Making power out of the 318

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carmart1975

carmart1975

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so i recently got and 1973 small block 318 i am very new to mopar and was wondering what to do to the 318 i have every thing but the pistons the guy that i got it off of droped one and cracked it, i also have 360 heads that i would like to put on i am thinking about putting kb 167 pistons (0.40 over) in it, stock crank, stock rods and a rad cam with a lot of lope because i am a stupid kid, and stock 360 heads and then some kind of single plane intake and then a 750 double pumper i am really on a tight budget. is all of this possible or unrealistic.
 
Depending on the chamber volume and what they actually measure at, you could use kb399’s. They’re domed and could put your compression up higher where it won’t be a lazy low compression combo. What axle, gears and tire size does your car have? That has to be considered for your cam. Stall of converter?
 
Looks like you will be below 9:1 compression ratio. If you want a big cam I'd run more compression. 360 heads usually run around 72cc.
 
carmart1975 said:
so i recently got and 1973 small block 318 i am very new to mopar and was wondering what to do to the 318 i have every thing but the pistons the guy that i got it off of droped one and cracked it, i also have 360 heads that i would like to put on i am thinking about putting kb 167 pistons (0.40 over) in it, stock crank, stock rods and a rad cam with a lot of lope because i am a stupid kid, and stock 360 heads and then some kind of single plane intake and then a 750 double pumper i am really on a tight budget. is all of this possible or unrealistic.
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Your gonna get a lot of conflicting advice on 318's, you seem to be on the right track, i don't know about the single plane and lot of lope (possible depending on), but first before that what gears stall and what kind of performance and purpose are you looking for ? 318 need rpm to make decent power which like deep gears stall etc..
 
66fs said:
Looks like you will be below 9:1 compression ratio. If you want a big cam I'd run more compression. 360 heads usually run around 72cc.
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Zero deck some thin gaskets and heads milling, should be able to get cr needed?
Depending on his idea of loppy cam.
 
Power increases beyond 15-30...?
Change the heads for better flowing ones with a smaller "60cc" chamber, bump the cam to .500 lift and a min 274 adv dur..
 
Stock '69 318

Resized_20191202_092003_6592.jpeg


To this, simply add a 4 barrel.

20230124_110028.jpg


Same stock engine.
Go, Go, Go....


☆☆☆☆☆
 
Here we go...picks of stock bolt on krylon motors again...

I could be posting 360 pics and ya wouldn't know the difference if you couldn't see the dampener
 
eschew the single plane for a dual, the smaller cubes need all the help they can get in the down low and torque department. go less wild with the cam and try and stay around .475-ish and 260~275-ish duration. i think those pistons are fine for a mellow build and with the right headgasket you can probably get the compression to a decent number.

the heads are likely the most limiting factor, but will probably be fine for a mild build.

i wouldn't run a 750 DP with that kind of combo. i'm not saying it can't be done, or that it wouldn't be fun... but i think there are many other better choices.

a huge consideration is stall and gears. what do you have there currently? are you planning to upgrade those areas as well? those are a huge influence on overall performance.
 
If not open to running the required gear and stall, I'll build around the gear and stall compromise you set.
Main problem when building smaller displacement is they gonna need generally more gear stall rpm etc. for example a 318 will need about 13% more gear, stall, peak rpm etc.. Than a similar hp 360 to get similar performance (13% based on similar efficiency lbs-ft). Obviously efficiency can vary.
 
racerdan80 said:
Depending on the chamber volume and what they actually measure at, you could use kb399’s. They’re domed and could put your compression up higher where it won’t be a lazy low compression combo. What axle, gears and tire size does your car have? That has to be considered for your cam. Stall of converter?
Click to expand...
So currently I have a slant six so i will be getting a new trans i have a 8 1/4 with 3.21s and i will be getting a new converter with the correct stall for the cam that I get
 
