Opinions on 360 build

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74scamp360

74scamp360

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Ok guys so the original plan was to buy a running 360 that was cheap so that i could just drop it in and get the scamp back on the road. well we got into the 360 i bought and although it is running it really isn't in great condition inside, so i deceded i'm gonna pull the motor apart and give it a nice once over. My plan is to build a a nice little street motor without spending tons and tons of money, so after a little reaserch i came up with this combo and was wondering what you guys thought. So, stock crank and rods (sorry, stroker is not even close to being in the budget) with a set of TRW H116CP-20 pistons (http://www.flatlanderracing.com/trwchry.html) with a set of IMM engines RHS heads at 63 cc, TRW claims with a 63 cc head should be about 10-1 comp. which is still good for pump gas which is crutial in this build and something like a 280 duration cam. Now cams are the only thing i'm not positive about yet, i'm open to suggestions, i'd like to stay away from adjustable valvetrain if possible but lemme know what your thoughts are. Right now i have a holley strip dominator intake, i know its not the optimum intake for this build but it'll have to do till i can afford an air gap or something similar. I'm not positive on stall yet, something like 2500-2800?? and hopeing to run a 3.73 rear gear. What do ya guys think? what kind of power could i expect from a combo like that? Thanks in advance!!
 
I was told TRW isn't making pistons no more. I went with KB Hypers, price is better too. Check out Summit racing.

As for the T.C. just plan on doing it right and getting a tight 10 inch. Those $250 t.c. slip too much, imo. My tci Streetfight feels part throttle so much tighter than the old breakaway I had years ago.

280 cam would be fine with a 10 inch and 3.73 gears. Don't buy the pistons until the guy boring the motor says it needs only .020 over, my 340 had to go .040 over on a stock bore.
The strip intake is great and would work better than you might think. Some racers claim its a old wives tail that single plane intakes make less torque than dual plane intakes.\
 
With 10:1 your on the edge of cast iron pump gas but it's doable. Id recommend something with more overlap to bleed some of that compression off.
 
H116CP-20 pistons those are made by Seal Power and they are hyper.

Same piston Mopar used in the crate short blocks.
 
Most anything with 280 duration is gonna have too much lift for the stock rocker setup. you CAN do it, but it will never make the power it could with an adjustable valvetrain, plus your head work has to be SPOT on. I would recommend one of the smaller MP camshafts. There's one that's 450/455 lift that would set that engine on FIRE on the bottom end. Perfect for a street car and it has a little thump to it. then if you want something for a smoother idle you could always go with the original 340 cam. they have a power range from idle to 5800. Kinda hard to beat. I guess what I'm trying to get at is, with a street car you'll be happier with an under cammed engine than with an over cammed one. Most people tend to over cam stuff. they don't realize all thebenefits of a moderate to small hydraulic until it's too late. I'd much rather have tire shredding bottom end torque than a rumpity idle any day.
 
I think he is talking about 280 advertise duration which is going to be around 230 @.050 ...several cams like that have .480 lift total...with stock rockers...and the pushrod angle he is lucky he gets .450 lift at the valve.

I would also use a thicker head gasket and get compression down to 9.5...

am in the process of changing out engine in 73 duster..wont pass smog test in nevada
putting 360 with those same pistons....actually it is a mopar short block....pistons are down .040 in hole....took the MP 292/509 cam out...replaced with mild cam....421/449 lift from Erson...going order RHS heads for it...

get it smogged...and get Classic plates (no more smog test)...then chage to hydraulic roller since it is 91 roller block
 
I took for granted it was an advertised duration figure. The pushrod angle has little if no effect on valve lift. Have you ever measured it? I have and found it to be right on the money. I actually missed that his engine was a 10.1 motor. That's too much for an iron headed street engine. a TRUE blueprinted 9.1 almost is. You're going to need to do one of several things. Run a much larger camshaft with a good bit of overlap to bleed off cylindre pressure. Change your compression ratio. Or build the rest of the car to match the engine. Loose converter, short gears and the like. It won't be much of a street car anymore then. Good luck.
 
I've run a true 10-1 on 93 octane, no problems.

o the OE poster, a 280 advertised cam is, like said above, mostly found around 230 @ 050 with mostly a .480 lift. Stock rockers and pushrods should not be a problem. Pay attention to the pushrod pushing down on the lifter. You have some play there. It should not bottom out on the lifter. You should have depressed the lifter approx. .050 downwards. More or less is OK.

The strip dom is ok for use and a converter is best (IMO since I normaly hot rod the 4spd cars) done by a pro. A place like Dynamic converters. Theres a few places. But the stall sounds about right to me.
 
