Are we up to the 6th thread on him building an engine?
318 For Fun
- Thread starter Dan the man
- Start date
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I think so! And for what he's talking about building, a 360 with 318 heads may be what he really wants but doesn't realize it yet. We put a 1974 industrial 360 into a club cab truck a few years ago that had a set of small port 857 industrial heads with exhaust crossover. It had a 340/360 four barrel cam, headers, Edelbrock Performer and 650 AVS2. It would freight train off idle until it hit 4500 rpm, at which point it went strait into turdville, quit accelerating, and just made a bunch of extra noise. But it would blow the tires off at will below 4500 rpm, though.
Few more things
1st I assume most people aren’t gonna port or have their heads ported especially to get the best power and velocity for the application. At best maybe a little bowl cleanup and gasket match.
2nd the 318 head was designed for a 273 size engine it has decent flow for a
273 cfm to cid ratio is about the same as a 340, right cam and cr 300 hp possible. The 318 is 45 cid bigger than the 273 and only 22 smaller than a 340 less once over bore.
problem with 318 is cr and head flow
With factory long block 4bbl headers and xe262h cam has dyno 282hp @ 5000 rpm not too bad easy to do. Above that you could squeeze 300 hp with more cam but really should be considering better heads. With the cost of Speedmaster it hard to justify putting money into factory heads.
Speedmaster intake and heads 650/750 carb headers decent cr which leaves cam, put a pretty mild cam like xe250h for easily into the 300 hp very streetable setup to xe285hl and more cr for 400 + hp for street strip car and anything in between.
1st I assume most people aren’t gonna port or have their heads ported especially to get the best power and velocity for the application. At best maybe a little bowl cleanup and gasket match.
2nd the 318 head was designed for a 273 size engine it has decent flow for a
273 cfm to cid ratio is about the same as a 340, right cam and cr 300 hp possible. The 318 is 45 cid bigger than the 273 and only 22 smaller than a 340 less once over bore.
problem with 318 is cr and head flow
With factory long block 4bbl headers and xe262h cam has dyno 282hp @ 5000 rpm not too bad easy to do. Above that you could squeeze 300 hp with more cam but really should be considering better heads. With the cost of Speedmaster it hard to justify putting money into factory heads.
Speedmaster intake and heads 650/750 carb headers decent cr which leaves cam, put a pretty mild cam like xe250h for easily into the 300 hp very streetable setup to xe285hl and more cr for 400 + hp for street strip car and anything in between.
Dan the man
Well-Known Member
Are you directing this comment to me?
Dan the man
Well-Known Member
I noticed a "eye" on my latest 3 post, what's that mean?
Just find a good set of factory heads, check them out, & get a valve job done. This is not going to be some high HP monster. Something you can do yourself with an elec drill & carbide burr or stone is remove any sharp edges under the valve seats in the heads. Perf intake & 600 Edel carb. Since you have headers, the last thing you want is a dual pattern cam because it will take way from the low end which you are trying to improve.[ See Isky Cams Tech Tips on exh duration ]. Use a cam with 108-110LSA, such as Comp 252 Hi Energy or Isky 256 Supercam.
I don’t know. Ya got me bro!
This is true, Ive run 1.88 J heads on a 273, It was not torque challenged. It is all in the combination.
PRH
Well-Known Member
It always is.
And I’m betting that’s been mentioned numerous times in the various recent “how to build a 318” threads.
Dartswinger70
Well-Known Member
I wouldn't take it personal, its just another version of this:
Because of all the "build a 318 " threads that I personally blame Uncle Tony for. he started the "318 can do what a 340 can do bullshit" well the bullshit is, it cannot be done cheap and he pushes on the cheap all the time.
Dartswinger70
Well-Known Member
In summary I say, run the LA 318 in its basically stock configuration, this is where the engine really shines. 235 HP 340 FP torque at 2400 RPM according to allpar.
Just make sure its in a good state of tune and running properly. Why do any more than that ? ( if on a budget) if you really want to play around, degree the cam, do some carb work , distributor work, etc. that falls under "good state of tune" category.
