I.D. 340 parts

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67GTConvert

67GTConvert

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I picked up a disassembled 340 today which the owner did'nt have any history on except he was under the impression that the motor was original to his car which it was'nt.I'm not sure about some of what came along with it so hopefully someone on here can shed some light on it.

The motor is a cast crank 73 with one '3418915-G' 'J' head (two 'J's by the spark plugs) and another head with a 'J' on the underside but not by the plugs and has a different casting # (3671587-E).Is that basically a later version of the same head? The intake ports measured out the same and both appear to have similar valve sizes which appear to be 2.02 intakes and 1.60 exhausts but I was'nt able to measure them too exactly.

Also included was an edelbrock D4B which I'm not familiar with.I measured the ports and they're the same width but shorter than the ports on the head.Is that intake built for 318 size ports? It's a high rise piece and looks like it should flow decently.
 

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Sounds 73-ish, with an aftermarket intake that is similar to today's Performer. Nothing super special about the intake. Having the two different heads on a 73 isn't completely unusual, but having 2.02" intake valves is. It's almost 40 years old. Most likely some work and swapping has been done.
 
Greg.. the "D4B" is the early version of the "LD4B" ("L" standing for late), which has the small 273/318 ports. If you have 340/360 heads with the larger ports, the "LD340" is the intake you want.
 
I believe the intake is actually and LD4B, the "L" might have came off, 340 intake from what I remember. 3418915 are 340 j's. No guarantees with what I say though.
 
I'm also wondering if the bores and pistons are oversize.I found a "40" stamped into each piston top so I think they might be .040" oversize which means the block has been overbored already.There's also what looks like a date casting on the inside of them which is a "76" on the top line and "428P" below that.Anybody know if these are aftermarket pistons? Maybe from 1976?

The cylinders have a real slight ridge and some light scratching so I'm hoping I could get away with just re-ringing it but ideally it should probably get bored out with new pistons.Can you go .060" over on 340 blocks? I'm not planning an all out race motor,just a stock style redo.
 

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damnimcooltom said:
Sounds 73-ish, with an aftermarket intake that is similar to today's Performer. Nothing super special about the intake. Having the two different heads on a 73 isn't completely unusual, but having 2.02" intake valves is. It's almost 40 years old. Most likely some work and swapping has been done.
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I kind of suspected the valves may have been upsized or maybe one or both the heads are from 71.I'll have to find out what years those castings are from.I've heard of the '915' 340/360 head but the other casting I'm not sure about.
 
65Val said:
Greg.. the "D4B" is the early version of the "LD4B" ("L" standing for late), which has the small 273/318 ports. If you have 340/360 heads with the larger ports, the "LD340" is the intake you want.
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Thanks for the clarification on that Darwin.Maybe I could use that intake on my 273 for now instead of the stock heavy iron 4 bbl one that I was going to use.
I should measure the ports on the '302' heads and see if they're a close match or just bolt it onto the stock heads and see if it wakes it up a bit.

I've heard the LD340s are a really good intake.I see a couple advertised on here so I should probably scoop one up.I just want to build up a nice mild 340 for future use in the Dart so that intake would probably work really well and look period correct.
 
67GTConvert said:
Thanks for the clarification on that Darwin.Maybe I could use that intake on my 273 for now instead of the stock heavy iron 4 bbl one that I was going to use.
I should measure the ports on the '302' heads and see if they're a close match or just bolt it onto the stock heads and see if it wakes it up a bit.
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The intake bolt angle and size are going to be for the early 273 ('64/'65)...small bolts and diff. angle to match the early heads. The mounting faces are the same,though. It can be made to work on your '67 273 (stock or "302" heads) by judicious use of a drill.
 
I looked up the casting numbers for the heads and the 3671587 is the correct head for a 73 340 and was also used on 73-74 and 76 360s.

The 3418915 would have been from a 71-72 340 engine or a 70-72 360 so it would be the one that's been replaced along the way.

I wonder if there's any difference beetween the two...I'll have to do some more digging.
 