273 said:
Zero deck some thin gaskets and heads milling, should be able to get cr needed?
Depending on his idea of loppy cam.
Click to expand...
If i zero the deck with the kb 167 or 399s will there be a problem and will the intake fit, right
 
junkyardhero said:
eschew the single plane for a dual, the smaller cubes need all the help they can get in the down low and torque department. go less wild with the cam and try and stay around .475-ish and 260~275-ish duration. i think those pistons are fine for a mellow build and with the right headgasket you can probably get the compression to a decent number.

the heads are likely the most limiting factor, but will probably be fine for a mild build.

i wouldn't run a 750 DP with that kind of combo. i'm not saying it can't be done, or that it wouldn't be fun... but i think there are many other better choices.

a huge consideration is stall and gears. what do you have there currently? are you planning to upgrade those areas as well? those are a huge influence on overall performance.
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What carb would you run?
 
carmart1975 said:
So currently I have a slant six so i will be getting a new trans i have a 8 1/4 with 3.21s and i will be getting a new converter with the correct stall for the cam that I get
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With a fairly lumpy cam and single plane lowest gear I'd go with is 3.91 on 26/27 inch tire, preferably in the 4.xx's.
 
Ok so maybe a dual plane because i half to daily the car to school its like 10 miles and of course Around town with friends so i would rater try to stay in the 3.20s and 40s i will eventually put a 8 3/4 so i will regear it then, its going to be a street/strip car I should have said that earlier my bad
 
carmart1975 said:
If i zero the deck with the kb 167 or 399s will there be a problem and will the intake fit, right
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Depends on how much you got to mill of to reach the cr goal (probably not overly a lot) , but just got to mill some off the intake side of the head. What's size cam you thinking ? similar to like a comp xe268h or xe275h etc.. ?
 
carmart1975 said:
What carb would you run?
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combo dependent, but a 625 carter (edelbrock) afb/avs covers a lot of territory. and dead simple to set up. cheap, reliable, abundant. works out of the box.

holley 1850 600 cfm. vac 2ndary, slam it on and go.

holley 3310-2(thru~6) for a 750 with metering blocks on the 2ndary and down leg boosters if you wanna get wild.

but again, combo dependent. if you're building a scoot around street cruiser for stop light eliminator saturday night action (read: compression, cam, stall, gears) then a 750dp is a perfectly cromulent choice.
 
zero deck the block, shave heads to desired compression with the flat tops! id run a mechanical 650 on a single plan if mostly race,..for street id run a 750 on a airgap! cam and matched converter, street gears 3:55 to 3:91 race 3:91 to 4:88s depending on 1/8th or 1/4!
 
With 3.21 and a moderate stall I'd stay under 220 @ 0.050" cam.
 
273 said:
Here's all the 318 plus for the 318 guys

318 Engine Build - A Parts Book 400HP 318 - Mopar Muscle Magazine

Mopar 318 Engine - Car Craft Magazine

Chrysler 318 Engine - Popular Hot Rodding Magazine

318 Small Block Build - How To - Hot Rod Magazine

318 Long Block Bolt Ons - Tech Articles - Mopar Muscle Magazine

https://www.hotrod.com/articles/0901phr-mopar-318-magnum-engine/

https://www.hotrod.com/articles/mopp-0311-318-engine-buildup-and-dyno-test/

How To Install A Hotter Camshaft - Mopar Muscle Magazine

https://www.hotrod.com/articles/mopp-0009-1985-dodge-dart/

Vintage Mopar Power! 550HP Chrysler Poly 318 V8 on the Dyno

318 head porting for the average joe

Porting small block 915 j-heads

Magnum head porting for the beginner

360 Engine Head Porting - Mopar Muscle Magazine

https://www.hotrod.com/articles/mopp-0002-porting-exhaust-smog-heads/

https://www.hotrod.com/articles/mopp-0507-cylinder-head-porting/

https://www.hotrod.com/articles/mopar-small-block-intake-manifold-flow-test/

https://www.hotrod.com/articles/0601em-intake/

https://www.hotrod.com/articles/10-critical-mopar-engine-building-specs/

https://www.hotrod.com/articles/mopp-0309-mopar-engine-rebuild-intro/

https://www.hotrod.com/articles/mopp-0308-adding-magnum-to-a-360-short-block/
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Here's some 318 articles
 
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