1971 318 build

Penstarpurist

Well-Known Member
Joined
Oct 28, 2016
Messages
1,313
Reaction score
627
Location
Salem
Well as alot of you know from my crankshaft endplay thread we are having to rebuild the engine from my sons 1971 Plymouth valiant 2dr. It's got the original 318 in it, so he opted to get it rebuilt. The crankshaft was trashed from the thrust bearing failure, he pulled a good turnable crank from his '68 fury engine that was totaled. Looks like it is going to be bored .30 going to order the forged scat rods, forged pistons, the edelbrock upper end kit with the aluminum heads and intake with the cam and lifters they sell as part of the kit. I'll get the specs on it. He's going to have the machine shop do the short block rotating assembly build out for it. He's hoping to see 450 hp. The car already has dual 2.5 exhaust with x pipe, new edelbrock 650cfm carb. Though I am working on him to go efi, as he's already taking the gas tank out to replace it with a new one, good time to plumb it for the efi. Picked up a stage 2 firm feel steering box, as the guys are basically local to us. 3.55 gearset in an 8.75 rearend.
 

RustyRatRod

I was born on a Monday. Not last Monday.
FABO Gold Member
Joined
Jun 7, 2010
Messages
95,148
Reaction score
84,901
Location
Georgia
450 HP is a tall order for a stock stroke 318 even with those goodies. You didn't say stroker, so I assume stock stroke. Now throw a 4" arm in it and that changes stuff.
 

Syleng1

Karma is real and Life is short...
FABO Gold Member
Joined
Jul 5, 2005
Messages
2,809
Reaction score
2,566
Location
North Franklin, CT
From a person who has reached 450 HP with a 318.... it’s big money. 300 - 350 HP is a stretch for stock bore and stroke on a 318.

the engine is just a big air compressor and the 318 needs bigger. Everything. BUT stroker kits make that dream a reality. IMHO
 

toolmanmike

Moderator
Staff member
FABO Gold Member
Joined
Jan 18, 2006
Messages
74,077
Reaction score
72,614
Location
Office
300 horse is pretty easy. 350 gets a little more radical. 400 horse can be done and with aluminum heads you may get close. What cam does the Edelbrock kit have?
 

MOPAROFFICIAL

Well-Known Member
Joined
Jun 1, 2016
Messages
12,447
Reaction score
15,904
Location
Hiatus
You can build 300-350hp fairly easy, real world, with some 360 heads, mag or not.
Dont need much cam, dont need 10.1 comp or porting.

Combo from the carb down through the trans , rear diff and to the tire size will make the ultimate diff.
 

Penstarpurist

Well-Known Member
Joined
Oct 28, 2016
Messages
1,313
Reaction score
627
Location
Salem
450 HP is a tall order for a stock stroke 318 even with those goodies. You didn't say stroker, so I assume stock stroke. Now throw a 4" arm in it and that changes stuff.
We may have to go with the 4" arm to get into the numbers then. I had mentioned the 450hp mark as edelbrock had stated in their kit that it would 415 hp engine with their kit. And I know that's probably more of a meaning of "a potential" if all the other components are there. Before we order anything we will do more research to achieve those numbers. I'll get the specs on the cam.
 

RammerJammer75

Well-Known Member
Joined
Aug 28, 2020
Messages
1,458
Reaction score
1,910
Location
Kingsport, TN
upload_2020-10-6_11-42-22.png

Is this the kit?
 

Penstarpurist

Well-Known Member
Joined
Oct 28, 2016
Messages
1,313
Reaction score
627
Location
Salem
I checked it out more. I had only really listened to my son on it. I see now its starting with a 340 at 9:5.1 compression
 

Syleng1

Karma is real and Life is short...
FABO Gold Member
Joined
Jul 5, 2005
Messages
2,809
Reaction score
2,566
Location
North Franklin, CT
As I sit here and reread this and many other posts on my lunch break. I always come back to what a old racer once told me. It’s not so much the horsepower or torque you need. It’s the power to weigh ratio that wins the race.

