AJ/FormS
68 Formua-S fastback clone 367/A833/GVod/3.55s
- Joined
- Jan 19, 2014
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WHYWell my fabo followers ............ My 273 blew up , it cam up with a rod know the other day and I have it all ripped apart already. noise was coming for #5 rod 'spun bearing ", but once I tore into the engine, every bearing was scored and more bearings were spun so bad they looked like tin foil. probally revved too high at rpm 6400 or oiling issues , oil light never came on and it does work , so it had oil , could be alot of things . It's all water under the bridge at this point in time. I have another good 273 crank, rods 10/10 and pistons read to go to the machine shop for clean up and start assembly.
You already know it's not enough engine for you, and probably never can be.
You'll have to punch it up to 1.165 hp/cid.... just to match a 318 at 1.0hp/cid, or a 360 at .88hp/cid
And when you do that.........the bottom end gets a little soft.........again.
If you want to keep the 3.55s....... get a bigger engine; you'll be so much happier.
I've got 273doorstops and 318doorstops and 340doorstops stacked up in the shed double high and 15ft long. Do yourself a favor and drop a stock 360 in there. With headers and a 4bbl, it will kill those 3.55s, and it will barely be working hard.
Oh and get a rev-limiter, some 340 springs, and try and stay out of the 6000s unless you do the required oiling mods, to make it live there.
Once a 360 is in there, then you can justify other mods, that will reap proportionally more benefits in the bigger engine.
Think of it this way; that 286 cam, the way it was handicapped in the 273, was probably acting like a cam that is only 2 or at the absolute most, 3 sizes bigger than the 252FTH that is in a stock 360........but the 360 has a cubic inch advantage that is acting like a cam that is easily 4 or perhaps 5 times bigger at the power peak...in a 273 ....... without the low-rpm penalty.
Here's another way to look at it
to equal a 360 at take off with 3.55s......... the 273 will need about 4.68s; all other things being equal, say at same hp/cid
And another
Say you built them both up to 300hp, and still with 3.55s and same trans, the 273 will need vastly more gear just to keep up with the 360. So on the race track, they might finish pretty close together. But you are not on the racetrack. A streeter needs a strong bottom end. and a 300hp 360 will have, or can have, and should have, a vastly stronger bottom end. In fact, it is easily possible to have waaay more bottom-end than the lite-A chassis can handle, with a 300hp 360
So with that said,even a modest 318 will kill 3.55s without the total waste of power that the 360 brings to a lite-A streeter.
The one advantage to a 300/360 would be that you could run 3.23s or 2.94s and gain some mpgs and hiway comfort.
This is especially true if you have the 3.09 low in that 4-speed box.
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