Author Topic: 340 Rebuild advice  (Read 2013 times)

Offline William H Meister

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340 Rebuild advice
« on: December 24, 2008 - 12:08:45 AM »
I have a numbers matching 340 and a 4 speed. I have heard of people leaving the original engine on a dolly and putting a crate or donor engine in to protect the value of the car. I don't have deep pockets and wanted to get some advice on this. Also, if the block doesn't need bored is it wise to just leave it alone?
Any and all input is appreciated.

Bill




Offline bb71challenger

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Re: 340 Rebuild advice
« Reply #1 on: December 24, 2008 - 12:23:43 AM »
If I were you what I would do with shallow pockets is to get a boneyard 360 and have it rebuilt with as many quality parts as you can. Put the matching numbers engine away under a shelf in your garage. Put a nice warm 360 in your car and have a blast. No huge worries if you hurt it. 360's are not hard to find and give the best bang for the buck in the small block world. Good luck and let us know which way you go.
1971 Challenger (OO==== ====OO) getting close!
1970 Challenger (OO########OO) long ways off
*Brett*

Offline Chryco Psycho

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Re: 340 Rebuild advice
« Reply #2 on: December 24, 2008 - 03:55:13 PM »
 :iagree:
 I would NEVER bore a block if it didn`t need it but most do ust to get the clearances back & get the cylinders straight
 I remember reading about a SS racer that would only bore the block .002-.004 to clean the bore & then would have custom pistons machined to that bore , his block could last decades even doing regular rebuilds
 I would do a 360 , 10:1 Compression , port a set of 308 casting 88-92 heads pick a good cam [Solid or Hyd ] & intake like the EDddy RPM AIR GAP  , run a 750 Holley or Proform carb , run a windage tray , Double roller timing Chain & a set of TTI or Dougs headers , or Hoooker Super Comp & if you have more $ available a stroker kit up to 412 CI

Challenger - You`ll wish You Hadn`t

Offline femtnmax

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Re: 340 Rebuild advice
« Reply #3 on: December 25, 2008 - 10:39:30 PM »
I had a 340 duster many years ago. Super Yellow with black stripes and 340 logo on the rear quarters.  Could not afford a proper rebuild.  Cylinders were worn .005-.008 taper.  I put a set of rings in it, plus rod/main brgs, time chain, and a neway valve job w/o new guides (used the old valves).  Was lucky to afford that at the time.  I knurled the pistons-which was a TOTAL waste of time.. don't do it!!!   The car was drove hard by me for years afterwords, never did have any issues with it, though I'm sure it started to use oil before another 40-50,000 miles.
I finally sold the car to an oil rig worker headed for Alaska.  I saw him years later.. Said everywhere he went was at 100 mph- even up the alcan highway.  He pounded the car so hard that one trip north both front frame rails cracked and he limped into Anchorage.  Had the K-frame welded to the unibody trying to hold it together.
So long story short. Budget builds can be done, and can be made to last, though I would not recommend it.
EVeryone is so into this matching numbers stuff.
If you got all sorts of money I guess.  My cars are all drivers.   My skis go anywhere on the mountain, not just the pretty groomed runs.  I know a guy in Wichita that drives to work one day every week in is hemi cuda or charger daytona in full nascar paint/decal trim.   A friend just last summer drove his GTO from Idaho to Palmer Alaska:))   Cool!!   Its great to see folks still getting them out on the roads, not just a trailer queen to the Arizona car show.
Phil

Offline Changin Gears

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Re: 340 Rebuild advice
« Reply #4 on: December 26, 2008 - 07:57:21 AM »
:iagree:
 I would NEVER bore a block if it didn`t need it but most do ust to get the clearances back & get the cylinders straight
 I remember reading about a SS racer that would only bore the block .002-.004 to clean the bore & then would have custom pistons machined to that bore , his block could last decades even doing regular rebuilds
 I would do a 360 , 10:1 Compression , port a set of 308 casting 88-92 heads pick a good cam [Solid or Hyd ] & intake like the EDddy RPM AIR GAP  , run a 750 Holley or Proform carb , run a windage tray , Double roller timing Chain & a set of TTI or Dougs headers , or Hoooker Super Comp & if you have more $ available a stroker kit up to 412 CI

This is the build I would do, lot of bang for the buck here.


The goal never changes - Stop the 60' timer with your back tires

Offline 71chally416

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Re: 340 Rebuild advice
« Reply #5 on: December 27, 2008 - 02:32:33 AM »
 :iagree: I'm down with all that.

And by all means go with bigger Intake valves. Mancini sells complete seats of SS 2.02"/1.60" valves with single grooves for $160 that are the preferred nail head design. I'll never figure out why Chrysler used Tulip intake valves on the old small blocks.  And don't let a hack do the valve job and sink them into the chambers. Nothing will kill the port flow quicker. The whole margin of the valve head needs to stick above the valve seat/chamber to get good low lift flow. I know that's the problem with many motors that run poorly for no other apparent reason because I rarely see a valve job I like. Either the seats have too much runout or they have a big topcut to narrow the seat width because of careless machining or because they tried to get rid of seat runout. If you see a big machined area around the valve heads with the heads assembled, they are sunk, and so is your head flow. Get some that aren't.
Once we had Ronald Reagan, Bob Hope & Johnny Cash. Now we have Obama, No Hope and No Cash!

Offline William H Meister

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Re: 340 Rebuild advice
« Reply #6 on: December 28, 2008 - 02:14:21 AM »
Great advice..I'll keep you posted on the restorations board.

Bill