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Discussion Starter #1 (Edited)
OK, I know a few of you have a 70's dodge 360.. i personally have 2, a 77 and a 78. I am starting to plan what I want to do with them, to make one motor. So what would you do to your 70's dodge 360?

Currently one motor has:
.010 over pistons
Summit rebuild kit
PAW RV Cam (i think)
Stock 2bbl intake
2145 Holley 2bbl
Engine has been sitting since late '98

Other motor:
Napa rebuilt 360 (some machine shop in modesto did it in '93)
Performer intake
Edelbrock Carb
engine was last run about 2 months ago, and about a year before that
Oil gets DARK black in about 1500 miles from carbon build up.

I also have a Pro jection fuel injection unit (minus the computor), 2 thrermo-crap's, a Q-jet, and some other junk laying around.

Both motors have under 30k miles on them.

My only plan so far is to spend under $400 on the motor, not including the Summit racing headers, and 40 series 2.5" Flows.

So have at it, what should I do for as little money as possible.

Garrett


BTW, i am keeping my eyes open for an 88-93 360.. so i can snag its heads.
 

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Performer intake and Qjet on whichever bottom end you like better. 308 heads and 759 or 761 cam (or the 782, not much difference) double-roller chain with tensioner, light centrifugal advance springs. You might be able to scrape up all the parts and gaskets for $400 if you're careful AND lucky. I've got your porting templates for those heads.
 

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I don't know what your mechanical aptitude is, so won't recommend. You're looking at about a kilobuck to have someone else do them. Don't start on a set if you can't afford to trash one (ie. only someone extremely good or an idiot would work on an original W2; but only an idiot would touch an original 340 T/A head). For heads that can be replaced readily (and the 308's are still available new) it's a question of how much they cost versus how badly you want them ported versus how likely you are to butcher one or thin it enough to have it crack six months later.
 

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Discussion Starter #5
I have a high mechanical aptitude, just never done it before. How much HP will i gain porting them over leaving them stock? There any good online articles on porting heads? If i really need help, I am sure i can get one of my buddys who have done it before to give me a hand.. tho, I think they have their own projects to deal with.

What about if I kept my stock heads?

options options options

Garrett
 

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Gain depends some on the parts combination. With the stuff listed above, the ported 308's with big valves are probably worth 100 hp over stock heads. Honestly, with the $20 porting templates for the 308's I think most people could turn out close to 50 hp over the same unported head with minimal risk. There's one very good online article on porting small Chrysler heads; don't recall the URL, but google should bring it up easily enough. Also the Standard Abrasives web site has a good writeup, naturally biased toward the use of their kit. I really prefer carbide burrs for most of the work. Takes about 40 hours to do a set.
 

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Discussion Starter #10
You also noted 3 different cams. Now which one do you think would work the best in a truck without an od, 4.10 gears, and 35" tires (34" actual higth).. which would mean i will be spinning about 3200 rpms at 75 on the highway... (i am still half waythrough the cam article)

Garrett
 

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For almost any shop to charge a kilobuck means that it takes some time and skill; if it was as easy as preparing a McLunch the price wouldn't be so high. :p The templates are specifically designed to guide someone who's never done head work before and allow them to expect good results. Drawback is they've got to be specially made for each casting. Going off on your own without experience or some kind of guide, you're likely to create as many problems as you solve and end up with no real net improvement.

On a set of the stock 360 heads a good home-port job is probably worth 15-20 hp. Depends some on what castings you have; the '78 Lil'Red Express had the best pre-swirl heads on a truck (unfortunately a move to run W2's on 'em from the factory got squelched). Biggest gains are seen by removing the extra material inside the valve seat, cleaning up the parting lines particularly at the bowl/runner junction, and smoothing the guide bosses. Still takes a lot of time, and good judgement; IMO it's worth the effort to do minor blending and cleaning up on almost anything, but aggressive removal of material should be avoided.

A graduate-level text in aerodynamics wouldn't hurt either but most treatments focus on steady flow, and in intake port and runner geometry we also have a set of dynamic acoustic-wave constraints to consider as well. A realistic model would be computationally expensive; naturally the manufacturers do this now on new designs, but traditionally hot-rod head porting has historically been a black art based on trial-and-error flowbench experimentation with lots of ruined heads, and people in that business have not been known to share accurate information freely.
 

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Hick said:
You also noted 3 different cams. Now which one do you think would work the best in a truck without an od, 4.10 gears, and 35" tires (34" actual higth).. which would mean i will be spinning about 3200 rpms at 75 on the highway... (i am still half waythrough the cam article)

Garrett
There's actually very little difference in those 3 cams; the question is whether you want to trade off a bit of high-end horsepower for a little more low-end grunt, or if you want the nostalgic feel of the old 340 stick.
 

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Discussion Starter #16
Question: Should i bother with rebuilding, or even going through the motor? I was thinking i should just take the 78 motor, put on the performer intake, and put on a good timing chain, and call it good? Should i even rebuild it? The engine will be out of the truck either way.

Also, what way should i put the fuel into the motor? Q jet (needs alittle work), Edelbrock 650 (works perfect), Holley 2245 (worked OK before), Thermoquad (needs a rebuild), or the 675 2d pro jection (needs a new computor)?

Thanks

Garrett
 

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I would try to find a set of cheap pistons to get the compression up to a reasonable level, a lot of 360s are out there with an actual compression ratio in the 7 to 1 range. I currently have a 360 going together with magnum heads just because they are the only reasonably priced closed chamber heads for making some decent squish. (some call it quench)
 

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txs said:
I would try to find a set of cheap pistons to get the compression up to a reasonable level, a lot of 360s are out there with an actual compression ratio in the 7 to 1 range. I currently have a 360 going together with magnum heads just because they are the only reasonably priced closed chamber heads for making some decent squish. (some call it quench)
.....and the deck hieghts side to side are horrable most of the time. sometimes so bad that 2 head gaskets were used on one side to even things out.:rolleyes:

decking the block and getting the compression up is definately necessary for a good building block.:beer:
 

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Discussion Starter #19
So the question still stands, what should I do for the very least amount of money to my engine?
As a side note, I do have a 413 sitting in the garage that i am tempted to bore .060 over and put in a larger stroke crank later on... so this engine may not stay in the truck for more than a couple of years.

Garrett
 
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