Dust off your crystal ball and GUESS the horsepower !

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Kern Dog

Kern Dog

Build your car to handle.
FABO Gold Member
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Granite Bay CA
I have been asked to build a car for my nephew.
We are using a Duster, either a 71 or a 74, it has yet to be determined. I have one of each and both will require about the same amount of work to the body.
Normally, I default to a 360 for the A bodies that I have built to sell because in stock form, they make more power than any stock 318.
This will be my nephew's first car and it will be a V8. I think that I should play it a bit safe. It will have front disc brakes and upgraded suspension.
I have a 1969 318 from a Satellite. It has never been rebuilt but it ran great when I got it years ago. These were gross rated at 230 HP but later the essentially unchanged engines were net rated at 150 HP. I have a set of '308 heads to use along with an iron Thermoquad intake, several Thermoquads to choose from too.
My thoughts are to pull the 318 apart and if the cylinders aren't too worn, I could dingle ball hone the cylinders and screw it all back together with new rings, bearings and gaskets. I've considered using a 340 spec cam, cast iron exhaust manifolds and 2 1/4" dual exhaust all the way to the rear bumper.
I've always thought that what held the 318s back was the restrictive heads and tiny camshafts they had and that with better heads, cam, induction and exhaust, they could be comparable to a 340.
What do you think? Is it possible to generate 250, 275 HP out of a smooth running 318? I'll be using a 904 based transmission, most likely a low gear set later 904. The axle will be an 8 1/4" with 3.21 gears. I think that leaving it a one legger is probably safer for now.
 
Kern Dog said:
I have been asked to build a car for my nephew.
We are using a Duster, either a 71 or a 74, it has yet to be determined. I have one of each and both will require about the same amount of work to the body.
Normally, I default to a 360 for the A bodies that I have built to sell because in stock form, they make more power than any stock 318.
This will be my nephew's first car and it will be a V8. I think that I should play it a bit safe. It will have front disc brakes and upgraded suspension.
I have a 1969 318 from a Satellite. It has never been rebuilt but it ran great when I got it years ago. These were gross rated at 230 HP but later the essentially unchanged engines were net rated at 150 HP. I have a set of '308 heads to use along with an iron Thermoquad intake, several Thermoquads to choose from too.
My thoughts are to pull the 318 apart and if the cylinders aren't too worn, I could dingle ball hone the cylinders and screw it all back together with new rings, bearings and gaskets. I've considered using a 340 spec cam, cast iron exhaust manifolds and 2 1/4" dual exhaust all the way to the rear bumper.
I've always thought that what held the 318s back was the restrictive heads and tiny camshafts they had and that with better heads, cam, induction and exhaust, they could be comparable to a 340.
What do you think? Is it possible to generate 250, 275 HP out of a smooth running 318? I'll be using a 904 based transmission, most likely a low gear set later 904. The axle will be an 8 1/4" with 3.21 gears. I think that leaving it a one legger is probably safer for now.
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Gonna do any milling for cr ?

250 hp is a pretty easy goal, no matter what it makes should be a decent setup for your nephew.

Here's a stock low cr 318 long block makes 282 hp with 4 bbl headers and a xe262h cam.
https://www.hotrod.com/articles/mopp-0312-318-long-block-bolt-ons/
 
i think 250~270 is possible and a relatively easy goal to attain with those parts.

you'll be down a little power across the board because of the stock logs.

rethinking the cam might net you more torque lower down in the range and give better driveability/street manners. newer modern grinds take advantage of better lobe design and more aggressive ramps and if you combine that with a split pattern you can get some real decent performance from these smaller cams.

because it's a 69 motor, it's got decent compression. i wouldn't touch a thing in that department, that way you're not hemmed in on having to always run 91
 
junkyardhero said:
i think 250~270 is possible and a relatively easy goal to attain with those parts.

you'll be down a little power across the board because of the stock logs.

rethinking the cam might net you more torque lower down in the range and give better driveability/street manners. newer modern grinds take advantage of better lobe design and more aggressive ramps and if you combine that with a split pattern you can get some real decent performance from these smaller cams.

because it's a 69 motor, it's got decent compression. i wouldn't touch a thing in that department, that way you're not hemmed in on having to always run 91
Click to expand...
You wouldn't mill the 360 heads a little to keep stock cr ?
 
Thanks, guys.
The kid is 13 now. The goal is to have the car drivable by the time he is ready to get his learner's permit at 15 1/2 years of age.
Plenty of time and I'm retired so the only thing holding me back is me.
Jaxon wants to be involved in the build.

IMG_3919.JPG


I never had kids so this is something that I have wanted for over 30 years. I helped a brother in law build another Duster but he lost interest in the car and I bought him out.
This time, I'm not placing any expectations. If Jaxon's interest stays strong, the car will be a great experience for both of us. If he loses interest too, I guess I'll be buying out another one to eventually sell. I enjoy the building of them anyway.
 
273 said:
You wouldn't mill the 360 heads a little to keep stock cr ?
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I would mill them at least enough to compensate for the thicker Fel Pro head gaskets. The goal would be for the engine to run fine on 87 octane ethanol infused gasoline.
An iron headed 318 should be able to handle 8 3/4 to 9 to 1 compression on 87.
 
