Technical LA 318 and getting proper quench, possible?

And Mike @Budget36
If this horsepower / torque specs above is correct it indicates the engine is "starved" of air.
Maximum torque is usually the highest rpm at maximum cylinder fill [volumetric efficiency]
Beyond that the cylinder fill diminishes but the rpm increases which shows as a flat horsepower curve.

If maximum torque is 320 ft/lbs @ 2000 rpm this is only flowing 184 cfm of air
At 4400 rpm it is only 274 ft/lbs torque [85% of maximum torque] which is flowing 344cfm instead of 404 cfm at 100%

A 4 barrel intake and 500 cfm vac secondary carb would get you there.
I would also consider doing a good 3 angle valve job on the intakes so they flow better "off the seat"
A valve job doesn't hurt driveability only longevity [7 years instead of 10]

If you choose a cam........... go for a "stump puller"
And headers don't hurt

 

I’m now formulating a plan using the pistons I have in it, decking the block for a true 8.2-8.5, and have the intake milled properly as well.
I have two small Holly’s, one spread bore, one square bore. Both vacuum secondary. I’d have to recheck which is which and the CFMs, but both 600 and less

 

I think you’ll hit target power easily and I think you’ll get good economy also with what you have, you could improve upon what you have but would it be worth the $$$s and time?
Dan

 

Are the newer motors equipped with a roller cam ?
That would be very nice. Possible to retrofit ?

 

The top end is different. Not really mix 'n match there. We are talking from the cam up, lifter bores, pushrods, heads.
There are lots of discussions on it. I haven't watched this guy, but here's an example.
www.youtube.com/watch?v=ZxHmKv-4zGY

 

The later model Magnums are a better engine a lot guys convert to carburetors and they have roller cams. That was my original plan but I found a good running 318 in a car so I have alternator, radiator, transmission linkage etc. for less money than just an engine.
I think Budget 36’s set up will do what he wants pretty much as is.
Dan

 

Well, here’s the first pass at it. I’d number them, but it would be like a Chevy…
D-side front .095
D-side rear .100
P-side front .105
P-side rear .095


Now the above was all based off the driver side deck. I figured keep one reference point.

edit: driver side is the left side sitting in a vehicle.

 

Is that with or without the gasket ?

Pic of the chambers ?

 

No gasket. Straight on the deck, magnetic base and dial indicator, it tells me enough, HF stuff, “accurate to .001” yes, okay

I can post a pic of the chambers later, but they are open chambers, there is a small pad in them, maybe a 1/4 inch from the head decks.

 

What was Chrysler thinking ?

 

lol. Here’s the CC pic.

Will need some cleaning, had the intake sealed off, but never did the exhaust manifolds, , left them like the pipes were going on tomorrow. “Thule Fog surface rust”
At first glance what appeared to be a surface, was the difference from chamber to plug hole. Easily seen now.

 

Can they be milled enough to fix this problem ?

 

Naw, after I get the deck where I want it, will be maybe .080- .070 piston to deck, but much better squareness that the factory had.
Maybe 8.25-8.3:1 SCR, and a true engine rated factory HP, maybe the slightly more compression, .030 adds 5 HP to Mopar’s numbers, I’m good with that. Truck weighs 2525lbs. Well, data plate on the dash says so, with the flat 6 in it, maybe add a 100? For the 727 I have vs the 3 speed manual, just a guess.

 

More like the machinists working for Chrysler.
Just throw the block on the bed and take one pass with the mill.

Absolutely!!!
They are approx 0.015" and 0.025" taller than the standard 9.60" deck height.
I've never seen a L.A Block that was lower than stock


Me being the "King of Cheap" would install a set of KB399's in it and call it a day.
Or if it was decked square to the LF and RR heights install a set of KB167's [9.06:1 with 0.039" Fel--pros]

Taking 5 thou off 1 corner and 10 thou off another wouldn't affect the intake manifold matching

 

That’s a real good point Kerry, just leave it, and change pistons. Cost would be comparable, little more than the decking, but nut 10$ vs 200$, etc.

