Making power out of the 318

[carmart1975]

He's 15. I don't know if he knows what it's like to have a "400hp" anything... especially being he isn't even legal driving age yet... Having not yet experienced much "drive time" I'm betting he'd be happy with 275-300 hp. Numbers sure sound good but he can't really know...

No i know what 500hp is like, i drive my dad’s truck from time to time

 

[carmart1975]

Don't have to do everything on day one.
If doing a rebuild do the best short block you can afford that's built around future plans.
Like a zero decked short block, if the top end is a little miss matched, it's ok it's only temporary, down the buy a set of good aftermarket heads etc.. as you go and can afford it. Or find a decent usable short block and spend money on top end.

I really like your thinking i think i will use what i have and use some kind of KB piston but i am a little lost on that should i use 399s or 167s if you dont know thats ok i will dig deeper into the internet

 

[carmart1975]

He also asked to make 425 to 500 hp on a 3k budget now 400 hp on a 3k budget with 3.21 gears and a 318. He also asked what we would do to make 400 hp with 3k, I'm for 318 builds but sometimes people are asking the engine to be too many things. I've made suggestions on many different ways to try to accomplish his goals and 360 only being one of them, if he doesn't want to go that way fine like one of my signatures says "If your willing to gear it build it if not build a larger displacement, Or take solace in your compromises." People just don't seem to get how important gears are to smaller displacements not as important than a good stall but up there.

You are correct i will be getting new gears when i shred the 8 1/4 then will up grade

 

[273]

Ok thank you, by chance do you know of a good cam that i could use with a nice lope i really want a bang for you buck cam if that is possible

Problem is I think you should run less than a 220 degree cam (maybe 225 at most) , but that's at odd's with you wanting 400+ hp and lumpy, maybe a small thumper type cam give you the sound.

1st you got to figure out the head situation, you don't have 400+ hp heads with reasonable cam and cr.

 

[273]

I really like your thinking i think i will use what i have and use some kind of KB piston but i am a little lost on that should i use 399s or 167s if you dont know thats ok i will dig deeper into the internet

1s figure out heads

2nd cam

3rd compression ratio (piston gasket milling etc..)

 

[273]

You are correct i will be getting new gears when i shred the 8 1/4 then will up grade

If you plan on gears down the road and 3.21 are temporary could run more cam and live with the compromise or or swap in new bigger cam when doing rear end swap.

What gears be willing to run with the 8 3/4?

 

[carmart1975]

First thing is to figure out what you have, casting numbers, how much is the block bored now and where will it clean up. What head castings do you have, find the numbers. What condition are the parts? Can you get just one piston? Before you spend any money, magneflux the heads you want to run and find what is the smallest bore that the block will clean up? Now lets get real. Run what you got. We are talking street car, young man, everyday driver, pump gas and decent mpg so he can afford to drive it. You basically want to build a 1972, 9 to high 8 to 1 compression ratio 340 with a 318 block. Forget horsepower. Get the pistons you first thought of if you need to bore the block. Use the 360 heads. Get a hydraulic cam and lifters somewhere in the .450 to .500 lift and 210 to 225 duration and a double roller timing chain. Find a used 340 intake, then go with a carb to fit the intake. Have the distributor recurved for high performance. Add a windage tray and high pressure oil pump relief spring. Balance the pistons, rods, and crank. 8 1/4 rear will be fine and the 3.21 gears are perfect. No need for low first gear trans, find a decent used 904 or 998 and get that car running and Enjoy.

I will get the casting numbers for you after school i really like this

 

[carmart1975]

If you plan on gears down the road and 3.21 are temporary could run more cam and live with the compromise or or swap in new bigger cam when doing rear end swap.

What gears be willing to run with the 8 3/4?