Honestly, most light cars like a Duster, Dart or second gen Barracuda are light enough that a 300 hp engine on the street will destroy most stuff with the right gearing and tire size. A 12 second street car is insanity fast on the street (1/4 mile) but what good is it on the street when temp, traction and fuel is so unpredictable day to day. Go to the track and you may not know conditions till you get there but then you adjust and move forward. On the street the pavement changes from stop light to stop light. Let alone temps from trees shading the road or water run off. In other words- too many variations to play with. A good and solid car that is sexy, swift and reliable is so much better than a car that runs 11’s but breaks down hitting a speed bump day to day. Build your car how ever you like. But if your need to brag about numbers is what you are going for then drop a 426 hemi in that car and show them all up. Lol! Good luck with your quest for the car you two desire. It’s the journey and not the destination.:thumbsup:
 

Penstarpurist

Well-Known Member
Joined
Oct 28, 2016
Messages
1,313
Reaction score
627
Location
Salem
Syleng1 that's well said. I think the motivation for my son is him wanting a car that would rival my big block duster and my wifes srt8 challenger. Lol. I think the challenger while an impressive car, is a heavy one compared to his valiant. And the big block duster, while a big engine in a light gutted out car isnt a fire breathing engine. It's just a mild build in a light car. So I think your right, put together a well built, but reliable street car that can dominate most cars when the opportunity comes but still be a summer driver. Definitely a wise old racer your friend was. Thanks.
 

rumblefish360

I have escaped the evil Empire State!
FABO Gold Member
Joined
Jun 21, 2005
Messages
46,387
Reaction score
19,376
Location
Florida
Yes that would be the kit.
Do NOT! Use that cam.

I do not think 450hp for a 318 is a tall and hard order to fill. I do think the stock Edelbrock heads are up n need of some serious porting along with the intake and a nice 1-3/4 tube header into a well thought out exhaust system should be used.

Your camshaft, IMO, should not only be a little bit larger but you need to grab a more aggressive lobe with as much lift as you can use on the cylinder heads flowing abilities. Look to a good solid flat tappet. A solid roller would be easier to find the ramp rate but it is kind of pricey to purchase it and the supporting gear for it.

Do NOT be intimidated by the lack of cubic inches (perhaps a larger overbore?) but realize it will take more RPM to get to the goal. Something 3.55’s may not like and require a good custom stall converter.

Go for it.
 

rumblefish360

I have escaped the evil Empire State!
FABO Gold Member
Joined
Jun 21, 2005
Messages
46,387
Reaction score
19,376
Location
Florida
To rival the other cars, a hair dryer super charger is the easy button. Look at”TorqueStorm” for this route.

Oh! And make sure the oiling is well looked after!!!!
 

RustyRatRod

I was born on a Monday. Not last Monday.
FABO Gold Member
Joined
Jun 7, 2010
Messages
95,148
Reaction score
84,901
Location
Georgia
We may have to go with the 4" arm to get into the numbers then. I had mentioned the 450hp mark as edelbrock had stated in their kit that it would 415 hp engine with their kit. And I know that's probably more of a meaning of "a potential" if all the other components are there. Before we order anything we will do more research to achieve those numbers. I'll get the specs on the cam.

Here's how "I" would approach this. First, IMO, dyno numbers are useless as tits on a boar hog. Nothing more than bench racin fodder for probably over 90% of the people out there. My approach would be simple. Handle it much like the Mopar Performance recipes in the MP engine manual. Decide on a given ET and build the whole CAR to be that quick. "However" quick that is. Just one man's opinion.
 

rumblefish360

I have escaped the evil Empire State!
FABO Gold Member
Joined
Jun 21, 2005
Messages
46,387
Reaction score
19,376
Location
Florida
From RustyRatRod,
My approach would be simple. Handle it much like the Mopar Performance recipes in the MP engine manual. Decide on a given ET and build the whole CAR to be that quick. "However" quick that is. Just one man's opinion.
I’ll second that opinion. While the MP cam listed maybe impossible to find or stupid expensive, a good substitute can be made. I also suggest a Edelbrock RPM (AG or not, your call) instead of a 6 pack. But the rest is spelled out very well.

