340 or 360 for hp

[Rob C]

Thanks Cranky. Good advice for next time.

Rumble, got any experience with the 318 stroked at stock bore?

Sorry, none at all personnaly. I have a 318 on a stand awaiting funds. (LOL!)

 

[moparleo]

Hi I'm new to the site but it looks like there are a lot of opinions out there, and too much rocket science for a question that was pretty simple. So here is my 2 cents from experience. The 340 has been discontinued for about 40 years now. The 340, like the chevy 302 was designed to make horsepower at high rpm at the expense of low end torque. I don't know about you but I got tired of hearing that thing scream. Also , if the engine shows any history of being apart , you don't know if it was rebuilt because of high miles, failure from overheating, which also is the number one cause of vehicle breakdown, And the quality of the machine work done by someone else. Since it seems that you already bought the engine, I guess you will find out from the machine shop what you got. The 340 has a thin cylinder wall and does not lend it self to being beat on after a rebuild for very long. If this is for the street. With occasional high rpm use get a Mopar crate motor. A lot lower final cost,all new parts,factory warranty, What is better than that? And you won't have to worry about the quality of the finished product. Just my 2 cents.

 

[btceng]

Moparleo, thanks. I'll take it $.02 at a time and save up til I no longer have to beg from you guys. I'm kicking myself now for buying this thing. Welcome to the site.:eusa_wall:

 

[btceng]

Update! I got the shortblock 340 to the machine shop for a clean and inspection. More bad news. 6 of the 8 pistons had cracks in them and it needs a .060 bore to clean it up. My guy says $2200 for a rebuild of the bottom end and that's just polishing the cast crank which is already .010/.010. I think I'll let him bore it and polish the crank and align bore it. Then take my time and build it back myself. Not ready for that kind of investment with paint, body, and interior left to do. To think, this was going to be an easy project. I don't know if I can afford to have this much fun.

 

[moparleo]

Please take some advice. You will be sorry if try to save a 340 block that needs to go .060 over and still needs at least $2200. That is crazy money especially if this guy says that is just polishing the crank,to rebuild the bottom end. Save your money now and sell it for whatever you can get. It will not be worth the can of worms you are going to open. I learned the hard way that it is cheaper and smarter to save up the money and do it right the first time than trying to get by on a compromise. You know ,if you have been reading these posts that really anything over .040 on a 340 block is about max. And that is if you sonic check the block first to make sure you don't have excessive core shift of the cylinder walls. Cut bait and wait. JMO Here to help, really.

 

[shadango]

+1 If this were the original motor for the car, I could see going this route.

But at this point? Cut bait and buy a crate.

Or, so you can drive the car, find a cheap used, running motor to throw in there for now...318, 360, whatever.....and save up the pennies for what you want so you can get it at a later date but still drive the car and enjoy it.

 

[btceng]

+1 If this were the original motor for the car, I could see going this route.

But at this point? Cut bait and buy a crate.

Or, so you can drive the car, find a cheap used, running motor to throw in there for now...318, 360, whatever.....and save up the pennies for what you want so you can get it at a later date but still drive the car and enjoy it.

I have a great 318 out of the car that runs good and looks like new on the inside. I was looking for a little more and the 340 mated to the 727 seemed like a worthwhile gamble until I pulled it apart. Thanks for the advice and same to Moparleo.

 

[btceng]

On second thought, I could go all out on the 318 with a forged stroker kit and still come in under that $2200 price tag. That price did include all assembly, parts, and machining. This machinist is highly reputable and is "the" go to guy around here. I'm in it with him currently for $140 for the clean and inspection.

 

[moparleo]

Mmmh. If you have a good driver motor, I would use it as is. Save your pennies and get something later to really be proud of. Decide what you really want your engine to do before you buy any parts. Remember ,you will get optimum performance from your engine if all the parts complement each other. That is the purpose of manufacturers selling parts in kits that have been developed to deliver a certain performance level. Much better than to find out after the build that it doesn't perform as good as you hoped and need to spend more money to do it. Unless you plan on superchargeing, turbo charging or nitrous the stock bottom end will be plenty strong enough. Put your money into the cylinder heads. This is where you get the most return for your money.