What would you recommend with a big cam

 

[carmart1975]

I live in Canada our money doesn't go as far. But I'd start with a decent running magnum preferably 5.9l (360) but a 5.2l (318) will work cause they got decent cr and head is capable to make 400 hp as is with a reasonable cam, on the high end of reasonable. A little port work and maybe some milling get away with less cam and or make more power and can always do an aftermarket head swap down the road for more power.

Price out the various ways to get there pick best one that suits you.

That is also a idea

 

[rumblefish360]

Ok thanks

Also… a flat top offers better flame propergation where the dome may-MAY inhibit the flame travel. This is dependent on some height, shape and sharp edges.

Sometimes a dome can not be used because of its height and shape is not going to work/fit with a closed chambered head, like an edelbrock. They can work and probably do best with an open chambered head like the early X, J etc heads.

For a good compression ratio on a street machine, 10-1 - 10.5-1 is what you’re looking for. This will run on 93 octane.

 

[273]

To show the up hill battle with gears your against, this will be with 27" tire hitting peak hp at finish line no converter slip calculated. Obviously you don't have to gear for max 1/4 mile time but will shows how compromised of gear choices we choose.

400 hp 318 make 400 hp around 6000 rpm and 360 at 5300 rpm for comparison sake.

Say we cover the range of 100 to 110 mph in the quarter mile. Gears are rounded.

318 @ 100 needs 4.88 gears to hit 6000rpm
318 @ 110 needs 4.30 gears to hit 6000rpm

360 @ 100 needs 4.30 gears to hit 5300rpm
360 @ 110 needs 3.91 gear to hit 5300rpm

For those that talk/see in torque say the 318 and 360 are making 1.2 lbs-ft per cid.

318 = 382 lbs-ft, 360 = 432 lbs-ft , 382 x 4.88 = 1552 lbs-ft to the tires, and 432 x 4.30 = 1548 lbs-ft to the tires, practically the same.

3.21 @ 100 = 3995 rpm
3.21 @ 110 = 4394 rpm

Need some kind of stroker big block to hit 400 hp at these rpm.

Bottom line 3.21 gears would be optimal for like a 400 hp 470-500 cid engine and even though both a 400 hp 318 vs 360 need deeper gears the 360 would be a lot better off with 3.21 vs 3.91/4.30 gear than 318 with 3.21 vs 4.30/4.88 gear.

Not saying build a bigger engine, just showing how much of an up hill battle gearing wise a decent hp smaller displacement is up against, imagine how much gear a 400 hp 273 would need.

(400 hp 273 @ 7000 rpm = 110 mph = 5.13 and 100 mph = 5.62)

 

[RogerRamRod]

I know the original post said 318. 3K budget and 400HP goal, I'd say start with 5.9.
I'd like to build a 318 for fun myself, I get tired of hearing hearing Frod & Chebby guys griping 302 and 305-whats mopar got, gotta go so much bigger, thats cheating.
Hell, I'd also like to do a Slant.
But reality says for 3K, A Magnum right from the yard will probably even still have good hone marks, not be all clapped out, & just need some add-ons, & a lot less work.

You gotta figure Trans, Brakes, & suspension too. I know thats not in the 3K expectation, but you need to be taking care of that stuff too.

 

[a-bodyguy]

3k budget= 9.5 to 1 comp 262 air gap used 750 vac sec used 360 heads 2.02 valves 315 hp give or take
nitrous gets you another 100
thats about the combo i ran in 1980 in a 68 dart 270 -318- 8 3/4 3.23s back then it sucked the paint off most everything on the street very quick out of the hole if they spun they lost
gm toliets spin/wheel hop not many fast fords only a few

 

[carmart1975]

i do not understand the trend of why everybody all of a sudden wants to buy cams based on how they sound.

who gives a rat's patootie what it sounds like! how it runs is far more important unless you spend your time idling around the fairgrounds or revving your nuts off in burger joint parking lot.

there's no one answer to which cam to use. there are general recipes that are accepted as combos that work well together, or some rules of thumb, and ideas and suggestions. but you need a lot of additional information to make an informed decision.

bang for the buck is choosing the right cam for the combo the first time and not buying one all willy-nilly, finding out that it sucks, hating life when you have to drop that loot and do it all again.