Plus, easier to haul pistons and rods in for a swap, than a block!

I know you musta told me that twice, guess the third time a charm!!

 

Those chambers are horrible.

 

They will look a bit nicer, but won’t hold a candle to AFRs

 

With drop-in KB399's you would end up with 9.69:1 compression on the lowest deck and 9.47:1 compression on the tallest deck
0.22:1 is a moot point on a less than 250-300hp engine

On summits website the KB399's are only $42 more than KB167's [both have the same compression height]
I doubt if you could deck the block for $42

Plus you haven't dicked with the block [for future projects]
-------------------------------------------------------------------------------------------------------------------------
But if you're are really cheap [I am] just refresh it , and don't bother with decking or changing pistons.
The engine has already survived 50+ years so far.
A cheap hydraulic cam/ timing set [cheaper than pistons] Valve Job, and 4 barrel will get it over the line ..... [230 hp]


This Cheap Summit cam fits the bill nicely
https://www.summitracing.com/parts/sum-k6900/make/chrysler

Duration at 050 inch Lift: 204 int./214 exh.
Valve Lift with Factory Rocker Arm Ratio: 0.421 int./0.444 exh.

 

As usual, money. A low precision design can use low precision parts and low precision assembly, making parts with low precision on some areas and/or not checking measurements on assembly saves time and money.

 

With the deck, I just assumed worn tooling and no verification. I recall after some years of Chevy making the 265’s, talk of poorly machined blocks, due to the tooling being worn out or not serviced properly, etc.

No reason Mopar would not use the same tooling and adapt when needed.

 

Decks not being square, end to end is one thing.
Pistons .100"(plus the gasket) down the hole, with that crappy chamber, is just dumb.

Clearly they not read
The High-Speed Internal-Combustion Engine
by Sir Harry Ricardo.

 

Chrysler never intended for the 318 to be a performance engine, they installed them in everything from econoboxes to land yachts and trucks. Most of them just run and run. In stock form they make 140 to 150 HP net, with a few run of the mill simple bolt on parts a 4 bbl, cam , headers, and recurving the distributor will get you 225 to 275 HP without any unneeded machine work or parts. A very low dollar build.
They can make 400+ HP but require machine work, pistons, heads etc. a fairly high dollar build. Just my 2 cents.
Dan

 

Its interesting that you want to compare Chrysler's bread and butter utility motor to your hypothetical dream motor and complain about things like quench, combustion chambers, and how far down in the hole the piston sits.

How about you pull down the lowly 307 Chevy or the run of the mill 350 2 bbl and see what those numbers look like, or the old non-hippo 302 or 351 W with factory 2bbl carb Fords to compare the numbers?

 

Come on Gene, now you're trying to put logic in the equation....

 

@Budget36 i believe you are looking for a 4 bbl manifold for your 318. I found a couple on For A bodies only for fair prices
https://www.forabodiesonly.com/mopa...nes-casting-2531915-2-date-code-10248.573591/
A factory 340 manifold
And an aluminum Elderbrock
https://www.forabodiesonly.com/mopar/threads/edlebrock-streetmaster-318-intake-manifold.573963/
I have the Holley street dominator similar to the street master. These are good mild build manifolds that produce power from lower RPM up. I think the prices on either manifold is very fair.
Dan

 

Heck, been in and out of that site multiple times, never thought to look for the classifieds!
Thanks

 

I have a factory 340 intake on the 360 in my Fargo and a street master 318 on the 318 in my barracuda, both work well for my application. I wouldn’t run the street master on a serious 318 build

I should add the street master is a single plane small runner intake, will not flow bunch at high rpm.

 

A little off topic, since you have engine partially apart a windage tray is worth 2 to 10 HP mostly above 3000 or 4000 rpm. For $80 I think it’s worth it.
If you install new pistons you might be able to sell your your old pistons.
Dan

 

Good bunch of guys there, I’ve bought a few things off the classifieds, never a problem

 

I’m send the $$ for the StreetMaster today. Thanks @Sharpone !