65 barracuda engine swap

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Baby huey

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Thinking about a 318 in place of my 273. Is there a problem with the stock transmission and rear end being able to handle this engine?
 
No, you should be fine with a stock motor. The 904 and 7.25 rear came from the factory behind a million 318s.
However, be aware of 2 issues:
The crank register of the 318 is larger than the '65 273- meaning you will need an adapter bushing in the crank in order to use the torque convertor from the '65. And you do need to use the '65 torque convertor, because the transmission input shaft changed size and spline count in '68(?).
If the 318 is '70 or later, the water pump inlet changed sides, meaning:
You will need a '70 or later style radiator
OR
You need to use the 273's timing chain cover and water pump on the 318.
Other things to be aware of:
If the 318 is out of a truck, the oil pan will not fit your Barracuda. Use the 273 pan/pickup/dipstick and tube from the 273.
Use all the throttle/kickdown linkages from the 273.
Member @Charrlie_S at one time supplied the needed adapter bushings- maybe he will chime in if he still does.
 
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Thanks for the info, I'm finding my 273, not the original engine anyway, parts are wow, a 318 is plentiful and cheaper so considering that..
 
I took the 318 short block and put all my spun rod 273/4's parts on and into it and it kicked more ***. 1/8" walled convertor bushing is required, it's available here from 2 members. You know that 'ol small register 273 forged crank will fit into that 318....IDK if it even needs to be rebalanced as the 273-2 pistons used some very heavy pins to make up the weight of the taller 273/4 pistons and their lighter weight pins. 318 piston+ rod assembly and the 273-2 piston+rod assembly was nearly the same weight.

273 piston connecting rod and wrist pin....1576g
318 piston connecting rod and wrist pin....1572g
(Thanks @MObarracuda )
 
On my engine, wierd thing is the engine ran sorta ok. When I broke it down I found the cam is no good, both heads are cracked, #4 cylinder has a deep rust gouge, don't know how that happened, as there was no leakage. And the #1 journal on the crank has a ding in it. So... i can't find 40 over pistons, 30 over are more than 600, have to buy 2 heads, I haven't looked at those yet, so... a 318 might be how to go.
 
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Baby huey said:
On my engine, both heads are cracked, #4 cylinder has a deep rust gouge, don't know how that happened, there was no leakage when I broke it down. So i can't find 40 over pistons, 30 over are more than 600, have to buy 2 heads so... a 318 might be how to go.
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Wow. Makes sense to me. You should have mechanical rocker arms, bushed rods, and a forged crank to save. The earlier the 318 the better.
 
Baby huey said:
Thinking about a 318 in place of my 273. Is there a problem with the stock transmission and rear end being able to handle this engine?
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That will depend on what kind of horsepower the replacement engine has. Stock 230 HP, they're adequate, not ideal, but, they'll work for a while. The transmission can be rebuilt to handle lots more horsepower, the 7 1/4 rear end......not so much. I'd round up a stronger rear end before you NEED one. I'd be more concerned about the braking system.
 
This is such great information, I really appreciate it. Update, I have a lead on another 273 already at a machine shop, we'll see where this goes.
 
Update... I've retrieved the engine. The block has been bored .60 over and pressure tested. That's all the work that was done.. It could be turned in to a hipo i guess, I'm not knowledgeable on that. So now....
 
Baby huey said:
Update... I've retrieved the engine. The block has been bored .60 over and pressure tested. That's all the work that was done.. It could be turned in to a hipo i guess, I'm not knowledgeable on that. So now....
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A hypo had high compression pistons and a little larger cam than the 2 barrel. The bolt on's were a dual point, a 4 barrel and intake, finned wrinkle finished valve covers and a chrome unsilenced air cleaner. They also had a larger single exhaust system with a stainless tip.
 
Dan the man said:
The pistons are expensive and harder to find, money ahead by going with a 318.
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Piston price do not bother me. I've had a HP 273 4 speed nearly all my life. I've also had 318s, 340s, 360s, and 383s. My favorite is a HP 273. If you never had one,it is hard to explain. Like 340's you can't go by the theoretical, or cost. Some things just work, and the money does not matter. Do it once and do it right.
 
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