Click here—> “Speed Tips” from MP/DC Hustle Stuff

If there is a problem reading it, contact me.
 

AJ/FormS

68 Formua-S fastback clone 367/A833/GVod/3.55s
Joined
Jan 19, 2014
Messages
23,755
Reaction score
11,067
Location
South-Central Manitoba,Canada, 900ftelevation
I wanna say;
by the time you finish spending all that money on 318 cubes, you couldda had a closed-chamber, alloy-headed, near zero-deck 360, with a cam two or three sizes smaller, and end up with a 12 second street car on street tires that gets phenomenal mileage with 87E10.
But Hey, what do I know.
With a 223*cam, I drove 2.5 hours to the track, turned a 106@12.9 in full street trim. Only successful run of 4. Turned around and went 2.5 hours home.
My 367 fell together doing that, with zero tuning. near zero-deck, near 10.7, exactly 87E10..
@3650, my street weight, and 900 ft elevation, the Wallace Calculator says it takes 335 hp to do that. It was a plain-jane, flat torque, flat power, rev to the moon; Daily Driver.
But I'm not gonna say that out loud, cuz Sure as heck somebody is gonna be mean to me.
The point is this;
1) you will spend less money to get to 350hp with a 360 than you will with a 318 even if you consider having to buy a 360 core. and
2) the 360 will be gobs more fun, be able to run less gear, less stall, and haul a trailer, and
3) the 360 will spin street tires to the top of second gear ..... at least, with 3.23s and an auto.and
4) the 360 will get hands down better fuel mileage with a 223@050 HFT cam; even more with a solid
5)with 3.23s the 360 will cruise at 65=2600@ zero-slip. You can't even run 3.23s with a 350hp 318. Well you can but;
1) in first gear she will hit 60@6500 (10% slip),Way beyond the powerpeak, so think slow ET, or
2) in second ,she will hit 60@3850 (10% slip),on a 5500rpm power peak; not even up to the TorquePeak yet, so again, think slow ET.

I like Rumbles comments as to;
Do NOT! Use that cam.

Your camshaft, IMO, should not only be a little bit larger but you need to grab a more aggressive lobe with as much lift as you can use on the cylinder heads flowing abilities. Look to a good solid flat tappet.

Oh! And make sure the oiling is well looked after!
 

rumblefish360

I have escaped the evil Empire State!
FABO Gold Member
Joined
Jun 21, 2005
Messages
46,387
Reaction score
19,376
Location
Florida
I wanna say;
by the time you finish spending all that money on 318 cubes, you couldda had a closed-chamber, alloy-headed, near zero-deck 360, with a cam two or three sizes smaller, and end up with a 12 second street car on street tires that gets phenomenal mileage with 87E10.
But Hey, what do I know.
With a 223*cam, I drove 2.5 hours to the track, turned a 106@12.9 in full street trim. Only successful run of 4. Turned around and went 2.5 hours home.
My 367 fell together doing that, with zero tuning. near zero-deck, near 10.7, exactly 87E10..
@3650, my street weight, and 900 ft elevation, the Wallace Calculator says it takes 335 hp to do that. It was a plain-jane, flat torque, flat power, rev to the moon; Daily Driver.
But I'm not gonna say that out loud, cuz Sure as heck somebody is gonna be mean to me.
The point is this;
1) you will spend less money to get to 350hp with a 360 than you will with a 318 even if you consider having to buy a 360 core. and
2) the 360 will be gobs more fun, be able to run less gear, less stall, and haul a trailer, and
3) the 360 will spin street tires to the top of second gear ..... at least, with 3.23s and an auto.and
4) the 360 will get hands down better fuel mileage with a 223@050 HFT cam; even more with a solid
5)with 3.23s the 360 will cruise at 65=2600@ zero-slip. You can't even run 3.23s with a 350hp 318. Well you can but;
1) in first gear she will hit 60@6500 (10% slip),Way beyond the powerpeak, so think slow ET, or
2) in second ,she will hit 60@3850 (10% slip),on a 5500rpm power peak; not even up to the TorquePeak yet, so again, think slow ET.