Just make sure its in a good state of tune and running properly. Why do any more than that ? ( if on a budget) if you really want to play around, degree the cam, do some carb work , distributor work, etc. that falls under "good state of tune" category.
Corrected.
Along those lines, with 230 horse with a stock cam, 2 barrel, and manifolds, building a 300 horse engine shouldn't be a big deal. You can build a 400 horse engine fairly easily as well. If you want. Or you can find a 360 or a Magnum and get there easier and probably cheaper.
Dartswinger70
Well-Known Member
well lets just say you start with the LA 318 2 barrel stock cam than add headers and duals How much horsepower is freed up with headers and duals?
then from there a 4 barrel say a 600 cfm or smaller...
after that a cam, a carefully chosen cam one that works with the low compression flattops in the LA 318
Then rear gears ...and I'd stop there before going into the engine, as in a over bore and high comp pistons and bearings starts to cross the budget line for me Id go with the 360 or 5.9 magnum. i think when going after the stock LA bottom end, changing it to bring up compression etc. then one should consider the bigger engine. It just makes economic sense IMO. Keep in mind 230 HP is fun on the street the late 80s Fox bodies were rated at 225 HP. The A body isn't much heavier if it is heavier at all than a Fox Body I seem to think they weigh in around 3000 lbs. So, in reality it isn't like you cant have street fun with a 318 in an A body.
then from there a 4 barrel say a 600 cfm or smaller...
after that a cam, a carefully chosen cam one that works with the low compression flattops in the LA 318
Then rear gears ...and I'd stop there before going into the engine, as in a over bore and high comp pistons and bearings starts to cross the budget line for me Id go with the 360 or 5.9 magnum. i think when going after the stock LA bottom end, changing it to bring up compression etc. then one should consider the bigger engine. It just makes economic sense IMO. Keep in mind 230 HP is fun on the street the late 80s Fox bodies were rated at 225 HP. The A body isn't much heavier if it is heavier at all than a Fox Body I seem to think they weigh in around 3000 lbs. So, in reality it isn't like you cant have street fun with a 318 in an A body.
It would be fun to find out. Engine dyno would work except for the dual exhaust comparison. You could dyno with manifolds then headers for comparison but you wouldn't get the restriction from the single to dual exhaust. All the rest of the changes could come from the engine dyno. A chassis dyno would be better for that and you could note power increases from all the modifications. You would have to calculate drivetrain power losses if you want just engine power specs. You can also spend some time at the track after all the different mods and compare times. Not the very most accurate because of all the differences in traction, temp, baro. pressure and the like. Where a engine dyno is a bit more consistent as far as environment goes) ET and MPH would have to be calculated to horsepower if that's the numbers you are looking for. It's all a guess but the more information you have the closer that guess is. Sorry for the ramble.
Dartswinger70
Well-Known Member
I agree, I wish someone would do it LOL! document their "318 power making adventure" I already stated how far I'd go, but I'm sure someone crazier than I would do the block mods, the overbore with high comp pistons etc. I would be interested to see what degreeing the cam would do in a stock LA 318 that's low buck, save for the cost of the degreeing equipment and timing set.
I think you're spot on with the progression. I would have to back up on my Swinger. The prev. owner split the single exhaust and made it into duals. I still have the 2 barrel and stock 70-318 under the hood. The closest chassis dyno I know of is a hour and a half away but the local drag strip is only 20 min. May be I should take the ol' girl out for some baseline runs. A performance increase would give me a percentage that could get close to a horsepower number.
I have a LD4B and a 650 AVS-2 to go on and I also have some 68 340 exhaust manifolds to go on as well. I need to replace my rusty original/modified exhaust so that could be a comparison as well.
dICKj
Well-Known Member
Before you tear into that engine, or worse, swap it, change to 3.55s. You will be amazed how much more fun you will have!
Yep, like said, the right gears, 4 speed or right convertor, makes a decent running SB fun especially in a light car.
Mom said, Son, you are over thinking it."
Then Dad said, " WTF were you thinking!?"
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