Hey guys, I just picked up and brought home a complete and running 340/904 tranny setup I bought on ebay. Anyway first I noticed the intake had some light porting under the carb, then I took off the valve covers to find some pretty hard core setup that I havent seen before. Now they are J heads and the motor is block #
2780930 340 5 and date coded 7 2 70. But there seems to be dual springs with dampers, non-steel retainers( any ideas) and big aluminum blocks for bolting down the adjustabe rockers. Also if you look down the head into the block there is a big aluminum plate with holes for the pushrods that I've never seen before.

So can anyone tell me anthing about this setup? It was soposedly a good running motor but I'm gonna tear it down to inspect and see what else lies beneith, but I figure maybe someone can help me out on this one. Heres a few pictures.

Butch

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If the retainers are aluminum, recycle them ASAP before you have to recycle the whole engine. If they are titanium retainers, you're fine.

The blocks were a valvetrain trick to help geometry, usually with long stem valves and/or get clearance for larger diameter valve springs. Milled rocker shaft pads were standard on race W-2 heads. Econo W-2 had OEM-style cast stands.

Double-check the rocker contact patch on the valve to make sure it's not to far inward towards the shafts.

The plate inside may be a Milodon or similar valley tray that has a pair of spring steel straps that snap under the heads. It keeps the lifter in its bore in case there is a valvetrain failure. Otherwise, a lifter popping out could cause rapid oil pressure loss.

The intake looks like an original Edelbrock Torker or Tarantula intake. My personal opinion is that either one is junk compared to what is available today.

I also just noticed that the oil squirt holes on top of the rockers have been closed off with a set screw!

Do the hold-down bolts go through the middle of the rocker shaft or is the shaft offset towards the intake?

Intersting set-up. I'm curious what's inside too!
This should probably be in the Unlawful's Race Only section.

Are you sure those are J-heads? What is the casting number? Also, could you take a photo of the numbers on the front of the block under the drivers head and post it? (see example)

VIN from the pad on the passenger side of the block too please?

Ok, first is there a way to tell if the retainers are aluminum or titanium, looks like this motors seen a good amount of use and there still looking good. And your right on the blocks, the rocker shaft mount was milled down, the bolt goes throught the rocker shaft and block and into the head where it normally bolts up, but with larger bolts. Ans your also right on the valley pan , I took the intake off and it is held on with 2 spring straps, so your probably right there too.

Well I got the intake off and pulled one head, they are indeed J heads, with what looks like stainless 2.02 intake and exhaust valves. Looks like they did some heavy port matching as the intake port on all of them hit the valve cover bolt area in between intake ports.

Also after pulling the heads I found TRW .030 over L-2322 forged dome pistons. The cylinder walls look great, there isnt even a ridge on top once I wipe away the carbon, and I can still see cross hatch. Strange thing is, that there is no notable bore scorring or were, but the pistons are really loose in the bore, but I was able to see one top ring gap and by eye it looks good. Now heres the other thing, the pistons look like the valve reliefs were cut deeper, and thy must have cut too deep on one, cause a couple chunks are missing. But with the piston with the missing peice, the walls look great and there no chunk in the bore, and it looks like it has been runn for a long time like this?

So heres a few more pictures, what do you think, can that one piston be run like that, well it was running so I quess I answered my own question. But why would pistons be run so loose?

Butch

Ohh yeah the drivers side front block # is

G340P33750547 then theres a 43 with a 3 under thats stamped sideways

And the heads are AAWJ
3418915(G or C cant tell)

Rocker shaft boss...

More

71 model year 340 built around Oct 24, 1970

Those pistons look like the old TRW 12.5:1 slugs.

Valley pan,,,

Looks like you left a letter out after the G? At any rate what you posted breaks down as a:

G-Series (1971 model year) 340
P = Premium Fuel
October 24th 1970 Assembly date
547th engine assembled

Cool engine, but you better have lots of race fuel around with those pistons, that is one old school build! IMO I'd tear it down and start over with all fresh parts, pistons, rockers, etc. Maybe even the heads if those have been overly ported.

