Hypothetical 318 Builds

-
Compression, compression, compression and a good set of heads will make the old teen act like a performance engine.
The last teen I put together I did all I could to kill compression, because I am going to boost it. Poor old gal has 6.97 dynamic compression, but I am adding boost with a 671, 10 psi the engine becomes 11.71 so it may stay together.
 
toolmanmike said:
Looks like may be 400 + horse. It might like a little bigger carb though.
Click to expand...
I would be stoked if it hits 400hp, wasnt particulary trying for a number just a good strong motor. I agree there's a few more HP to be had with a bigger carb - I wanted to try out an AVS2 as many people rave about them, after much deliberation i opted for the 650 over the 800cfm. I wouldn't mind throwing an air gap and a bigger carb on it eventually but I already had the weiand intake hanging around.
 
Ted265 said:
I would be stoked if it hits 400hp, wasnt particulary trying for a number just a good strong motor. I agree there's a few more HP to be had with a bigger carb - I wanted to try out an AVS2 as many people rave about them, after much deliberation i opted for the 650 over the 800cfm. I wouldn't mind throwing an air gap and a bigger carb on it eventually but I already had the weiand intake hanging around.
Click to expand...
Yep, use what you have and make it work. A 300 horse Teen would be fun. 350 horse isn't out of reach for sure.
 
toolmanmike said:
Yep, I purposely left the heavy hitters out. (thinking more fun street engines here) I bet that 375 horse was a nasty Mo Fo. 2.02 double humpers and a big "full race" solid lifter cam. :lol: Then think about the mild combination Hot Rod put together for their 400 horse 318 build. No comparison how easy 400 horse is to get out of a Teen. Better cam technology now days though.
Click to expand...
My favorite was the 365/327 because the mechanical fuel injection on the 375, while super cool was real finicky. And yeah, as long as someone is willing to spend a little dough on some head porting, 400HP is very reachable with a 318. ....and yet, people still piss all over them.
 
RustyRatRod said:
My favorite was the 365/327 because the mechanical fuel injection on the 375, while super cool was real finicky. And yeah, as long as someone is willing to spend a little dough on some head porting, 400HP is very reachable with a 318. ....and yet, people still piss all over them.
Click to expand...
Sad but true!
 
Hypothetical engine needs some hypothetical simulations.... so this is without a detailed cylinder flow table, just a constant number scaled from 340 heads with 2.02 valves. I thought based on cylinder volume and valve diameter that 106 LSA was too tight... ran it with 108 and 110 LSA as well.... you decide what you care about... a bit bigger peak HP number at higher RPM or more lower RPM torque.... can not figure out how to not have for forum downsample the image so it looks blurry

Hypothetical 318.jpeg
 
Jim Kueneman said:
Hypothetical engine needs some hypothetical simulations.... so this is without a detailed cylinder flow table, just a constant number scaled from 340 heads with 2.02 valves. I thought based on cylinder volume and valve diameter that 106 LSA was too tight... ran it with 108 and 110 LSA as well.... you decide what you care about... a bit bigger peak HP number at higher RPM or more lower RPM torque.... can not figure out how to not have for forum downsample the image so it looks blurry

View attachment 1716145675
Click to expand...
Can you size that for blind folk?
 
I'm using a set of PBR's ported Speedmaster's and LD 340.
 
Jim Kueneman said:
Oh and when running this model you MUST, MUST have headers to crest the 300 HP line or you may not make it. Stock 340 manifolds capped you at about 290 HP
Click to expand...
Sounds about right. You just cannot preach headers to some folks though. They won't have any of it.
 
fishmens67 said:
A solid in the 250-260 @ .050 570 -580 lift range.
Click to expand...


Did you do a lot of work to the heads (or aluminum?).... with stock'ish heads that will be too much cam and won't be able to use what it is trying to give. it will destroy lower end torque in the process... theoretically...

 
RustyRatRod said:
Sounds about right. You just cannot preach headers to some folks though. They won't have any of it.
Click to expand...

I will not use them but I am not trying to get peak anything... just a nice running cruiser with a bit more punch than stock.
 
Jim Kueneman said:
Did you do a lot of work to the heads (or aluminum?).... with stock'ish heads that will be too much cam and won't be able to use what it is trying to give. it will destroy lower end torque in the process... theoretically...

Click to expand...

Hypothetically I'll be using PBR's worked over Speedmaster and matched LD 340 intake
 
Jim Kueneman said:
I will not use them but I am not trying to get peak anything... just a nice running cruiser with a bit more punch than stock.
Click to expand...
Nothin wrong with that. I don't have um on Vixen yet. Yet. lol
 
@fishmans67 318 with a 255/255 0.375 lift, 11:1 (important to note that cam duration and compression ratio must be matched... this cam with 9:1 would suck), single plane intake, headers, 2.02"/1.7" valve with the assumption that the head can flow way more than a stock head.... vs @RustyRatRod's street build. This is a great comparison to showcase what you lose to gain high RPM HP numbers. What is important is up to you in the build. You rarely get something for free.... for me I want under 4000 RPM torque so I always choose lower compression and a shorter duration cam (to keep the cranking pressure under 200 PSI) to maximize the torque curve in that area. Rusty wants to wind it up a little so he has a bit higher compression and a bit longer duration cam where @fishmens67 is after all out high RPM horsepower and willing to compensate for the loss of torque at lower RPM with lower gears. I cruise for hours at 80 MPH so super low gears are not an option for what I want out of my builds. I hope this is informative for someone in their builds... it is all a compromise. These days to it's not difficult to get a first order prediction of where you are with simulation tools. The magic is the second order secret tweaks to get that slight advantage where you want it.

 
Last edited:
Jim Kueneman said:
Where in earth did you find those pistons? It drove me crazy to have to use. Low compression pistons on my 68.
Click to expand...

Yep, have a set of the 9.2:1 factory pistons here along with the matching light full floating rods.

Sweet setup.....

☆☆☆☆☆
 
George Jets said:
Yep, have a set of the 9.2:1 factory pistons here along with the matching light full floating rods.

Sweet setup.....

☆☆☆☆☆
Click to expand...

Fun to argue with people that 318s were always low compression dogs. First couple of years they were not. Only when the 340 came out and they needed to widen the gap between the performance of the new 340 and the 318 for the marketing to sell the new 340 did the compression tank.
 
Last edited:
You must log in or register to reply here.
-

Back
Top