1968 340. What's inside?

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LXguy

LXguy

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Hey All:

Got a chance to add a full original 340 to my burgeoning collection of 340 parts.

Anyone know what a 68 340 has for internals? Forged pistons? Compression Ratio? X heads? Carb?

All I know is that it was in an automatic car, and its never been apart.

Thanks for any help!

Steve
 
68 is the best IMO, especially a stick car. I always felt the guys building them first year might take more time and get things better. Probably wishful thinking. But my first 340 was a 68 manual trans one.

It has cast flat tops with expansion limiters, forged crank, good rods, windage tray, X heads with 2.02 intakes, std exh seats and huge open chambers. Intake is the flat restrictive AFB version. Manifolds should be good hi-flows if included. True compression should measure out in the 9.7:1 range vs, advertised 10.5:1. '68 model year manual trans engines had a slightly knarlier cam in them, after 68 they all had the same cams.
 
Steve, in addition to what moper said, you'll also find full floating wrist pins holding the pistons to the rods. 340's were great little engines - kind of a 'Junior Varsity' hemi regarding power. I surprised many a 396-powered Chevelle with my '69 340 Swinger back then on Whittier Blvd.
Send it to me if you don't want it! LOL!!!
 

68 340
forged 3.31" crank
forged rods
forged pistons (4.04" bore)
x heads w/2.02, 1.60 valves
4 barrel intale
Carter AVS 625

underrated at 275 at 5000 rpm...they turned past 6 stock
 
hi, the 340 has a cast iron high rise intake on them!!! and had an AVS carb ,not a AFB!! also, has cast pistons, not forged. very underrated motor.
as a nhra stocker today, will run in very low 11 sec range.
 
Factory 68, 340 intake set up. Bad phone pics.....

4424S, AVS (4 speed)
2531915 Intake

DSC00024.jpg

DSC00023.jpg

DSC00022.jpg
 
Should be forged pistons, Comp ratio should be 10.5, should be X heads.should be a 625 cfm carter,First year of the 340. 275 hp.
 
Sounds like a great collectable. Just curious but, what is the date code on the motor?

Is the motor a 68 date code for a 69 car or is it late 67/early 68 date for a 68 car. I'm not 100% sure but I believe that the motor will be for a 68 car if there is a VIN# on the top back where the block meets up to the bellhousing. If its for a 69 car the VIN# will be on the ID pad on the passenger side near the front of the oil pan.
 
Hey Moper!

I have a 67 340 block with crank and cam.
Tell me, what did you mean by the cam being slightly knarlier????
 
danbud61 said:
Hey Moper!

I have a 67 340 block with crank and cam.
Tell me, what did you mean by the cam being slightly knarlier????
Click to expand...

Dan, the `68 manual transmission 340 came with a slightly larger cam with 276* intake and 284* exhaust with a .445/.455 lift while the auto transmission 340 had a 268/276 cam with .430/.445 lift.
 
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