340 crate motors / was dropping SB oil pan in car.

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Neal Zimmerman

Neal Zimmerman

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When I bought my car, the owner said the original 318 was yanked in the eighties and replaced with a "crate 340" and it probably has less than 30k miles on it ("yeah right buddy" ). Was there such a thing in the eighties? Thought the 340 died in 1973.
I put the motor on stand to pop heads and pan and see what my cam sprocket nightmare damage did. First thing I noticed was block said "70", and I knew it was a steel crank motor from the balancer. when I popped heads and cleaned off a piston top there was no overbore stamping on piston, and ring ridge is almost not there. So I started to think "well maybe he was telling the truth after all". When I popped the pan and inspected oil pump, and a rod and main I would say bearing condition was average, although I am no pro. but I am still baffled by this "crate motor" thing. Were they available with virgin bore from the dealer or direct connection?
Neal
 
Yes, as a matter of fact you could buy brand new 340s right from Mopar Performance or Direct Connection up until just a few years ago. Long blocks, short blocks, or complete engines.
 
You could also get them from PAW (Performance Auto Warehouse) ten years ago before they exited from the Mopar line of performance parts.
 
Check for a partial VIN, down low on the passenger side. If it has one, the crate it came in was a car.
 
I believe automakers have to provide parts for ten years after the last model year so 1983 would have been the last legal year to get a replacement engine from a dealer parts counter.
 
OK, good lead. I will check for a VIN number on block.
As for the prognosis of motor, took it to my guy today and verified, yes its original bore (mic'ed it out) but no its not 30k motor. He said the pistons are right at the edge of a bore job, so were gonna go ahead and bore it with new slugs. A few of the exhaust seats are sinking so all the exh. valve seats will be replaced. we're gonna put a different cam in it. He said he can order several brands right in the engine kit and save me dough-( Comp, Crane , Mopar Performance, Edelbrock). Any cam preferences , folks??
He said if anywhere to spend extra money, its in the rocker arm assembly. He seems to have a low opinion of mopar rocker assemblies.He's gonna price out rollers.
I am not building a motor to go to the nationals, just a peppy street car, although I am now toying with the idea of pulling that a-body four speed setup out from under the bench and sticking that in, while everything is apart.
neal
 
The replacement rockers arent gonna be 1.5, more like 1.45. However the shaft and rockers are quite durable and stable. I put a comp roller rocker setup in only because of the cam lift. Nothin wrong with the factory design. Congrats on the nice score.
 
Neal Zimmerman said:
why are replacement rockers only 1.45, instead of original 1.50?
Click to expand...


Because they are stamped steel. You can use 273 rockers. I would NEVER use a rocker with a needle bearing on the shaft. I know its been done forever but its still wrong. There a many good rockers out there that dont have needle bearings on the shaft. Any of those will work.

Just contact Mike at B3 racing engines and get the rocker arm geometry sorted out. They ALL need to have it done. His website is very usefull. Check it out.
 

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