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#1
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360 build.
Next one..........since I cant bring myself to start on my 390, (want aluminum heads) I am looking into a cheaper option for more power, for now. A 360.
Here's what I got going so far. 360 block (74) 302 heads, Offey Dual port manifold. The 360 will get balanced, and have flat top TRW pistons, the 302 heads will be matched to a big port gasket, and so will the dual port. They also already have 1.88/1.60 valves in them. Carb is dwc's favorite, and Performer 750CFM.......... Supercomp headers will be installed, with a 2 1/2" X pipe exhaust, and some 24" glasspacks. Here are my hang ups, as always, camshaft. I am looking into a cam, that will perform between 2000 and 5000, Buuuuut, I want as much chop as I can get. Yup, I am sick of smooth idling, I want LOPE! (Cool old truck like this, needs to sound good too) Valvetrain. I am looking at the mancini iron adjustable rockers, anyone had these? I have a set of sharps, buuut, aluminum rockers in a truck motor......nahhh. Balancing, should I go internal, or external? Pro's and cons please. The vehicle, is a 74 D300, with 4.88's, and 28" tires. It will have a 2000-2300 stall converter too. |
#2
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360
My 360 had .030" over Arias flat tops with floating pins, Iron adjustable rockers,Heavy duty rocker shafts, Billet crank,Internal balance, flat tappet cam with 242 deg at .050" lift, .490 lift, Milodon gear drive, 3000 stall converter,Manual shift TF, 800 CFM TQ, Sheet metal ram intake. Hooker long tube headers,4.56:1 rear. Just for reference. Dan
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#3
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The carb will work, but not up to the level of a TQ and it's not my favorite. It ranks pretty low. If you'ld try one, you would see the difference. Your main problem will be the small port 318 heads and small valves. The 360 wont be able to breath and do it's job. But, just like Frank says, you'll do what you want, so why ask.
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#4
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You think it would make the torque to spin up a 2200 stall?
How did it run? SOUND? Hehe (re-living my teen years again, I guess) What brand of iron rockers? |
#5
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I have had thermoquads, and I ran into lean/rich problems between the cylinders, with a Performer manifold. Swapped for a 650 Holley, and it went away. I am sure it had nothing to do with the spreadbore design.
Anyway, the 302 heads are chosen, for they're closed chamber, and low/mid torque capability. Thye will flow close, if not with a stock J head, when done, and they dont have small valves, they have 1.88/1.60's.................... |
#6
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Those heads will work great, up to about 5000-5500 RPM. The carb isn't my favorite either, but I certainly don't think it's junk.
So, you're waiting to go with AL heads on your stroker eh? Do you remember our chat last night where you tried to talk me out of replacing my X heads with aluminum ones? Why the change of heart? Anyway, back to the questions you actually asked. Cam: You want power in the 2000-5000 range, but with lope. Cutting off the power at 5000 usually means a pretty short duration, and that means a smooth idle. The way to increase lope is to increase overlap, that means a narrower lobe center. Get a cam in the 260-270 degree range on the intake, but with about a 6 degree lobe center. That will give you the idle you crave, and still make power down low. Sorry, it will make power above 5000, probably to at least 5500 and maybe 5800. Hope you can live with that. Rockers: Iron is best on the street. You ignored my IM earlier today where I tried to tell you about a complete 273, with trans, for $100. That would be worth it for the rockers alone. Haven't used the Mancini, I'm sure they are fine though. Balancing: External is cheaper, internal gives you more flexibility if you decide to use a fluid damper or change converters later. Pick a priority and decide accordingly. |
#7
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I saw the 273 IM, you were offline................sheesh............
You better buy the damn thing! All I got to say. Wanna sell the rockers? LOL. As far as the X heads go, vs Aluminum, you sounded proud of the X heads, so why change them? (ellin ya, DLI can fix em!) So, were thinking a 270 (About) duration cam, with a 6* center huh? Somewhere about 500 lift. I will look into cams more this weekend, but it sure is looking like i will have to have one ground. As far as power, 5800 is fine, I have a fanclutch, and the alernator wil have a big pulley! Thanks guys, research continues.............. |
#8
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Quote:
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#9
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So? Did you buy the damn thing?
