building 273..or not

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I'm not sure of this, but I think I heard that some early 273 2 bbl engines had a different intake bolt angle and the 4bbl intake won't bolt up.

Assuming it's a 2bbl. w/ stock heads.
 
My own opinion, it needs to be a labor of love to build a 273. Pistons and head gaskets are the real problems. A smaller displacement really gets affected a lot from the loss of static compression and unless you pay to blueprint the block, and pay to buy custom pistons with good valve reliefs but tall enough to still have compression, and pay for a set of thin, small bore head gaskets, the result is it's hard to get decent static ratio. Decent being 9.5-10:1 true compression. That's not to say they won't run, and run well. But it limits other choices like cam, gearing, convertor, etc. They most certainly can be built, and buil to make some great power for a street car. But it takes more than shelf parts and a thin budget. I have a 273 for my '65, but chances are it will get either a 5.2L Magnum or LA 360 dressed like the 273 because I don't have the cash to spend on what I'd call properly building the 273.
 
Youngthrill said:
I plan on rebuilding the 904 and upgrading to a 8 3/4 with 3.91 gears ...any can suggestions? ??not sure if I should go. 30 over or stay stock any input
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Just remember that the 904 for the 273 is not the same for the 318/340/360. I believe that this 904 is known as the '904-A'. Torque Conv & Input Shaft Sizes are the issues (if I recall). Don't make my mistake & get everything in-place...only to find that my good 318 / 904 didn't mate up to my 273. But what can I say, I'm often not too bright.
 
If what you've got is a 273, then use it. The 273 in my '67 B'Cuda is a BEAST, but it was built up pretty good. Some of my specs are fuzzy becasue it's been a while, ironically not many miles, though. Here's what I did:
* .030 Bored out
* Machined a set of 1985 CopCar (actually 5th Ave) heads w/ thicker head gasket (wanted to use cheaper gas, but shoulda gone w/ more compression b/c I can use E85 at times). Would port them if I did it again.
* Headers, Dual Exhaust added
* Road Demon 625cfm CArb (might have gone w/ a Thermoquad today)
* Wieand Stealth Intake
* Larger, oversized cam (forget which one - 2 or 43 steps up from stock...maybe 4 steps...)
* MP Orange Box Elec Ignition
* Rebuilt 904 Trans w/ a higher stall Torque Conv (2400-2600rpm, as I recall)
* 8.75 Rear End w/ 2.76 gear (it was free). I'd love a 3.55, or so.

* Pretty much everything else new or refurb'd

Haven't done any racing or had it dyno'd, but I'd bet it pushes 280-300hp. It's good to hear that the 273 needs some higher revs - I never really have experienced the potential of this engine because I just never really drive it hard. Kind of a shame, I think this engine might be wasted on me!
 
My 273 setup -
4 speed man.
port n polished heads
dual exhaust w/ h-pipe
Lunati Cam .515/.525
Holley double pumper 600cfm
8 3/4 sure grip 4.10 - 26" tire
stock exh. manifold but looking to get headers to work witha 4spd n pwr steering

Never ran her at the track...power band is from 4000 - 6000rpm
Compared to other cars I had it feels like a high 13 sec. car if I ever learn how to launch a stick properly... About 12mpg cruisin' hard
 
Darter6 said:
Several years ago a guy was racing a 68 4 door dart with a 273. It was street driven and was running in the 12's. Do a search for factory ratings on compression and see the difference between the 2bbl and 4bbl engines. If the bores are good, you may want to use the pistons you have.
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If the bores are good, your pistons are about .02 higher compression distance, to make up for the newer open chambered heads. If you get early closed chambered heads or 302 castings then your compression should be good to go.
 
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