Its a teen thing like if you have a big cam it mens its fast I guess

 

[66fs]

Its a teen thing like if you have a big cam it mens its fast I guess

Factory 340's humiliated so many cars. If you know, High Performance can not be hidden. I worked at a Rental Car company in FL while I was in college. One of my friends was a Chevy guy, so I told him to buy a white 72 Nova when it's time came to be sold. I could hear it had a "Corvette" 350 in it rather than the junk 350s most Chevies had. There is a lot in the combination, not just a couple parts. If it is fast and you can't afford to drive it, or it stinks driving it around town it won't matter how fast it could be.

 

[a-bodyguy]

Its a teen thing like if you have a big cam it mens its fast I guess

It was so fun sucking the paint off the (teen thing) with my setup back then
the money made street racing it paid for the car and the build
a 262 comp sounds healthy in a 318 anything bigger without spray with 3.21s will be slow from 0 to 40 mph
races are won 0 to 40 mph
although todays newer stuff is faster then the old cars v6 mustangs mid 13s

 

[carmart1975]

To show the up hill battle with gears your against, this will be with 27" tire hitting peak hp at finish line no converter slip calculated. Obviously you don't have to gear for max 1/4 mile time but will shows how compromised of gear choices we choose.

400 hp 318 make 400 hp around 6000 rpm and 360 at 5300 rpm for comparison sake.

Say we cover the range of 100 to 110 mph in the quarter mile. Gears are rounded.

318 @ 100 needs 4.88 gears to hit 6000rpm
318 @ 110 needs 4.30 gears to hit 6000rpm

360 @ 100 needs 4.30 gears to hit 5300rpm
360 @ 110 needs 3.91 gear to hit 5300rpm

For those that talk/see in torque say the 318 and 360 are making 1.2 lbs-ft per cid.

318 = 382 lbs-ft, 360 = 432 lbs-ft , 382 x 4.88 = 1552 lbs-ft to the tires, and 432 x 4.30 = 1548 lbs-ft to the tires, practically the same.

3.21 @ 100 = 3995 rpm
3.21 @ 110 = 4394 rpm

Need some kind of stroker big block to hit 400 hp at these rpm.

Bottom line 3.21 gears would be optimal for like a 400 hp 470-500 cid engine and even though both a 400 hp 318 vs 360 need deeper gears the 360 would be a lot better off with 3.21 vs 3.91/4.30 gear than 318 with 3.21 vs 4.30/4.88 gear.

Not saying build a bigger engine, just showing how much of an up hill battle gearing wise a decent hp smaller displacement is up against, imagine how much gear a 400 hp 273 would need.

(400 hp 273 @ 7000 rpm = 110 mph = 5.13 and 100 mph = 5.62)

So really what yall been saying i just need to sell what j have and get a 5.9 mag

 

[carmart1975]

It was so fun sucking the paint off the (teen thing) with my setup back then
the money made street racing it paid for the car and the build
a 262 comp sounds healthy in a 318 anything bigger without spray with 3.21s will be slow from 0 to 40 mph
races are won 0 to 40 mph
although todays newer stuff is faster then the old cars v6 mustangs mid 13s

Thats so true though

 

[carmart1975]

what year 5.9 mag should i get

 

[Dan the man]

So really what yall been saying i just need to sell what j have and get a 5.9 mag

And a different oil pan and oil pump pick up tube as the pan on the magnum won't fit your cars chassis

 

[carmart1975]

go here and drop in your zip code: Quality Discount Auto Parts | Salvage Yards | LKQ Pick Your Part

c'list, offer up, farkbook, classifieds here, swapmeets. the parts are out there, it's just a hustle to get them.

