowledge to check stuff and troubleshoot when something's off.

BUT, the OP is asking advice as a novice, and he probably does know about 5% from what you know... so it seems much smarter to give a bit more conservative advice. That doesn't exclude basic machining like boring, decking, double checking evey measurement and such... ok the rest has been said by others.

Sometimes it's good to stay somewhere between 1968 and 2017.
 
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This one gave me a headache lol..... There is some interesting information here if the OP can absorb some of it.....

There is no doubt the OP should call someone like Bullet for the cam. Tell them all the specs you can and your intended use of the motor. You are buying a Camshaft no matter what and this will yield you some gains. Off the shelf is OK too but even anyone should take advantage of R&D knowledge from the Cam companies....

Good luck OP,
JW
 
Just my take;
- For 400 HP on the street, and a .020" or .030" overbore, I would not sonic test unless I had reasons to doubt the block. BTW, you can get .020" over pistons from KB for this, and if you go .020" over on the 1st bore instead of .030", you can get an extra boring cycle out of the block.
- Align bore is an option in my book at this level. I've done a dozen or more 1.2 HP per cubic inch engines and a few 1.75 HP per ci turbo engines and all have done fine on bearing wear and everything with no align boring.
- I assumed when I last asked for 'decked' that they would 'square deck' since they knew we doing a good build. My assumption was wrong! Ask for 'square deck'; that makes the deck perfectly perpendicular to the bores. It will still run fine is not perfectly square, but measurements of piston-to-deck height get harder to make consistent.
- Some form of crack detection exam of the block is an insurance policy that I like to pay for.

BTW, your path to 400 HP will be easiest if you get flow into the heads. The cam can be made bigger to compensate, but then you will give up low end torque and make the motor 'peaky'. If smooth street driveability is your goal, then start with head flow, so you can keep the cam durations down for better low end torque.

Ditto for putting the SCR up in the 9.5-10.0 range: torque band will be wider, and low end RPM driveability better.
 
70aarcuda said:
The cost of bushing the lifter bores is so small (I do it for $125.00 plus the tube) that it's STUPID not to do it. The oil timing on chryslers is jacked up, so why not help it out?

You are not bushing the lifter bores....you are running a tube thru the oil gallery....big difference in price.....LOL

And I guess I am stupid...as none out our engine are....and they are solid lifters....
Click to expand...


Right, I originally said bush the gallery but you KNEW what we are discussing.

I guess if you don't do it there must not be a need. Or you are a cheap skate. Or you can't simply ream a bore and drive in a tube.
 
younggun2.0 said:
If running iron heads he won't want 10.5:1 compression on the street. That is why I recommended 9ish:1 for pump gas. This allows him to have a safe combo that won't detonate with a bad tune. Most novice guys are just learning to tune with timing and carbs. That's why I gave him a good starting point for initial timing,full advance and when to bring it in. I just went thru all this with help from members here. I was only trying to help him get a fun combo without overwhelming him with crazy combos. I do see the validity of your thought process but this guy is starting out. Not building a pro stock engine. I have a buddy running a 340 car with a blower making 9lbs of boost on stock iron adjustable rockers. Makes plenty of power and rpm. Still running strong.
Click to expand...
I would agree to an extent here, the OP is getting His feet wet, and can use a little leeway. Also, it's easy after years & years of building/tuning/running to forget what it's like to not
know all the things You know now. I know YR means well, & 10.6:1 is not a problem w/an iron head at all IF You obtain a satisfactory squish to speed up the burn, but the advanced
efforts He is sharing are not necessary to accomplish the goal. I understand the more You build, One can develop an "all or nothing" MO, but unless the OP doesn't mind dropping
extra coin and may step up to a combo that would make all those mods mandatory.......it can wait if things check out as is......................
 
SLOPAR72 said:
This one gave me a headache lol..... There is some interesting information here if the OP can absorb some of it.....

There is no doubt the OP should call someone like Bullet for the cam. Tell them all the specs you can and your intended use of the motor. You are buying a Camshaft no matter what and this will yield you some gains. Off the shelf is OK too but even anyone should take advantage of R&D knowledge from the Cam companies....

Good luck OP,
JW
Click to expand...


Can't do a custom cam. He too new. He needs to call the rocket surgeons at summit or go to a forum and let them pick a cam.

Har-Dee-harr-harr.
 
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