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#10
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Mallory slugs are expensive... So are HP flywheels. |
#11
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Still waiting to hear about fixing the pushrod hole. Meanwhile checked out a pair of 915s at a local shop. Both had cracks in the seat area. Those Edlebrocks are looking better all the time. |
#12
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I'll give you my opinion on the parts as you listed in the order you listed them. The 302's should be fully ported. Not so much made extra large, but certainly opened up for the task at hand. You'll not need to much more volume in the intake runners. The exhaust needs the most help. I think the 1.88 - 1.6 valves are a toss up depending on cam and converter choice. If your cam is in the 2200 RPM and up starting point of power, I think it will work. Weight of the truck could be an issue of how well it performs. There probably the right valve(s) for the job. Your choice on carb. (DW, isn't your fav. carb the T-Q like he said?) Super comps? There race headers. Were not racing this combo are we? Street headers! Cam shaft was covered well. Tight centerline on the cam will make it go chop chop chop like an ax. The iron rockers I've never used. Balanceing was covered well. Interanl gives the best results at the added expense. Is it worth it? Is this converter going to work with the cam? The spreadbore design carbs have allways had distribution problems. Nothing new. However, I think the 750 may not perform as well as the T-Q could. |
#13
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LOL, most don't like the dual port offey! Twice the main mixture, and leaner secondary mixtures really screw with people. I have a few places to cut, and drill, to make them perform better, whithout such a off the wall carburation.
The heads wil be cleaned up, most of the work will be done in the bowl area, not changing the shape, but cleaning up what is there. Fine line between the cam and converter, it wil be pulling trailers, and working hard, so I cant over do my converter, pone bit. (Working range will be in the 2800-4500 RPM's........so I can get a lot of cam in it, and be happy. Plus, I want it to sound nice, hehe. I will be balancing it internal, so I can swappety swap with 318';s, I don't plan on having this motor in the truck longer than a year, it will cost me about 80$ more to balance it internal, according to the machine shop. I already hyave the 750 EDL too, so that would be the reason............ AS far as the supercomps, the low gears will be running me in the midrange all the time, so I think they will be nice, and yes, it will be racing, up hills, from lights..............LOL The truck weighs about 4500............about what your magnum does, LOL, hard to believe! |
#14
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I would just balance the back half of the motor, and get the flex plate from B/M that will allow the 318 converter you have. Thats what I use on my motors, works good. Seems as luck would have it, I am constantly switching from 318 to a 360 to a 340, sometimes in one race season.
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#15
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Hum, heavy sucker. My Magnum weighs 3750 with the small block.
??? with a big block and headers ??? |
#16
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Remember that if...............
You go just a little BIG on the other parts, you can always tune it down a little with the LONG tube Hooker headers. That will restore some of your mid-range.
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#17
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Tarrbabe, could you explain more please? You mean a little big on the cam?
Rumble, my magnum, was 4200, with a 440, electric winders and seats, leather, and 3/4 tank of gas............... SOund about right? |
#18
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As in..........
if you add parts that kill some of your bottom end torque, you can use longer tubes on the headers or even a 1/8 inch smaller pipe to regain some of it.
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#19
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That is what I was thinking, with the small port heads too.
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#20
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How much heavier is a big block over a small block? How much does a gallon of gas weigh? How many gallon tank did you have? |
#21
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i think they have some 308 close chambers that came on the 360's. i have a friend that has a set i have looked at them and they look just like the 302's. but already larger ports.
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#22
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Quote:
Quote:
Here's a question. I am internal balancing my 360, can I use a 318 balancer? I cant think of a reason why not............. |
#23
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yeah, other wise it wouldnt be internal.
I would just balance the rear of the 360, no real need to do the whole dang thing. Thats just me. |
#24
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[QUOTE=dodgetruckboy] Gee, it's been four years.........but I think it was a 22 gallon? I had like 16 in it, probably, a gallon weighs about 5 pounds. I don't think a big block is more than 100 pounds more [QUOTE]
(Now why didn't that work?!? LOL) Your Magnum was a '79 then. I think a bg block is a bit more weight than a mere hundred. |
#25
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Yeah, it was a 79 XE, 360hi-po car. I tore apart a 400 cordoba, with a 400, and monglefied the 440 in the 79. Good car, I just wish I could have found one that had more life left.
Still have the doors, hood, rear lights and panels, and the trunk........waiting for another to pop up. Driving that big ol B was such a treat, I love those cars. |
#26
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I know of one for sale, up north. Do you really want one and ready to jump on it? PM me.
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#27
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AMA weights for the Magnum. Dan
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#28
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Now thats a cool post! Thanks buddy. I gotta save this.
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#29
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The 360 weighs 60 pounds more than a 318? really. Hmmmm.
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#30
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Quote:
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