 

[Chryco Psycho]

Why not get a 88-92 360 from a wrecker for $200 or os & start with that , the 360 makes a lot more torque or you could stroke that for the cost of buying parts to rebuild anyway

 

[71 challenger]

340 6 pack is tough to beat and afford and tune and find

 

[btceng]

Why not get a 88-92 360 from a wrecker for $200 or os & start with that , the 360 makes a lot more torque or you could stroke that for the cost of buying parts to rebuild anyway

Probably the best option.

 

[btceng]

Can anyone suggest a source for a crate short block or complete motor? I don't really need the top end.

 

[Chryco Psycho]

Well I cannot recommend Mopar .Muscle Motors maybe in Michigan

 

[moparleo]

Hughes Engines is big on LA engines.

 

[Cranky]

Hi I'm new to the site but it looks like there are a lot of opinions out there, and too much rocket science for a question that was pretty simple. So here is my 2 cents from experience. The 340 has been discontinued for about 40 years now. The 340, like the chevy 302 was designed to make horsepower at high rpm at the expense of low end torque. I don't know about you but I got tired of hearing that thing scream. Also , if the engine shows any history of being apart , you don't know if it was rebuilt because of high miles, failure from overheating, which also is the number one cause of vehicle breakdown, And the quality of the machine work done by someone else. Since it seems that you already bought the engine, I guess you will find out from the machine shop what you got. The 340 has a thin cylinder wall and does not lend it self to being beat on after a rebuild for very long. If this is for the street. With occasional high rpm use get a Mopar crate motor. A lot lower final cost,all new parts,factory warranty, What is better than that? And you won't have to worry about the quality of the finished product. Just my 2 cents.

The 340 was nothing like the 302. The 302 even came with a solid lifter cam and produced 290 hp. Yeah, the 302 was very high strung for the day. I've had a few 340 powered cars and didn't have any problem with low end performance even with 3.23 gears. Now if you were talking about the 6 pack 340 being somewhat high strung then yeah, I'll agree with that but even it had decent street manners....

Update! I got the shortblock 340 to the machine shop for a clean and inspection. More bad news. 6 of the 8 pistons had cracks in them and it needs a .060 bore to clean it up. My guy says $2200 for a rebuild of the bottom end and that's just polishing the cast crank which is already .010/.010. I think I'll let him bore it and polish the crank and align bore it. Then take my time and build it back myself. Not ready for that kind of investment with paint, body, and interior left to do. To think, this was going to be an easy project. I don't know if I can afford to have this much fun.

I'm with the others about 2200.00 in just the bottom end. What's he doing for that kind of money?

 

[btceng]

That includes the machining, boring to .060, new bearings, polishing the crank, new pistons, oil pump, windage tray, and balanced assembly. It figures to about $1100 for the machine work and $1100 for parts and assembly. That also includes the $140 that I owe for the cleaning and inspection. Bargain or no?

 

[ramenth]

That includes the machining, boring to .060, new bearings, polishing the crank, new pistons, oil pump, windage tray, and balanced assembly. It figures to about $1100 for the machine work and $1100 for parts and assembly. That also includes the $140 that I owe for the cleaning and inspection. Bargain or no?

Bargain? I don't know. It might be the going price in your area. I've had a lot more machine work done for about the same price. But, again, that's the difference in areas of the country. What my being the going rate in one area is expensive, or a bargain, in another.

 

[moper]

I think it's fair money for the work. You still need heads too. I've always been one ot try and get the body done first. Reason being it always takes linger and costs more than you think, and engine parts don't store well unless you have the insde temp controlled space.

 

[Cranky]

I just had a 340 T/A block align bored and honed and decked, cleaned, new cam bearings and brass freeze plugs and the rods magnafluxed resized and rebushed for 445.00 if that helps gives you an idea. Stock type pistons will be going back in but I don't remember what they cost. I'll be doing the assembly. A balance job is forth coming and that will be about 200. I don't recall the cost of the pistons but I think they were about 250. Gaskets are in along with bearing and rings, oil pump etc. So far everything is still under 1500 but the heads haven't been worked yet and we still need the carbs.