Those valve releifs have been machined deeper than my set of the same pistons, that is why they broke through on the ring lands. Those pistons are not too high of compression with stock heads, they don't come in anywhere near what they are suposed to unless the heads or deck have been milled a lot.

Looks old school, and OLD, go over everything with a fine tooth comb.

Ok heres another picture of the damaged piston.

And heres a good shot where you can see how loose it is, look at how much ring you can see on the sides, now keep in mind that this motor is filthy on the outside and going by the gaskets, hasnt been apart in a long time, looks like since it was built. What would be the reason for such loose pistons.

And heres how far the pistons stick out....

Now this was a running motor, I didnt see it in person, but the guy took video of it running before he pulled it out of his 64 Barracuda. I got the whole setup for the rediculous price of $275. My plan was to just clean it up and drop it in my 72 Duster to replace the 318 in it now. It was ment as a temporary motor till I can save up to build a 408/416 stroker. Of cource I wasnt expecting all this crazy race stuff. Anyway now I have to debate on slapping it back together and running it or putting it aside to build something out of it, or just unload it in favore of a more steetable cheap engine.

Do you think its a time bomb with that one broken piston, and would it be able to be run with just octane booster? I plan on cc'ing the heads to get an idea of the true compression, and maybe running a thicker gasket.

What do you guys think.


Butch

Want to double your money?

Sell it (you'll make money) and run, that's a rebuild job or a bomb with a very short fuse.

Looks like they had done a ton of work on those heads. I'm guessing the valves are longer than stock so they could run some taller valve springs, for a really high lift cam, which ment they needed to raise the rocker arms and use longer pushrods.
It does look like they made the valve pockets too deep for those pistons.

Back in the day they used to run looser piston clearance in high performance motors. Also a piston is smaller at the top than the skirt area because the top gets hotter and expands more. I have seen quite a few motors where you could see the top ring a little much.

I would definately NOT run it with that burned piston in there. What bore size is it? I know where a few are sitting around . Since it is not really a quench engine any how you could run a thick gasket to reduce compression a little and get the needed valve clearance.

Quote:

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Ok, first is there a way to tell if the retainers are aluminum or titanium

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I have a set of these retainers that came with some T/A offset rockers and shafts that I just purchased.

I would also like to know how to tell the difference between aluminum and titanium. Mine don't seem to have any markings

So, I talked to the guy I got the engine from and he said he thinks it was running a 650 but not sure, and he was using either 89 or 92 octain fuel. He was unaware of the internals, but that probably explains the piston.

So my question is, what zize carb yould be good for this motor and what fuel would I have to run. Could I get away with a thicker head gasket and just running 93-94 plus octain booster, or am I gonna need a blend of regular and race fuel, if so what kind of ratio?

Butch

Thats a great old school build. Even better price!

Lots of work and money in those heads. (If done professionally)

Lot of valve spring for a hyd cam also.

Throw a piston, some rings and bearings in it and run it!!

Yeah the heads look like they were done right, with the exeption of breaking through to the valve cover bolt, but who knows it may have been done on purpose to open up as big as posible, doubt it would cause any issues.

I'm gonna try and locat a replacement piston and see what its got. I'm also gonna try to determine the lift and duration of the cam and see if something else might work better, seems like its screaming for a solid lift cam!!!!!

I'd be content if I could get away with just running a gallon or 2 of race fuel mixed in a tank, but if its too much more than that, I may have to rethink things as that could get pricy for a mainly street car.

I bet it would be fine with some new pistons just like those and some thick head gaskets, those pistons don't give any where near the compression they are advertised to give plus looks like a couple CCs are removed from the chamber also.

With an old school ong duration cam it can be made to run fine on pump gas.

Hmmmm, good to know. I still have to determine what cam it has, any sugestions of what would be a good cam for this setup, apparently lift is no problem....