As for smog-safety checks, move to Michigan, the whole state has none. Can pretty much do whatever you like with your car / motor. As long as you can drive pass the police like everybody else.

Good luck on finding a job thou, ha ha
 
dodge freak said:
As for smog-safety checks, move to Michigan, the whole state has none. Can pretty much do whatever you like with your car / motor. As long as you can drive pass the police like everybody else.

Good luck on finding a job thou, ha ha
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exactly..no smog check needed went no one has a job....
 
Way back like 25 year ago we had them by Detroit, the greater Detroit area. Was for only car and trucks 12 years old or less. Was pretty much a joke cause like every auto shop in town did them and you could even use a different car. I recall taking all 3 forms with me and having a guy do all 3 with the same car, ha ha.

The whole thing is a joke when you look what big businesses are getting away with. Look at all the ozone / smog that big oil spill is doing. Here we used to be told not to fill up the gas tanks during hot days to reduce smog. Oh yeah, BP money will solve everything.

The main reason places have smog test is for the rich peoples cars won't get its doors blown off by a $25,000 hot rod car.

We want safety, lets have roll bars in cars and wear helmets and thrown those air bags in the trash. Oh yeah, then the car can ram stuff and keep going.

Seat belts are for in case of a fatal crash the driver can not claim the dead person was really driving, lol.

Sorry for the rant!
 
rumblefish360 said:
I've run a true 10-1 on 93 octane, no problems.

o the OE poster, a 280 advertised cam is, like said above, mostly found around 230 @ 050 with mostly a .480 lift. Stock rockers and pushrods should not be a problem. Pay attention to the pushrod pushing down on the lifter. You have some play there. It should not bottom out on the lifter. You should have depressed the lifter approx. .050 downwards. More or less is OK.

The strip dom is ok for use and a converter is best (IMO since I normaly hot rod the 4spd cars) done by a pro. A place like Dynamic converters. Theres a few places. But the stall sounds about right to me.
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Not a blueprinted 10 to 1 you haven't. not with iron heads. Ain't no way no how. I don't know why people insist they have. It's just not possible. Maybe if you cranked the initial timing back so far it ran like crap. Or unless you had it so ridiculously overcammed it bled off half the cylinder pressure. If an iron head engine runs with no detonation on 93 octane with ALL the timing it can stand, it's got no more than 9.5 to 1 at the absolute most. Whether you heard it or not, if you had a true blueprinted 10 to 1 with iron heads and had all the timing it needed it was detonating. All you have to do is look in any Chilton manual or similar and you'll see even at 9.2 to 1 premium fuel was required. Not recommended, required. ....and that was back 35 years ago, when gas had some lead content left and was pretty good. You're dreamin if you think you can run that high a compression on today's pump gas with no detonation. Sorry friend, it's not possible.
 
ok thanks guys for the opinions, i really didn't know that iron heads made that much of a differance, i'll definatly have to bring the compression down a little, this is a street motor that needs to run on pump gas. and if i do that it would be a good idea to have a bit smaller of a cam correct? and yes i was refering to advertised duration, sorry for not being clear. no problem with smog crap up here in the great white north lol
 
StrokerScamp said:
Not a blueprinted 10 to 1 you haven't. not with iron heads. Ain't no way no how. I don't know why people insist they have. It's just not possible. Maybe if you cranked the initial timing back so far it ran like crap. Or unless you had it so ridiculously overcammed it bled off half the cylinder pressure. If an iron head engine runs with no detonation on 93 octane with ALL the timing it can stand, it's got no more than 9.5 to 1 at the absolute most. Whether you heard it or not, if you had a true blueprinted 10 to 1 with iron heads and had all the timing it needed it was detonating. All you have to do is look in any Chilton manual or similar and you'll see even at 9.2 to 1 premium fuel was required. Not recommended, required. ....and that was back 35 years ago, when gas had some lead content left and was pretty good. You're dreamin if you think you can run that high a compression on today's pump gas with no detonation. Sorry friend, it's not possible.
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I'm planning a 360 Magnum build with iron heads and ~10.5:1 compression with a 213/220* @ .050" cam. Another member 'dgc333' has a 10.6:1 360 Magnum also with iron heads and he claims it runs with no detonation on 89 octane gas with near-optimal ignition advance and a 268* adv. duration cam. The reason this is possible is quench, which comes into effect when there is a sizable flat surface in the chamber for the piston face to come close to at TDC. It causes the A/F mixture to rapidly "push" out from in between the two before combustion; this rapid movement makes it more difficult for detonation to occur as it simultaneously cools the mixture and vaporizes any liquid gas droplets. The turbulence also reduces the likelihood of hot spots in the chamber which is another source of detonation.

