Carb choice for a mutt motor.
Hi crew. I'm a little green when it comes the venerable 318 LA motor.
I tortured a couple of 340 motors in my misguided youth, however a huge volume of water has passed under that bridge.
I recently acquired a 67 Barracuda. Mix-n-match 318 of unknown bloodline. Factory 273 exhaust manifolds w/duals. 4 speed, 8.75 diff w/3.73 Sure-grip.
The known:
Originally 273 273 2bbl.
68 318 block.
? Year 273 heads.
65 cast iron 4bbl intake.
600 CFM Edelbrock carb w/vacuum secondaries.
The unknown: Bore size.
Stock, oversize?
Compression ratio.
Low, I assume.
Cam specs.
Stock, I assume.
In knowing that the 273 2bbl heads are really hindering flow, I feel that the 600CFM carb might be overkill. I understand that the motor will only pull so much air. Only as much as it can process. I just feel that because of the lack of secondary response when under full throttle. I have just cause for questioning whether or not this particular mismatched engine would work better with a smaller (500cfm)
carburetor?
In using the standard formula for CFM configuration, I come up with 440 CFM. I don't spin the motor past 4800 RPM, simply because it seams to have ran it's race by then. When in a lower gear and standing on it from say, 2500 RPM, the result is very
uneventful.
With funding is still in the recovery mode from the purchase, it's not feasible to just slap another carb on it. Not to mention that it seems the price of smaller carbs are grossly overinflated. I have researched the CFM rating of 273 HiPo carbs, but feel like that engine had a more balanced approach with hotter cam, etc.
Just looking to gather some insight from someone who has experienced similar issues. All input is welcomed, just member this. I'm not making any changes anytime soon, although I know the engine would benefit from them. From what I'm learning, a 360 may lay ahead in the distant future. For now, I just want to see if I can get this little mutt to be a better driver. Enjoying the forum. Learning tons.
Hi crew. I'm a little green when it comes the venerable 318 LA motor.
I tortured a couple of 340 motors in my misguided youth, however a huge volume of water has passed under that bridge.
I recently acquired a 67 Barracuda. Mix-n-match 318 of unknown bloodline. Factory 273 exhaust manifolds w/duals. 4 speed, 8.75 diff w/3.73 Sure-grip.
The known:
Originally 273 273 2bbl.
68 318 block.
? Year 273 heads.
65 cast iron 4bbl intake.
600 CFM Edelbrock carb w/vacuum secondaries.
The unknown: Bore size.
Stock, oversize?
Compression ratio.
Low, I assume.
Cam specs.
Stock, I assume.
In knowing that the 273 2bbl heads are really hindering flow, I feel that the 600CFM carb might be overkill. I understand that the motor will only pull so much air. Only as much as it can process. I just feel that because of the lack of secondary response when under full throttle. I have just cause for questioning whether or not this particular mismatched engine would work better with a smaller (500cfm)
carburetor?
In using the standard formula for CFM configuration, I come up with 440 CFM. I don't spin the motor past 4800 RPM, simply because it seams to have ran it's race by then. When in a lower gear and standing on it from say, 2500 RPM, the result is very
uneventful.
With funding is still in the recovery mode from the purchase, it's not feasible to just slap another carb on it. Not to mention that it seems the price of smaller carbs are grossly overinflated. I have researched the CFM rating of 273 HiPo carbs, but feel like that engine had a more balanced approach with hotter cam, etc.
Just looking to gather some insight from someone who has experienced similar issues. All input is welcomed, just member this. I'm not making any changes anytime soon, although I know the engine would benefit from them. From what I'm learning, a 360 may lay ahead in the distant future. For now, I just want to see if I can get this little mutt to be a better driver. Enjoying the forum. Learning tons.