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  #1  
Old 02-18-2008, 09:50 PM
petrol:head petrol:head is offline
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Default 273 bore out?

Hi all some help needed. My friend has just got a 273 lump off ebay it was posted as a 318 so was a little upset to find it was a 273 but on a stip down of the block found big valve heads double valve springs solid lifters cast 4 barrel intake I have found the stock bore sould be 3.63 [will check it] can I bore it out to 3.91 [318 size] or more and any other info would be great as to the best way to get grunt out of this lump Thanks all from UK.
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  #2  
Old 02-18-2008, 09:53 PM
3404spdvaliant 3404spdvaliant is offline
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I don't think so, say does it still have a steel crank?
Whats the casting # of the heads?
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  #3  
Old 02-18-2008, 10:06 PM
petrol:head petrol:head is offline
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Default 273

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Originally Posted by 3404spdvaliant View Post
I don't think so, say does it still have a steel crank?
Whats the casting # of the heads?
Will get back to you tomorrow when we take of the sump and give you all the numbers
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  #4  
Old 02-18-2008, 10:19 PM
bobr bobr is offline
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Quote:
Originally Posted by petrol:head View Post
Hi all some help needed. My friend has just got a 273 lump off ebay it was posted as a 318 so was a little upset to find it was a 273 but on a stip down of the block found big valve heads double valve springs solid lifters cast 4 barrel intake I have found the stock bore sould be 3.63 [will check it] can I bore it out to 3.91 [318 size] or more and any other info would be great as to the best way to get grunt out of this lump Thanks all from UK.

I'm definitely no expert on 273 blocks but I've never heard of a block that you could bore .280. -Bob
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  #5  
Old 02-18-2008, 10:42 PM
dave5711 dave5711 is offline
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Originally Posted by bobr View Post
I'm definitely no expert on 273 blocks but I've never heard of a block that you could bore .280. -Bob

Me either.
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  #6  
Old 02-18-2008, 10:49 PM
440roadrunner 440roadrunner is offline
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It doesn't sound like you have actually measured the block? For all we know, it might be "bored to the max" already.

I guess you've learned an important lesson. I certainly would not buy a block without demanding a pix of the block no. which tells the entire story.

(I could see this if it was a Chivvy)
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  #7  
Old 02-19-2008, 06:25 AM
petrol:head petrol:head is offline
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I see that no one has given any tuning tips or gainable Horse Power from this engine whats the best way to go all will post all casting numbers today.
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  #8  
Old 02-19-2008, 11:23 AM
3404spdvaliant 3404spdvaliant is offline
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Hey sorry I was distracted by the ''bore to a 318 question.''

Why not get some lighter replica 273 10.25 comp commando pistons and a little hotter solid cam than factory did like 276* .490 56* 0-lap.
Try and find & port some 318 heads cause the funky bolt pattern of 273 heads doesn't give you any options for intakes.
Seriously your gonna have to rev this thing to make good power so if you have steel crank you can so you might wanna go with the 360 rods w/full floating pins. The beaker rods will probably live and would keep rotating mass to a minimum but thats your choice.
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  #9  
Old 02-19-2008, 04:59 PM
petrol:head petrol:head is offline
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Quote:
Originally Posted by 3404spdvaliant View Post
Hey sorry I was distracted by the ''bore to a 318 question.''

Why not get some lighter replica 273 10.25 comp commando pistons and a little hotter solid cam than factory did like 276* .490 56* 0-lap.
Try and find & port some 318 heads cause the funky bolt pattern of 273 heads doesn't give you any options for intakes.
Seriously your gonna have to rev this thing to make good power so if you have steel crank you can so you might wanna go with the 360 rods w/full floating pins. The beaker rods will probably live and would keep rotating mass to a minimum but thats your choice.
Right the head cast numbers are 2658920 1967 there were also used on the 318 does that mean I can use 318 intake oh and It has a cast 4 barrel intake now cast number 2536563
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  #10  
Old 02-19-2008, 06:11 PM
Mecki Mecki is offline
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The factory 275 HP 273 used a 284* .510" cam and probably the intake manifold you already have. The intake manifold bolt angle was different in -64 and -65, from -66 on the heads and manifolds are all interchangeable.
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  #11  
Old 02-19-2008, 09:15 PM
3404spdvaliant 3404spdvaliant is offline
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The 920s are a closed chamber like the 234s I believe 57cc.
Might also be the heads with water heated cross over, Block this off.
As for what cam came in a factory 273 commando I don't know off the top of my head but It sounds like Meki is talking about the D dart 273 cam.
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  #12  
Old 02-20-2008, 09:26 AM
Mecki Mecki is offline
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Thats true, the 284* .510" was used in the D dart.

What was the HP rating for the commando?
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  #13  
Old 02-20-2008, 11:31 AM
3404spdvaliant 3404spdvaliant is offline
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I think it was 235-245 hp.
The cam wasn't that big like .435 after lash.
284* .510 sounds big for that little motor of course it only came in a 4spd car
which would be perfect for that cam.
I think the 276*.490 would work good in an auto car w/273 3.91 2400 stall
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