I can't physically prove it but there is a member from another forum (allpar.com) who has been porting heads and building engines for decades, and he claims to have built several (not just one) street engines with upwards of 11:1 compression that ran with no detonation on regular pump gas (87 octane?). His 'secret' was to run a good closed-chamber head and radius (not just smooth) all of the edges around the chamber and on the piston face. BTW this is not easy or quick to do so I'm not saying it's a 'magic bullet.'

I agree about the cam though, the OP would probably be satisfied using something with less duration but good lift. My plan for my 360 is to re-use the Lunati Voodoo 256/262 out of my 318 with 1.6:1 rockers. This should give .484/.507" lift at the valves but with duration @ .050" only being 213/220* it should have lots of torque everywhere. Later when I swap in a 4-speed I'll upgrade to a hot solid cam or something...:snakeman:
 
ok, thanks again for the tips guys, this is all very useful, what cam would some of you suggest, i know theres already been a couple thrown out there but i'd like to hear a few different opinions. Thanks again guys!!
 
When I say "no way no how" I mean strictly from a layman's approach. Not getting fancy with radiusing edges and so forth. I know it CAN be done, but I'm speaking merely from a COMPRESSION standpoint. Anything that came from the factory with over 9.2 to 1 would spark knock on today's fuel with no special machine work. Most novices either don't have the skills or cannot afford to pay for such work. It's not cheap and if you take a grinder to your own heads, you might end up wishing you hadn't. Now, I got this thread a little off track. Sorry bout that. Lets try to continue helping the op. I don't think battin this back and forth is doin that. LOL
 
74scamp360 said:
ok, thanks again for the tips guys, this is all very useful, what cam would some of you suggest, i know theres already been a couple thrown out there but i'd like to hear a few different opinions. Thanks again guys!!
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Crane made an awesome camshaft that specs out at .464-.494 lift and 222- 234 duration at .050" ground on 114 lobe centers. works very well. Only problem is, I don't know if S&S Cycles has everything available yet. They bought Crane out a while back.
 
StrokerScamp said:
Not a blueprinted 10 to 1 you haven't. not with iron heads. Ain't no way no how. I don't know why people insist they have. It's just not possible.
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YES! I have. YES! it is possible.


Maybe if you cranked the initial timing back so far it ran like crap. Or unless you had it so ridiculously overcammed it bled off half the cylinder pressure.
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Neither



All you have to do is look in any Chilton manual or similar and you'll see even at 9.2 to 1 premium fuel was required. Not recommended, required. ....and that was back 35 years ago, when gas had some lead content left and was pretty good.
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LOL, OMG, your useing a chiltons to argue your point, ROFLMAO!!!!!!!!!
Bwa ha ha ha ha ha ha


You're dreamin if you think you can run that high a compression on today's pump gas with no detonation. Sorry friend, it's not possible.
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I did it everyday in my daily driver. 4 seasons long, 3 years running, everyday.
Also,, every high performance car these days run more compresion and hotter cams than what was listed here.

When I say "no way no how" I mean strictly from a layman's approach. Not getting fancy with radiusing edges and so forth. I know it CAN be done, but I'm speaking merely from a COMPRESSION standpoint.
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Back peddling allready? You started this "Battle"
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No back peddelin. I was just talking about stock unmodified engine parts. I should have made that clear.
 
someone also mentioned using a keith black piston, with those heads that i listed above which set of pitons could i use and still have a reasonable compression ratio? Like i have said this will be a mostly street engine with a couple fun track days a season, but on the other hand me being young it needs to be able to scare all the stupid ricer kids that think they're so much better. can't be losing to any ricers lol. thanks again guys!
 
for the 107's i typed in the 67 cc head volume and it have me about 10.3-1 which if thats accurate i think may be a little to much for me. Is that calculator accurate or is there a better or more accurate way to calculate a rough compression ratio. i guess it all depends on how thick of head gasket you end up using as well correct? And any more cam suggestions are welcome. has anyone used a mopar purple shaft? i've never heard good or bad things about them and was wondering what people who have used them have thought, can i get away with a mopar shaft or should i be putting up a little more cash for a comp cam? let me know what your thoughts are i'm still in the planning stages and really wanna get this engine done right the first time.
 
The kb107's with a standard (Mostly seen since there all open chambers) 360 head of approx. 72 cc's and a .039 gasket should clock in at approx. 9.8-1. Fel-Pro also makes a .054 thick gasket that will edge the ratio down just a hair to about a 9.5-1 ratio which is excellent for pump gas and power. At this ratio, you can also run a street cam, (Considered a small cam) something like what you were thinking about earlier. That 280 duration cam, the stall on the converter and gears you mentioned will be a real nice streetable and potent engine.
 
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