Get compression to 9.5 and an honest 300HP isn't out of touch.....with a better matched camshaft and headers.
 
If we did, it would be fitted with a carburetor. I wouldn't go through the trouble of trying to make the EFI system work.
 
You plan seem sound you don't want to start your nephew off with too much power and with a decent starter engine he can always add upgrades.
 
Kern Dog said:
If we did, it would be fitted with a carburetor. I wouldn't go through the trouble of trying to make the EFI system work.
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Correct. That's how I was talking about. If you could find one still in good shape and was a good runner, you could put a good intake and carburetor and headers with a good hot distributor with a loose curve and there's your 300HP. Problem is now, they are getting older and harder to find lower mileage examples.
 
btw, KD this sounds exactly like my latest build. 73 318, 68 heads, "340" cam advanced a little, topped up with an LD4B running thru stock manifolds. i haven't decided on the carb yet but it'll be between 600~625.

if it makes 280 i'd be tickled pink.
 
junkyardhero said:
btw, KD this sounds exactly like my latest build. 73 318, 68 heads, "340" cam advanced a little, topped up with an LD4B running thru stock manifolds. i haven't decided on the carb yet but it'll be between 600~625.

if it makes 280 i'd be tickled pink.
Click to expand...
750 Street Demon.
 
RustyRatRod said:
Correct. That's how I was talking about. If you could find one still in good shape and was a good runner, you could put a good intake and carburetor and headers with a good hot distributor with a loose curve and there's your 300HP. Problem is now, they are getting older and harder to find lower mileage examples.
Click to expand...

The 5.2 and 5.9s are still commonly found in junkyards out here. Durangos, trucks and vans are still coming in with them.
The roller cam would alleviate the likelihood of those cam and lifter failures.
I'd have to get one of those Crosswinds 4 barrel intakes. I'd need to do something about the fuel pump eccentric too. The Magnums sure seemed better at stopping oil leaks!

340six said:
267.8 hp
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01 A3.jpg


Yeah, I did mention using the crystal ball. I just didn't know what range is to be expected.
 
Kern Dog said:
The 5.2 and 5.9s are still commonly found in junkyards out here. Durangos, trucks and vans are still coming in with them.
The roller cam would alleviate the likelihood of those cam and lifter failures.
I'd have to get one of those Crosswinds 4 barrel intakes. I'd need to do something about the fuel pump eccentric too. The Magnums sure seemed better at stopping oil leaks!
Click to expand...
a 5.9 with a reground cam and the hong kong phooey intake is a hard combo to beat.

only problem is that you're almost gar-un-teed to need cam bearings and heads.

but if you put together the basics from the start you can have something that's perfectly serviceable and quite mellow with tons of potential to grow down the line.
 
RustyRatRod said:
Correct. That's how I was talking about. If you could find one still in good shape and was a good runner, you could put a good intake and carburetor and headers with a good hot distributor with a loose curve and there's your 300HP. Problem is now, they are getting older and harder to find lower mileage examples.
Click to expand...
If I recall, the Mopar Performance 360 crate engines came in 300 HP and 380. The 300 was supposedly a stock truck engine that was normally rated at 230 as installed in new trucks with catalytic converters and manifolds.
 
Get him this book for bathroom reading so he can nerd out. It will probably help him hold interest over time because he will have a good understanding of the mechanics. Who knows, he may want to become an engineer.
Do the math with him on each part of planning the build, so he gets a good feel for WHY he has to learn math in school.

 
Kern Dog said:
If I recall, the Mopar Performance 360 crate engines came in 300 HP and 380. The 300 was supposedly a stock truck engine that was normally rated at 230 as installed in new trucks with catalytic converters and manifolds.
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230-245 hp is net hp, they make about 300 hp in dyno trim so gross hp.
 
You KNOW he'll want the 360 (or 408). Tell him we're putting together a "performance" 318 for now.
Once you prove to be a safe, competent, self restraining driver (no tickets, no accidents, no friends in the car, no cellphone use), we'll talk about a hot 360.


Meantime, dingle ball the cylinders, and use what you already have. A DECENT running 318 is more than enough for a learning driver. Just make sure it's dependable, and STOPS.
 
Just curious.. why a 340 spec cam? Everything the OEM does/did is done with compromises.... lowest cost to build with acceptable power and/or efficiency... have someone spec a better cam.. BTW.. i put .028 compressed thickness head gaskets in my 318, every little bit helps.

P.S. i personally, for a first car would do a bone stock 318 for him... a 16 year old doesn't need more power til they learn to be safe :)
 
Icetech said:
Just curious.. why a 340 spec cam? Everything the OEM does/did is done with compromises.... lowest cost to build with acceptable power and/or efficiency... have someone spec a better cam.. BTW.. i put .028 compressed thickness head gaskets in my 318, every little bit helps.

P.S. i personally, for a first car would do a bone stock 318 for him... a 16 year old doesn't need more power til they learn to be safe :)
Click to expand...
Agreed. For a 16 year old I knew who had a 66 Dart, with a 318, "It's got BEEF!"
It's plenty to start out driving.
 
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