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Sppike Mike

Sppike Mike

Why drive what other people like?
Joined
Apr 25, 2010
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Vista, Ca
I've got a 273 with 360 heads and a edlbrock performer 318/360 intake. 1406 600 cfm carb and a really lopy cam ( no idea what the specs are I didn't build the motor). It's in the topless 65 dart in my profile picture. I bought the car and have no back ground info on the engine build other than verifying that the heads are 75 360 heads that have been milled to fit the 273 from the casting numbers. Ive got it running good but it seems to be all bark and no real bite. step on the gas and it makes lots of noise but doesn't really pull. I was thinking it's due to the stock 2 into 1 exhaust. I plan on running fenderwell headers to try and make it breath better. From what I was told the bottom end of the engine is stock. If after I add the headers it doesn't improve enough I was thinking I might build a 318 short block so I can use the 360 milled heads. What pistons are recommended? What years 318 short block do I wanna look for? What else is needed to make the built 318 work with the stock 65 904 tranny? also, can i use the cam outta the 273? And what pistons should I upgrade to to match the cam and intake? There's a 904 tranny behind the motor. Any help would be very appreciated. Thanks
 
For starters,I,d like to know what rearend and gears you have?This could be why she,s all bark and no bite.LOL:rambo:
 
I believe they are the stock peg leg 7.25. Cruises down the freeway good at 75 no problem. no over rev. PettyBluDart :)
 
I'm pretty sure it's the stock 7.25 with factory gears as it cruises down the fwy at 75 no prob and no overrev. :)
 
Other than the gears it seems the engine isn't smartly built and over cammed. personally I would skip the 318 and head straight for the 360...it has a longer stroke than the other two engines. Longer stroke equals more torque,
 
Sounds like a textbook example of a "miss-matched combo". Small port intake, big port heads, really low compression, big cam, small exhaust system, tall gears, low stall converter, etc...

The heads have been "milled to fit the 273"?!? They are a bolt-on. I hope that means they have been milled A LOT to raise compression, like .060-.080. If you didn't have to order custom shorter pushrods, they haven't been milled enough. I am guessing you have about 7:1 compression.

I agree with just installing a 360. Even with the milled heads, you probably won't have too much compression, but 75 heads aren't anything special so look for a 360 with heads on it. A late model 5.9 Magnum truck engine would be a good starting point.

Yes you could use that cam in any LA engine, but not knowing what it is... Plenty of nice rollers out there for the Magnum.

Smash the factory exhaust manifolds with a hammer so you won't be tempted to use them. Cut the single exhaust into tiny pieces for the same reason.

A 360 will bolt to the current transmission. You'll need a counter weighted flex plate. Converter selection is limited for the earlier transmissions. Just how long do you expect a 47 year old low performance transmission to last behind a high performance engine?

The 7 1/4 will break as soon as your engine is capable of generating torque. Are you still running 9" drums ans single circuit master cylinder?
 
Theres no reason you cant make it run better with some tuning. Start with the distributor. Get the timing set correctly, Not just by setting the total timing.

Its probably got low cylinder pressure due to the big heads and cam and no initial timing. Stock timing specs are for emissions not performance.
 
Thank you everyone. I truly appreciate it. I'll run this till I can't stand it then search for a 360 that I can build.
 
I think that you should look into the compression issue. I put 360 heads on a 318 that had 10.5 compression and it brought it down to 9.2. They will bring a 273 down more since it has smaller cylinders. So whaever your compression is with stock heads, it will bring it down about 1.5 in compression if no milling was done.
 
krazykuda said:
I think that you should look into the compression issue. I put 360 heads on a 318 that had 10.5 compression and it brought it down to 9.2. They will bring a 273 down more since it has smaller cylinders. So whaever your compression is with stock heads, it will bring it down about 1.5 in compression if no milling was done.
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Possibly / probably more in this case, as the 273 should have closed chamber heads, and the 360s are open and huge in comparison. If it were mine, I'd get a set of 87-91 318 heads from a junkyard, clean em up, swap the valvesprings for those on your 360 heads, and toss em on. Can't run any worse, and I am certain it will run better, despite the loss of high RPM breathing. If you are on a budget, have stock gears and convertor, and must choose between compression and breathing, ALWAYS choose compression.
 
I think 2 things

1 compression ratio

2 the 2 into one exhaust.

MANY years ago I had a 440 with an unknown "freebie" solid cam, measured at "somewhere" over .5 lift and "around" 300* duration. Thing ran like a bomb an pulled clear up to 7K

I put the engine in a '64 Dodge, and didn't have headers, only the "log" manifolds and dual exhaust.

THAT THING WAS SLOWER than a stock 335 hp 383!!!
 
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