65Val said:
The intake bolt angle and size are going to be for the early 273 ('64/'65)...small bolts and diff. angle to match the early heads. The mounting faces are the same,though. It can be made to work on your '67 273 (stock or "302" heads) by judicious use of a drill.
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Thanks again for the heads up.
I just had a quick peek and it looks like someone might have made them to work with the later heads going by ovaling the holes on the cylinder head end.It does'nt look like too brutal of a job and some of the holes have fairly deep thread marks inside them so they could possibly need a bit more material taken off.
 
67GTConvert said:
Thanks for the info.10-1 compression sounds pretty healthy so hopefully I can keep those pistons and just re-ring them.None of them were labeled which cylinder they came from so I probably don't want to use the old rings again.
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Greg...you don't want to reuse the rings regardless. Get the bores mic'd and checked for roundness. If they check out, then you'll want to go ahead and have the holes honed, or at least scuffed to allow the new rings to seat. You can get .040 "File-fit" rings that are slightly bigger than stock .040 rings that may allow you to use your current pistons.

None of them were labeled which cylinder they came from
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Check the big end of the rods for cylinder numbers.

Just a start.....
 
65Val said:
The intake bolt angle and size are going to be for the early 273 ('64/'65)...small bolts and diff. angle to match the early heads. The mounting faces are the same,though. It can be made to work on your '67 273 (stock or "302" heads) by judicious use of a drill.
Click to expand...

You ought to sell that D4B intake to one of the guys here, that have 64-65 small port heads. I'm sure you can get what you want with the money. You can get it bolted on to newer heads but the angle is different also so your bolts are not pulling straight, but cocked. My 2 cents. It is of course your decision.
 
Those piston valve relief depths don"t look like any 10:1 piston I ever saw????????????
 
dustoff440 said:
Those piston valve relief depths don"t look like any 10:1 piston I ever saw????????????
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A previous poster had a link to a site which sells those pistons (Sealed Power) and the part number and description matched up so I'll go with that for now.

It sounds like they're a stock replacement piston for the earlier 340's but with slightly lower compression for todays gas and they're also good for upgrading the later low compression 340s which this one would have been.
 
66fs said:
You ought to sell that D4B intake to one of the guys here, that have 64-65 small port heads. I'm sure you can get what you want with the money. You can get it bolted on to newer heads but the angle is different also so your bolts are not pulling straight, but cocked. My 2 cents. It is of course your decision.
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Are you looking for one? I'll be looking for a LD340 intake so I'd be interested in trading or would sell it for what the going rate on one of those is.
 
green1 said:
you need to mike the bores; those pistons look like no oil changes for 150,000 miles.
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I have'nt miked the bores yet but there is very little ridge at the top of the cylinders so it might not need another overbore,I hope.

The rest of the engine internals are pretty clean but yeah,the piston tops are pretty grungy.I think the carb might have been running pretty rich as a lot of it seems to be carbon but some is probably burnt on oil.
 
65Val said:
Greg...you don't want to reuse the rings regardless. Get the bores mic'd and checked for roundness. If they check out, then you'll want to go ahead and have the holes honed, or at least scuffed to allow the new rings to seat. You can get .040 "File-fit" rings that are slightly bigger than stock .040 rings that may allow you to use your current pistons.


Check the big end of the rods for cylinder numbers.

Just a start.....
Click to expand...


You're full of great ideas,I should have just contacted you directly...:-D
 
67GTConvert said:
Are you looking for one? I'll be looking for a LD340 intake so I'd be interested in trading or would sell it for what the going rate on one of those is.
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I am not looking for one, but good "64" and "65" 273 4 barrel Intakes are hard to find, and that was one of the best. I'm sure a lot of guys on this forum would love to get a chance to get one. For you, the ports are too small and the bolt angle will put a bending moment on your intake bolts. They should pull straight. Good luck, nice find.
 
66fs said:
I am not looking for one, but good "64" and "65" 273 4 barrel Intakes are hard to find, and that was one of the best. I'm sure a lot of guys on this forum would love to get a chance to get one. For you, the ports are too small and the bolt angle will put a bending moment on your intake bolts. They should pull straight. Good luck, nice find.
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Thanks for the info and advice,selling it on here to someone on here with an earlier 273 then using the money for an LD340 does make the most sense.
There's been a few listed lately so I'll check for availibility then list if for what the best price on an LD340 is.
 
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