I like Rumbles comments as to;

Thanks AJ, and while not being mean....

They have a 318 & wish to build it. Not a 360. There building what they have. Help them build what they have instead of steering them into spending money on what they don’t have. Why? Because it is what they want to do.
 

toolmanmike

Moderator
Staff member
FABO Gold Member
Joined
Jan 18, 2006
Messages
74,077
Reaction score
72,614
Location
Office
Thanks AJ, and while not being mean....

They have a 318 & wish to build it. Not a 360. There building what they have. Help them build what they have instead of steering them into spending money on what they don’t have. Why? Because it is what they want to do.
Easy to get sidetracked when talking about building 318's.
 

rumblefish360

I have escaped the evil Empire State!
FABO Gold Member
Joined
Jun 21, 2005
Messages
46,387
Reaction score
19,376
Location
Florida
It happens on every 318 thread. The hoard pushes the poster towards a 360. Practically shaming them into doing it.
 

73golddusterkid

Gold Duster Kid
Joined
Feb 24, 2008
Messages
199
Reaction score
37
Location
Kentucky
It happens on every 318 thread. The hoard pushes the poster towards a 360. Practically shaming them into doing it.
I've built a few 318's and there's nothing wrong with them at all. I personally feel like they scream to 6,000 rpm and above with minimal effort!
 

273

Well-Known Member
Joined
May 14, 2012
Messages
4,787
Reaction score
2,422
Location
Ontario
Well as alot of you know from my crankshaft endplay thread we are having to rebuild the engine from my sons 1971 Plymouth valiant 2dr. It's got the original 318 in it, so he opted to get it rebuilt. The crankshaft was trashed from the thrust bearing failure, he pulled a good turnable crank from his '68 fury engine that was totaled. Looks like it is going to be bored .30 going to order the forged scat rods, forged pistons, the edelbrock upper end kit with the aluminum heads and intake with the cam and lifters they sell as part of the kit. I'll get the specs on it. He's going to have the machine shop do the short block rotating assembly build out for it. He's hoping to see 450 hp. The car already has dual 2.5 exhaust with x pipe, new edelbrock 650cfm carb. Though I am working on him to go efi, as he's already taking the gas tank out to replace it with a new one, good time to plumb it for the efi. Picked up a stage 2 firm feel steering box, as the guys are basically local to us. 3.55 gearset in an 8.75 rearend.

https://www.hotrod.com/articles/0810phr-chrysler-318-engine/

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


post #27
Magazine Builds
 

Wyrmrider

Well-Known Member
Joined
Sep 5, 2016
Messages
3,611
Reaction score
1,773
Location
los angeles
just pencil it out both ways
just because you can do it does not mean you should
A 360 magnum may be less expensive to buid even if you have to buy a core
or just stick one in and go
and do not use that cam even if it's free
 

273

Well-Known Member
Joined
May 14, 2012
Messages
4,787
Reaction score
2,422
Location
Ontario
I wouldn't worry about final power numbers just go with 9.5-10.5:1 depending on cam the edelbrock heads and airgap. I agree don't go with there cam and go with a good stall company probably make or break your combo.
 

rumblefish360

I have escaped the evil Empire State!
FABO Gold Member
Joined
Jun 21, 2005
Messages
46,387
Reaction score
19,376
Location
Florida
just pencil it out both ways
just because you can do it does not mean you should
A 360 magnum may be less expensive to buid even if you have to buy a core
or just stick one in and go
and do not use that cam even if it's free
Another 318 hater.....
 
Top