What would I look for in a cam to bleed off preasure? Just long duration? I wouldnt mind a good solid cam.

Weird to think I've stood in the garage.


Hey Butch. Remember that young kid that pulled up in your driveway many moons ago in a white dakota with sidepipes?

Glad to see you're still around moparts and still plugging away at going fast

I would be worried that if 1 piston is broke, then the others may go too. If it were mine, and the walls look good, I would look at replacing all the pistons and maybe hit it wil a ball hone and get some new (or newer) pistons and run it. Pistons are fairly cheap nowdays and you can pick the compression you want. Then from there pick a cam and carb and your done......at least with the engine part.

Well I just pulled the other head and theres another pistons just like the one on the other side and 2 other pistons that look like they melted a little on the thin areas on the ousides of the deep vavle pockets, looks like a new set of pistons is a definate. Good news is that those cylinder walls look just as good, crosshatch and no ridge!!!!!

Strange thing is, I measured the lobe lift and got .295 on the intake and exhaust, so if there 1.5 rockers that comes out to .4425. Seems awfully low for all that crazy valve train mods and super deep cut valve reliefs. Wonder if someone poped in a new cam at some point hoping to make it more streetable.

Now correct me if I'm wrong, I placed a magnetic base in the valley and put the dial indicator on the cam lobe when theres no lift and zeroed it out. Then I turned over the engine till the lift stoped and it was at its peak. So that is a correct way to determine lobe lift is it not? Just checking.

Now I have to get my 360 off the engine stand so I can get this on it and see what the bottom end looks like. So it looks for now, that I'm looking at new pistons or used, I found a set of the same pistons that the seller is willing to mill down to my desired height so I may go that rought so the ballance is close. Then hopefully I can get away with just a hone, rings, and bearings barring the crank looks good, and a new cam.

Also noticed that the head chambers have been polished smooth so I'll cc the heads to see where I'm at. Hopefully I can still get this built with minimal funds and end up with a motor I can live with a loooong time.


Butch

Can you scratch the lifters with a screwdriver, Titanium is pretty hard. AL will scratch. Those rings will get preeety hot with no skirt around them, 2 replacements would be in order or just get some stock 10.5's. Heads look OK as long as the cover bolt break is epoxied or brazed. Nice score for under 600...

Cant scratch the retainers with a screwdrivers, there hard as nails, must be titainium, thats good news.

Well I beasured the pistons and the dome portion sits about .120 out of the hole while the top area above the valve reliefs sits at about .030 out. I saw a pictures of these pistons in stock form and they've definatelly been choped quite a bit.

Ok heres some new info, I cleaned up # 3 head chamber to cc the head and discovered that the chamber is fully smoothed and polished, real nice looking. Also I pulled an intake and exhaust valve, and they are definatelly longer then stock. They are Manley stailess valves with a 3/8 stem that tapers down by the valve head. The exhaust are 1.60 but I measured the intakes at a whopping 2.058!!!!!!!! My other J heads have stainless Miloden valves and they measure 2.023. So these 340 heads must be either 2.05 or 2.06, I've never seen such big valves in a small block. Also looks like under the valve in the bowl was ported as well. The valve guides feel tight and they had the positive seals. So it looks like the heads are in great shape.

So anyone know if these TRW 13:1(as stock) pistons can be cut down enough to get it down to 10.5:1 with a 62cc head? I found a set of replacements of the same piston, that the guy is willing to mill down for me, just dont know if they can be cut enough to get me where I need to be. Heres the head...

Heres another

bowl looks near stock, the guides haven't been touched. nothing to wild there.

Did you CC the heads yet? They don't look to be milled excesively, mabey a little

Scatpack, I havent pulled the pistons yet so I dont know that the clearence is down low.

HodRod, yeah I cc'ed them yesterday, and they came in at 62cc's which surprized me. I have another set of J heads with a 2.02 stainless valve and it cc'ed at 68-69cc's. I quess they were milled a decent amount, plus I'm sure the manley valves add to it not nearly as dished as stockers.