you can attach pics to the message bodies here in thread. "attach photos" or thru external link (imgur). but if you provide the PN off the heads (it's on the runner in between the valve springs) you can google that or somebody here can tell you what they are. measure the valves tho, a lot can change in 40 years.

there is an absolute TON of info here, the search function is decent if you're specific in the query but you can get better results with an enhanced google search {how to pick a cam for a 318 forabodiesonly(dot)com} will turn up excellent results.

sorry if we come off a little gruff, but we know the realities of the game and we hate to see people waste hard earned money and invest blood sweat and tears into something that's a mistake we've all made before.

i don't know how far you're into that 318, but if it's not a boat load you might be better off packing that in and trying to get a few doubloons for it and pivot over to 5.9 that would likely be cheaper and easier to reach your 400hp goal.

i love 318's and i think they're fun builds, but if you want to make big power for cheap, you need to start with cubes and the magnum has the added benefit of great flowing heads.

that being said, a 300hp 318 in a light a-body is a blast. and that's doable on a beer budget.

i took a look at the pick a part and i think i will go with a 5.9 mag form there but what year mags should i look for

 

[carmart1975]

And a different oil pan and oil pump pick up tube as the pan on the magnum won't fit your cars chassis

i was planing on that thank you

 

[carmart1975]

I think that post 95 and 96 give the best suggestions. Also the op will have to upgrade the brakes.

i do already have good breaks i have disks up front and drums out back what do you thing

 

[273]

i took a look at the pick a part and i think i will go with a 5.9 mag form there but what year mags should i look for

Shouldn't matter there all practically the same.

 

[RustyRatRod]

I would build a good bottom end with a set of flat tops level with the deck.

id build that bottom end with main studs and wavelock rod bolts
id balance the bejeezus out of it crank and balancer, rods end to end, rod pin and piston weight if i had the option id choose the best set of 8 rods out of 2 motors small end in the middle of the small end casting etc not the gnarly looking, wonky 2 you find in each set

id use the King bearings race bearings
id do all the core/freeze plugs
i'd build it with clearances in middle of the tolerance
Id get a good harmonic balancer a known brand
id get a romac timing set, IWIS roller chain, a timing set where i can trust that the keyways and dots will be where they should be....! with some of the other big names you can't
i might..... put in a windage tray or a crank scraper
id match port my oil pump to the block
i'd make sure my pickup was solid
id put in a sump baffle
id measure exactly the required quantity of oil into that sump and make sure my dip stick read just below max. pull out and re site the dipstick tube if necessary
i'd have a new water pump
i'd bluprint my stock oil pump
new piston and relief spring
new senders
i'd paint it nicely
id tumble and clean up the chrysler hardware the screws with the "lead into the threads" so putting on sump and fuel pump is easy
id get either a rebuilder orginal carter pump and rebuild it or a new carter pump

changing the rod bolts means you have to have the rods resized and checked...
studs and rod bolts torqued to ARP spec not standard bolt spec
id run a clutch fan and standard alternator. its too easy to buy a **** electric fan set up

Id bolt on the 318 heads and a 4bbl inlet
id use the cast iron exhaust manifolds and id merge the collectors way back
id put in a standard dizzy and cheap HEI set up i.e mid 70s chevy 6 truck coil + and napa hei module
dizzy will potentially need a recurve

and see how it goes

the small valve 318 heads combined with the higher CR from the zero deck pistons and a small 600cfm carb will give you a wide torque curve that is just gooood fun around town...

once this is done you can do what ya like with cam heads inlet in future
and you can plan and save all while driving the car, cruising and going to shows

short block done ready for its next upgrade is a good place to be
and you have a benchmark to measure your upgrades against
what does good look like and what is better.... if you don't know you can't assign a bang for buck value to your upgrades

dave

There's 3/4 or more of his budget GONE in the first paragraph. I mean seriously, yall need to pay attention here.