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340 TA motor rebuild questions #2716834
11/17/19 07:16 PM
11/17/19 07:16 PM
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Michigan, USA
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sixpackman Offline OP
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sixpackman  Offline OP
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Michigan, USA
Hello,

I have a 1970 AAR 4 speed car and I'm in the process of building my 340 TA motor for it. My current bottom end is out of a 1973 340 motor. From what I've read a 340 4brl and a 340 TA internals are exactly the same except the TA has a forged crank and solid lifters and the 4brl has steel crank and hydraulic lifters??

Are this statements correct? Any specifics on a TA motor would be greatly appreciated!!!

340 TA - CAM lift and duration?

Thanks,
Scott

Last edited by sixpackman; 11/17/19 07:22 PM.
Re: 340 TA motor rebuild questions [Re: sixpackman] #2716836
11/17/19 07:25 PM
11/17/19 07:25 PM
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Hamtramck, PA
Alaskan_TA Offline
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Original T/A engines had manually adjustable hydraulic lifters.

All 1970 340s regardless of carburation had forged cranks.

Re: 340 TA motor rebuild questions [Re: sixpackman] #2716855
11/17/19 07:43 PM
11/17/19 07:43 PM
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Banana Republic
FM3AAR Offline
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The 340 6 BBL used the 340 4/BBL cam.

Wiki had a good write up: https://en.wikipedia.org/wiki/Chrysler_LA_engine

"340 V8
Mopar 340 cu in (5.6 L) Small Block
In the mid-1960s, Chrysler decided to adapt the 318 cu in (5.2 L) small block V8 into a lightweight, high output engine equally suited for drag strip or street performance use. Its block was bored out to 4.04 in (102.6 mm) but 3.31 in (84.1 mm) stroke left unchanged, resulting in the 340 cu in (5.6 L) engine. Anticipating higher loads resulting from racing operation, the engineers fitted a forged shot peened steel crankshaft instead of the cast nodular iron unit used in the 318. This also included shot peened and forged pushrods, connecting rods and pistons. A 4-barrel carburetor was mated to a high-rise, dual plane intake manifold feeding high-flow cylinder heads that are still considered among the best of that era.[citation needed] Its big ports used 2.02 in (51 mm) intake and 1.60 in (41 mm) exhaust valves. An aggressive cam was fitted to take advantage of the much better breathing top end. The 1968 4-speed cars got an even hotter cam, but it was discontinued for 1969, where both automatic and manual cars shared the same cam. The engine was equipped with hydraulic lifters and two bolt main bearing caps, leading some to initially underestimate the 340's potential. The 1968-'71 340's compression ratio was 10.5:1, placing it near the limit of what was possible on pump gasoline during that era. The 340 also used additional heavy-duty parts, such as a double-row roller timing chain and sump-mounted windage tray. Power output was officially stated as 275 hp (205 kW) gross for the 4 barrel.

In 1970, Chrysler offered a special Six-Pack version of the 340 with triple 2-barrel carburetors rated at 290 hp (216 kW) gross that was specific to Challenger TA and Cuda AAR models. This version featured a heavy duty short block with additional webbing to allow for aftermarket installed 4 bolt main bearing caps. The application-specific cylinder heads featured relocated intake pushrod passages with offset rocker arms that allowed the pushrods to be moved away from the intake ports, which could improve airflow if the pushrod-clearance "hump" was ground away from the intake port by the end user. An aluminum intake manifold mounted three Holley carburetors, and a dual points ignition system was fitted.

The combination of rising gasoline prices and insurance company crackdown on high-performance vehicles saw the relatively expensive 340 detuned and phased out. It remained a high performance engine through 1971, but was de-tuned in 1972 with the introduction of low compression (8.5:1) small valve heads, and by mid-year, a cast nodular iron crankshaft, and a variety of other emissions related changes. For the 1974 model year it was replaced by the 360 cu in (5.9 L) engine."


“You’ll own nothing” — And “you’ll be happy about it.”
K. Schwab



Re: 340 TA motor rebuild questions [Re: sixpackman] #2716894
11/17/19 08:58 PM
11/17/19 08:58 PM
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Bend,OR USA
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Cab_Burge Offline
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The AAR and T/A blocks, heads, rocker arms, pushrods, intake system are for those motors only, the rest of the internal parts like the rods, crank, pistons, lifter and camshaft and timing set, oil pan, timing cover, valve covers and so on are the same up
If you don't have the original block and want one I may know where one is work
PM me on here If so up


Mr.Cab Racing and winning with Mopars since 1964. (Old F--t, Huh)
Re: 340 TA motor rebuild questions [Re: Cab_Burge] #2716940
11/17/19 10:04 PM
11/17/19 10:04 PM
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ontario calif
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ns1aar Offline
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OEM lifters are T/A only 3577092 and pushrod 3577121

Last edited by ns1aar; 11/17/19 10:07 PM.

