Why are 318's low HP and torque?

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I looked on sumittracing and it seems that there are many different edelbrock performer intake manifolds...for example there's an air gap manifold and then there's a Performer rpm manifold all of which say performer in their titles. Couldn't find the ld4b manifold got a link for that one?
 
The LD4B is an older manifold designed for 273/318 there version LD340 intake, performer has an inbetween port size compromised to work on 340/360 and 273/318 heads. Performer Rpm comes in air gap and non air gap but is designed for 340/360 ports only but under 400HP not needed. So if you can find an used LD4B grab it or get a standard performer.
 
Cool thanks. I will look into the standard performer intake manifolds....would a specific camshaft go well in a stock 318 with that specific manifold? I know that normally cams and intakes are paired in their original designs....?
 
Anything under 268 degrees of advertised duration in your motor would work well.
 
Good thing is 318 cams are pretty wimpy 240ish degree with .400 lift even the smallest performance cam gonna make a big difference but since your engine has low compression you don't want to go to large something under 265 degrees I got a comp cam Xe262H on stock long block with a Eddy performer intake and 600 carb with headers and duals on my 85 5th Ave untill I below my rear end in the magazine write up I got the idea from it made 282HP @ 5000 RPM's.
 
Chryslerkid said:
Since I have been told several times now that my street master intake manifold is crap....what are some good intake manifolds that I could use in place of it?
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So are these manifolds Rubbish? Or what? I have atop an engine in my longest term project that I've not qute got on the road yet.
 
I think I mentioned this, but it's worth repeating. The stock compression height on a 318 is 1.720. You can get aftermarket stock replacement pistons with a taller compression height. 1.741 is a popular replacement. Might not seem like much, but every bit helps. It helps more than you might guess. Those pistons can be had for under a hundred bucks if you shop around.
 
kinda strange though, the way the 360 got the cast crank and the 318 forged, huh?
 
I don't think the 318 got a forged crank but just a few years. I don't really worry about all that since a good balanced cast one will take 550 plus HP.
 
If I take the heads off and have a machine shop work on them what should I do? Port?
 
I don't think I'd worry about that. What are you wanting outta this thing?
 
Man I don't know. I want to be able to drive it and have some power to do burnouts and a little hot roddin' around town. I want it to sound real good. Not really sure how much HP and TQ I need to get the job done....?!
 
250 HP will produce lots of tire smoke and you don't need expensive porting to get there. You can get 300-325 HP with a non ported head on a 318 with good parts choices.
 
Sweet. More bang for my buck! I'm trying to decide what gears an rear end belong in the car with a 318? I have the stock 7 1/4 right now.
 
Chryslerkid said:
Sweet. More bang for my buck! I'm trying to decide what gears an rear end belong in the car with a 318? I have the stock 7 1/4 right now.
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Keep an eye out for an 8.25 or 8.75 rear that's close enough to pick up. It may take a while to find but That's what I'm doing. Either as part of a parts car or separate. I look a few times a week and when I find it I'm gonna pounce. The gear choice is going to be your choice based on how you want to drive. 1/4 mile at at a time? or 50 miles at at time? Somewhere in the middle is always good that way you get some fuel economy but still fun to drive.
 
What can I expect to pay for an 8 1/4 rear end complete from another a body car?
 
StrokerScamp said:
The 318 was the grocery getter, the truck motor, the people mover. It was never meant for high performance use. Even the "police interceptor" 318s were not true high performance engines. They had 360 heads with larger valves and ports to gain flow, but lacked compression. I think Chrysler didn't try to pump it up in part in the late 60s and early 70s, because it could have come really close to the 340 and the 340 WAS Chrysler's performance engine.
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StrokerScamp: You got it! End of story.
 
im working on a 318 too. i got the factory heads should i have them worked over or go to the pick n pull and look for 340 or 360 heads?
 
roylira said:
im working on a 318 too. i got the factory heads should i have them worked over or go to the pick n pull and look for 340 or 360 heads?
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Use the 318 heads. The 340 or 360 heads will kill hell outta compression.
 
Chryslerkid said:
Sweet. More bang for my buck! I'm trying to decide what gears an rear end belong in the car with a 318? I have the stock 7 1/4 right now.
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A 3.55 would be good....but you will sacrifice some high speed interstate driving......or mileage if drive fast anyway. lol
 
My 1965 has a stroked 273 CI using a kit from Eagle. The 4340 forged crank has a 4" stroke like a 360 CI. With a .030 overbore this is 331 CI. With a good solid-lifter cam, some head-work, pistons at about 10:1 compression, single plane intake & four barrel this combo makes over 400 HP easy. I am even using the original cast iron exhaust manifolds extrude-honed becuase I didn't want headers on it. You can do the same thing with a 318 and get 390 CI.
 
I don't doubt it one bit. Sounds like a nice combo. If you ever have the chance to get it on a chassis dyno, I would love to see the numbers.

dynodonn said:
My 1965 has a stroked 273 CI using a kit from Eagle. The 4340 forged crank has a 4" stroke like a 360 CI. With a .030 overbore this is 331 CI. With a good solid-lifter cam, some head-work, pistons at about 10:1 compression, single plane intake & four barrel this combo makes over 400 HP easy. I am even using the original cast iron exhaust manifolds extrude-honed becuase I didn't want headers on it. You can do the same thing with a 318 and get 390 CI.
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StrokerScamp said:
250 HP will produce lots of tire smoke and you don't need expensive porting to get there. You can get 300-325 HP with a non ported head on a 318 with good parts choices.
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Yup.

Here's what I did to mine. Comp HE268H cam, 1 5/8" headers, Weiand 8007 intake, opened up the port entrance on the heads to match the intake (gasket match) and a Summit 600cfm carb. I also run a 3.55 suregrip 8 3/4 rear.

It runs well for what it is and will get me by until I get my new engine built.
 
sheeot. That's kinda close to what I'm doin with my truck motor and I'm gonna leave it in there. lol

Badsport said:
Yup.

Here's what I did to mine. Comp HE268H cam, 1 5/8" headers, Weiand 8007 intake, opened up the port entrance on the heads to match the intake (gasket match) and a Summit 600cfm carb. I also run a 3.55 suregrip 8 3/4 rear.

It runs well for what it is and will get me by until I get my new engine built.
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Very cool! So I guess I don't need much head work if any. I am definitely going to put in a new camshaft, but haven't decided on one yet. I know I shouldn't get a cam with too big of a lift because the stock low compression 318 won't like it. I am hoping to find a nice 8 3/4 or 8 1/4 rear end soon. Other than that, I think I'm going to be happy with my build once it's all done! Thanks y'all! Hey you guys got pics of your engine setups? Thanks...
 
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