1978 Mustang Will a chevy 305 fit in it

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jozsefsz

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Aug 11, 2013
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1973's not a II, you might wish to ask in another forum. Though your title states 1978 so I'll assume that. A 305's a few inches wider than a 302 so it would be a very tight squeeze in a II (and finding some very narrow headers may also be a challenge) without more substantial modifications. A 1973 has a substantially wider engine-bay. Then you're into oil-pans, transmission configurations, etc. I'm sure anything can be engineered to fit, but as you're a new member and I know nothing about your background, and you're asking a question best asked by doing a lot of googling and measuring, I'd say no it definitely isn't going to be an easy fit. If you have a 305, sell it and pick up a nice H.O. 302.
 

74stang2togo

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I was wondering if a Chevy 305 engine will fit in a 1973 Mustang?
You've got 1978 in the thread title, and 1973 in the thread body. Those are totally different cars other than most of the name and the manufacturer. It could probably be made to fit either one, but as @jozsefsz said, the '73 would be a lot easier out of those two.

That said... why?

A Chevy 305 has zero advantages over pretty much any other engine in the history of engines. It provides all of the weight and fuel economy of a Chevy 350, all of the performance of an 80s-90s Chevy V6, and isn't even a good starting point for performance upgrades due to it's unique bore, weak crankshaft, and relatively small displacement and low redline.

Objectively, all of the other Chevy small-block V8s except the 4.3L smog-era V8 and the original 265 with no oil filter and block-front mount bosses are superior to the 305. Hell, objectively, so are all small-block Fords except the 255, and all small-block Chrysler V8s.

Even if the Chevy 305 is free or already on-hand; financially it's a bad decision as well, because you'll be looking at a lot of custom and one-off pieces that you'll either need to fabricate yourself (and if you're asking us instead of just doing it, I'm going to assume you don't have the tools and knowledge), or pay someone to make.

If you have a Mustang with no engine, and the Chevy 305 engine, the smart decision it to sell one or the other and find something compatible with the one you keep. This is a Mustang site, so suggesting to keep the Mustang would be a bit obvious, but to be honest, if I had a running 305 and could offload the Mustang more easily with the result being enough funds to buy something cool like a '67-80 GM pickup to drop it into (somewhere a 305 would actually be a pretty decent choice, as it's got enough displacement to be torque-y enough for the job, and will still sound great with a set of headers and dual exhaust, and most of it's limitations don't really hold it back), I'd totally keep the 305; otherwise, well, then the obvious choice for a Mustang site is obvious.
 

Nm22

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Oct 12, 2018
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1973's not a II, you might wish to ask in another forum. Though your title states 1978 so I'll assume that. A 305's a few inches wider than a 302 so it would be a very tight squeeze in a II (and finding some very narrow headers may also be a challenge) without more substantial modifications. A 1973 has a substantially wider engine-bay. Then you're into oil-pans, transmission configurations, etc. I'm sure anything can be engineered to fit, but as you're a new member and I know nothing about your background, and you're asking a question best asked by doing a lot of googling and measuring, I'd say no it definitely isn't going to be an easy fit. If you have a 305, sell it and pick up a nice H.O. 302.
Sorry about that I typed that wrong.
 

LILCBRA

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I dunno, from what I remember the 307 was a complete turd compared to the 305? :jester:

I know an 85 TA with a 305 was largely outmatched by a comparable 85 GT (speaking from experience driving the GT against a family member with the TA....)

I'll third the "trash the 305 in a Mustang" sentiment. If you must go with a GM powerplant, at least go with a 350 base or go with an LS, I believe you'll be happier in the long run. If $ is a concern, you'll most likely be money ahead trying to find a Ford 302, but there again it all depends on what you have for a car too. If it's an originally equipped V8 car, you hopefully have all of the necessary components to facilitate the installation. If it was a 4 or 6 cylinder, you're gonna need to find motor mounts, most likely an oil pan, headers or II specific manifolds, and a small enough bell housing and flywheel/flex plate for the transmission you plan on running. That's just the "big stuff" off the top of my head - I'm sure there's some smaller stuff that will need to be sourced to add to the bill. As I'm sure you already know or have been told, you can do pretty much anything with enough money, how deep are your pockets and what is your end-goal? Basically, bastardizing any car with an engine from a different manufacturer is going to take fabrication and, if you're not capable of doing so yourself, fabrication takes money - and quite a bit of time to iron out different problems that arise. The old saying "time is money" is completely accurate in this scenario! Good luck with whatever you decide!
 

74stang2togo

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I dunno, from what I remember the 307 was a complete turd compared to the 305? :jester:
The Chevy 307 was just fine. It was a 327 crank stuffed in a 283 block from the factory. A friend in high school had a Chevelle with one.

The Oldsmobile 307, which shared it's "reign" with the Chevy 305 was every bit the turd the 305 was.
 
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LILCBRA

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I don't remember too much about them honestly. All I really have to go from was one of my uncles also had a Chevelle with a 307. When it broke down, my other uncles just kept razzing him about getting a car with a 307. That was really the only time I've even knowingly seen one in anything, everyone seemed to always have a 350. So much so that they just don't impress me much either. There were plenty of people back in the day who had a 350 in their Camaro or whatever who I'd end up waxing on the street with my 302. There were some good ones out there at the time, but by and large they were all turds! I'd always get a bit of a chuckle when they'd look down their noses at my II to only get beaten by it afterward. Nowadays it's not really all that fast comparatively, but back in the day it would hold it's own in stock form and it only improved with a stock 302 from a 68 Cougar. The rest, as they say, is history! :)