318 Factory Four BBL Intake Manifold

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Factory 318 4bbl, yes. I have 2 trucks with.
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318 4bbl truck engine with dual snorkel air cleaner. Gotta love it! 65'
 
krazykuda said:
I meant LA 318's....

I just didn't state that in my reply as you had already posted that poly's had 4 bbls and I was implying LA style in my post.

Yes, poly's did come with 318's but I'm not aware of any LA 318's coming with 4 bbl from the factory... Maybe a truck in the 80's possibly, but I'm not aware of it... Or a cop car...
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I’m not sure when 4bbl’s made the 318. It’s not a thing for me to remember. It’s kind of in the back draw down low in the storage center of the brain behind the crusty rusted locked door in possibly the left hand corner. Who knows?!?! LOL!

It’s all good. I modify most everything anyway. I have not come across a car that 1: I want to restore properly & 2: Actually worth restoring. I mostly buy junk and have fun with it.
 
rumblefish360 said:
I’m not sure when 4bbl’s made the 318. It’s not a thing for me to remember. It’s kind of in the back draw down low in the storage center of the brain behind the crusty rusted locked door in possibly the left hand corner. Who knows?!?! LOL!

It’s all good. I modify most everything anyway. I have not come across a car that 1: I want to restore properly & 2: Actually worth restoring. I mostly buy junk and have fun with it.
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I consider my mind like a computer hard drive...

When the memory gets too full, I have to delete some old files to make room for some new ones....
 
318willrun said:
360 intake on 360 heads from my experience.
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What kind of compression were they running with the larger combustion chambers on the 360 heads???

Did they adjust the pistons to compensate or keep the same old standard pistons and take the hit on compression???
 
krazykuda said:
What kind of compression were they running with the larger combustion chambers on the 360 heads???

Did they adjust the pistons to compensate or keep the same old standard pistons and take the hit on compression???
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Not as much of a compression loss as one would suppose. When a guy has to choose between slightly lower compression with more flow, or the reverse, flow always wins. It's why I've stated here many times that I've NEVER put 360 heads on a 318 and lost power. I can tell you from the experience of driving them, the factory 318 Thermoquad (when up to snuff) will kick the living gizzard out of a 318 2bbl.
 
318willrun said:
Not as much of a compression loss as one would suppose. When a guy has to choose between slightly lower compression with more flow, or the reverse, flow always wins. It's why I've stated here many times that I've NEVER put 360 heads on a 318 and lost power. I can tell you from the experience of driving them, the factory 318 Thermoquad (when up to snuff) will kick the living gizzard out of a 318 2bbl.
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The loss from the drop in compression is only about 3 - 5 HP according to the desktop dyno when you run it with just the compression decrease....

But you get more power from the increased port flow...
 
I’m not sure of the exact numbers but it wasn’t a lot of gain especially running it through a single cat.
 
318willrun said:
Not as much of a compression loss as one would suppose. When a guy has to choose between slightly lower compression with more flow, or the reverse, flow always wins. It's why I've stated here many times that I've NEVER put 360 heads on a 318 and lost power. I can tell you from the experience of driving them, the factory 318 Thermoquad (when up to snuff) will kick the living gizzard out of a 318 2bbl.
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krazykuda said:
The loss from the drop in compression is only about 3 - 5 HP according to the desktop dyno when you run it with just the compression decrease....

But you get more power from the increased port flow...
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The hit you take with the compression drop is in the efficiency...

Here is a Yale professor deriving the otto cycle efficiency to prove it... Open your books to page 218 and follow along...




Or skip to the end here:

 
krazykuda said:
The loss from the drop in compression is only about 3 - 5 HP according to the desktop dyno when you run it with just the compression decrease....

But you get more power from the increased port flow...
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Funny, my neighbor had a later 70's 15 passenger Maxi van that he carpooled back in the day. It had a 318 TQ from the factory. He outran a '57 chevy with a 350 4bbl with it, he could outrun the 360 TQ's in other vans that carpooled to the same place, and he could lay black marks with it at will. It caught on fire with 246,*** miles on it ending it's journeys.
 
I've owned a couple of ex-police cars with 318 4bbl's. I still have a speedometer for a diplomat that goes to 125 mph. I wish I had my channel back in those day (no youtube existed lol).... man, the content and crazy "will it run" episodes we did off the camera. LOL. I was Roadkill before the West Coast guys ever gave it a name. :)
 
318willrun said:
Not as much of a compression loss as one would suppose. When a guy has to choose between slightly lower compression with more flow, or the reverse, flow always wins. It's why I've stated here many times that I've NEVER put 360 heads on a 318 and lost power. I can tell you from the experience of driving them, the factory 318 Thermoquad (when up to snuff) will kick the living gizzard out of a 318 2bbl.
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I agree. BTDT
Bodyperson said:
I’m not sure of the exact numbers but it wasn’t a lot of gain especially running it through a single cat.
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That was the problem. A dual exhaust even w/cats would have been a nice improvement.
318willrun said:
I was Roadkill before the West Coast guys ever gave it a name. :)
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Oh! If you tube only existed then. The crazy video I could have put up!
krazykuda said:
The loss from the drop in compression is only about 3 - 5 HP according to the desktop dyno when you run it with just the compression decrease....

But you get more power from the increased port flow...
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Yes, but, I think you’ll see a good bit more low end torque on the program?
 
the 318 cop cars used the 360 heads as stated above used q-jet carbs. this is the chrysler part number for the 86 intake. 4323354. not sure of casting number though.
 
318willrun said:
318's came with 4bbl's in the later 70's up into the 80's. Maxi Vans, Pickups, Ramchargers, Police Cars, and some passenger cars all were optioned with the 4bbl.
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This and seen quite a few at the You Pull It
 
This discussion brings a question to mind. Regarding the small port 318 head vs large port 360 head. Basically, flow vs velocity in small cubic inch engines. My understanding is that higher velocity will give more low end torque than high flow. Please educate me. Thx 65'
 
318willrun said:
Pretty impressive how hard the factory 318's with TQ engines would run.
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Really?Your experience is different than mine. The early 80's 318 trucks I experienced were horrible running piles. My grandad did probably half a dozen swaps to the the 360 2v intake and carbs on these for people. I remember one guy in particular raving how much better his truck ran. Thats actually how I got my first la 4v intake. It was one he swapped for my school bus driver.
He used to swap on a little holley economaster 4v carb for people also. That was an improvement also.
 
The 318 never had its own specific 4 barrel intake. Chrysler used the 360 intake on the 80s model 318 police cars. They used both the Thermoquad and the Quadrajet.
 
HankRearden said:
Really?Your experience is different than mine. The early 80's 318 trucks I experienced were horrible running piles. My grandad did probably half a dozen swaps to the the 360 2v intake and carbs on these for people. I remember one guy in particular raving how much better his truck ran. Thats actually how I got my first la 4v intake. It was one he swapped for my school bus driver.
He used to swap on a little holley economaster 4v carb for people also. That was an improvement also.
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Brings to mind, one time I test drove a 2 door Aspen that had a factory 318 4bbl. I don't know if it was a Chief car or what, but honestly, I was completely shocked how quick the car was. I had a '77 Aspen R/T with a 318 2bbl, and the difference made mine feel like a slant six. I've driven a ton of factory 318's, but I don't think none quicker than the one I mentioned.
 
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