NS1AAR
Re: 340 TA motor rebuild questions [Re: ns1aar] #2716997
11/18/19 01:26 AM
11/18/19 01:26 AM
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Bend,OR USA
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I've never heard that about the lifters, I had a 1970 T/A motor that I replaced the cam and lifters with a solid lifter cam. I should have save them but that was back in the mid 1970s shruggy
The NHRA tech sheet on those motors listed the lift and duration as the same for the 1968 to 1971 340 4 barrel motors shruggy
I wonder if they have the same part number as the 1969 440 6 pack low taper hydraulics lifters?

Last edited by Cab_Burge; 11/18/19 01:27 AM.

Mr.Cab Racing and winning with Mopars since 1964. (Old F--t, Huh)
Re: 340 TA motor rebuild questions [Re: Cab_Burge] #2717020
11/18/19 07:27 AM
11/18/19 07:27 AM
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Abilene, Texas
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fastmark Offline
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The crankshaft in your car right now could be a forged steel shaft. You can’t tell unless you look at it. A lot of the 72-73 340 cars still had a forged steel crank in them if they were a four speed. Look at your balancer on the front. Does it have the offset for the external balanced engine?

Re: 340 TA motor rebuild questions [Re: sixpackman] #2717034
11/18/19 08:46 AM
11/18/19 08:46 AM
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Florida
Locomotion Offline
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Originally Posted by sixpackman
Hello,

I have a 1970 AAR 4 speed car and I'm in the process of building my 340 TA motor for it. My current bottom end is out of a 1973 340 motor. From what I've read a 340 4brl and a 340 TA internals are exactly the same except the TA has a forged crank and solid lifters and the 4brl has steel crank and hydraulic lifters??

Are this statements correct? Any specifics on a TA motor would be greatly appreciated!!!

340 TA - CAM lift and duration?

Thanks,
Scott


There's about 2 points difference in compression between the two! 340's had an advertised rating of about 10.5-1 until 1972 when they dropped the compression to an approximate advertised 8.5-1, all in the pistons.

Never heard about the special lifters, but they were hydraulic and the pushrods were about about 7.23" compared to 7.5 for the 273 solid lifter pushrods with adjustable rockers. There is a difference in cup height between a hydraulic & solid lifter.

I believe 1972 was the transition year from forged to cast crank.

Heads were 915 castings (like a 360), but had the 2.02" intakes & offset pushrod holes. However there was a limited run of 894 heads for it. Apparently to get around certain race related rules, not OEM. Talked to the owner of unedited pics of unaltered heads on another site.

Last edited by Locomotion; 11/18/19 08:54 AM.
Re: 340 TA motor rebuild questions [Re: Cab_Burge] #2717715
11/19/19 10:02 PM
11/19/19 10:02 PM
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Posts: 1,144
ontario calif
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ns1aar Offline
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Originally Posted by Cab_Burge
I've never heard that about the lifters, I had a 1970 T/A motor that I replaced the cam and lifters with a solid lifter cam. I should have save them but that was back in the mid 1970s shruggy
The NHRA tech sheet on those motors listed the lift and duration as the same for the 1968 to 1971 340 4 barrel motors shruggy
I wonder if they have the same part number as the 1969 440 6 pack low taper hydraulics lifters?

440 6bbl lifter part number is 3420039


NS1AAR
Re: 340 TA motor rebuild questions [Re: Cab_Burge] #2717740
11/20/19 12:16 AM
11/20/19 12:16 AM
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North Pole,New York
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formula_s Offline
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Originally Posted by Cab_Burge
The AAR and T/A blocks, heads, rocker arms, pushrods, intake system are for those motors only, the rest of the internal parts like the rods, crank, pistons, lifter and camshaft and timing set, oil pan, timing cover, valve covers and so on are the same up
If you don't have the original block and want one I may know where one is work
PM me on here If so up



The Valve Covers are not the same.

Re: 340 TA motor rebuild questions [Re: formula_s] #2717758
11/20/19 03:29 AM
11/20/19 03:29 AM
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Bend,OR USA
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Cab_Burge Offline
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All the ones I remember seeing, I'm a hot rodder, street and strip drag racer,not a restorer or show car guy, all looked alike on the AAR and a T/A cars I saw in the early to mid 1970s. shruggy
All the T/A and AAR ( 6 to 10 maybe) 6 pack motors ran a lot better than the stock 340 AVS carb motors that I drove did regardless of body style, A or E bodies shruggy
Mopar built those cars so they could compete in the Trans Am racing that was hot back then against the Camaro, Firebirds, Mustangs Cougars and the AMC cars that ran in that series.
They weren't very popular and where hard to sell to the hot rodders and they would sit on the lot longer than the other brand Hi Po models back then shruggy

Last edited by Cab_Burge; 11/20/19 03:30 AM.

Mr.Cab Racing and winning with Mopars since 1964. (Old F--t, Huh)






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