Engine swap

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Bob D

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I have a 1965 barracuda with a 273 ci 180 hp LA904 . I’m thinking to swap it out the 273 with a 340 “ if I can find one”. My question is will LA 904 bolt up to the 340 block.
 
65 has a smaller crank register for the torque converter, I imagine there's some kind of spacer to make it work.
 
the engine will bolt up, but like 273 said you'll need to address the mismatch between the torque converter snout and the crank register.

i know somebody sells one, the last time i picked one up from wildcat autowrecking so you might try there? or you can have one made by a machine shop.

a concern would be the availability of performance torque converters for the early transmission. that being said, you could always send yours out and have it rebuilt to spec.

you'll need different motor mounts for a 340/360, the 318 are the same.
 
Decide what sort of horsepower you plan on having as you may want to upgrade a few other things too......such as a transmission rebuild, better brakes, and stronger rear axle assembly if those haven't already been done. You'll also need to figure out the best exhaust system for that setup too. The stock exhaust manifolds are a choke point and have mismatch ports with 340 heads. Chassis headers can get a bit pricey these days, but, cutting the inner fenders for headers have tire clearance problems and would make me cringe. :soapbox:
 
Headers are always better especially with higher overlap cams, but for mild 250-350 hp engine manifolds are fine.
 
66fs said:
I'm thinking 65 la 904 with the small input and torque converter hub. Probably better to go with a 68 up 318 or 360 904.
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He should sit down and think about the future. If it’s going to cruises and he wants to be able to say it has a 340 in it he’s good to go. If he’s planning to add horsepower in the near future and has the extra money now build for the future. I think Matt and I broke two 904 converter hubs and knowing their weakness we moved to 727’s. Back then a rebuild on a 727 cost me 275.00 or less.
 
pittsburghracer said:
He should sit down and think about the future. If it’s going to cruises and he wants to be able to say it has a 340 in it he’s good to go. If he’s planning to add horsepower in the near future and has the extra money now build for the future. I think Matt and I broke two 904 converter hubs and knowing their weakness we moved to 727’s. Back then a rebuild on a 727 cost me 275.00 or less.
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A 727 does not fit well in an early A. usually there are modifications to the pinch weld at the firewall. He said he wants to run 450 hp, I'd advise a newer stronger 904 in the early A. I also run 727 in everything 67 and newer, except my 4 speed cars which I prefer. I only have one 904 and it came from a 67 Commando car.
 
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