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Old 05-29-2013, 03:15 PM
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Quote:
Originally Posted by ap72 View Post
For a more aggressive sound run 2.5" dual pipes into thrush welded mufflers.

For the cam out of the 3 you picked I would go with the crower cam and 1.6 rockers.

Or call lunati for the cam I spec'ed and run 1.5 rockers.
Yeah I'll give Lunati a call and see what kinda price they are running for changing up the LSA like that. And I am running dual 2.5" pipes, y pipe, and into a 3" muffler... Just went back to my old relieable Hooker Aerochamber after the entire case on the front side of my Thrush slit apart... Sounded good but sure didn't last long. Love the Aerochambers though.

Quote:
Originally Posted by steeny View Post
RyanR, If I may..the 750 is too much that you will never use if it is to be driven as you say. Not that the carb won't work..you are going to have to work at it to make it right for the app. If you don't feel comfortable diving deeper into carburetion other than a jet change and a power valve, get a 600-650.
It's not that I'm scared of diving into a carb and picking up the learning curve, it's just that I already have one handy.. May just sale them and pick up a Demon Slayer

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  #17 (permalink)  
Old 05-29-2013, 03:28 PM
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Originally Posted by RyanR View Post
but I'd still like a cam to sound pretty serious but not so much that it won't hardly idle on its own, ill matched to my setup, and unpractical.
It's very simple, if you want to run more cam, then run more gear. Step up to 6.17's front and rear and build the motor with more static compression ratio and more cam. With your current 4.56 gears, more cam will make a dog of the truck and you'll hate it.

I'll stick with my first recommendation, 4.56:1 gears, 24cc pistons, 64cc heads, 9.00:1 static compression ratio and the Crane cam I referenced.

In the end, do what you think will make you happy.
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Old 05-29-2013, 03:44 PM
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RyanR, no matter what carb you pick, the comp. ratio or cam, this build like most others that want grunt at the low end, it will probably ask for a fuel curve that comes on early, not MORE just the normal volume shifted down in the curve and RPM range. Don't mistake this for more volume (richer) of fuel just were the volume comes in. Again my 2 cents on this.
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Old 05-29-2013, 03:59 PM
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most box stock carbs won't have a problem with this, maybe change the PV down a hair in a holley, larger PVCR's and an edelbrock will want lighter springs and a thinner rod, nothing too extreme, you'll have pretty good vacuum with the right timing curve.
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Old 05-29-2013, 04:15 PM
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ap72, the box stock 600-650 yes.....the 750 more into the emulsion holes sizing and main bleeds. Not more, just when the boosters become active but not the power circuit, that's just a little later in the curve.
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Old 05-29-2013, 05:40 PM
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Just to be different,I would use 9:1 CR with vortec heads, 216/222 @ 050 and 500 lift,and the 750 holley.small diameter long tube headers. LSA and ICL,I would really think hard on this one depending on intake closing time.
Tech is the math wiz here,I would start my figures at 106/110 and compare that to 108/108
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Old 05-29-2013, 07:02 PM
How fast is fast enough?
 
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Lets see a air dyno shoot out, the lunati cam I suggested vs one vinnie suggests, adjust advance for best numbers.

And 9.5 is safe but 9:1 isn't going to hurt a lot maybe lose 5-10 ftlb, not much.
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Old 05-30-2013, 07:49 AM
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Quote:
Originally Posted by ap72 View Post
Lets see a air dyno shoot out, the lunati cam I suggested vs one vinnie suggests, adjust advance for best numbers.

And 9.5 is safe but 9:1 isn't going to hurt a lot maybe lose 5-10 ftlb, not much.
Boy this is turning into a good thread

Another noob question.... but what's a "air dyno"? Something like desktop dyno or ? And if so yeah y'all plug in the cams and compare please. Throw in my Crower as well with 9.5 cr please
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Old 05-30-2013, 05:10 PM
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Well fellas I hope I haven't wasted ur time... looks like I'm picking up a freshly built 400 with a Scat rotating assembly. Complete oil pan to carb. Its a touch high on cr at 10.3-1 72 or 73 cc heads but I'm gonna try to lower some if I need to and it already has an rv cam in it. Good price. I may go ahead and change cams just so I'll know whats it it. He thinks its a 278 comp rv cam but wasn't 100%. Any thoughts fellas?
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Old 05-30-2013, 09:30 PM
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10.3:1 Cr with cast iron or aluminum heads? I hope you are not buying a "deal" hoping it will fit what you need?
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Old 05-30-2013, 09:44 PM
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Quote:
Originally Posted by RyanR View Post
but I'm gonna try to lower some if I need to and it already has an rv cam in it.
And pray tell, how would you lower the static compression ratio if you need to? Please don't say with a thicker head gasket!!!!!
Also, you don't need to refer to a 278 degree cam as an "RV" cam, cause it ain't. An "RV" type cam is one that is just one or two steps over stock, just enough to increase the bottom end torque a little so that towing or pulling hills comes easier.
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Old 05-30-2013, 09:54 PM
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100% sure

Quote:
Originally Posted by RyanR View Post
Well fellas I hope I haven't wasted ur time... looks like I'm picking up a freshly built 400 with a Scat rotating assembly. Complete oil pan to carb. Its a touch high on cr at 10.3-1 72 or 73 cc heads but I'm gonna try to lower some if I need to and it already has an rv cam in it. Good price. I may go ahead and change cams just so I'll know whats it it. He thinks its a 278 comp rv cam but wasn't 100%. Any thoughts fellas?
someone offers an engine and isnt 100% sure whats in it? any alarms going off?

I agree with tech and funny names for cams,,
when I was new to engines I was told an R.V. cam was for enhance performance for "recreational vehicles" like motor homes,,, in the 70s cam timing was late and engines were getting lazy,so the "rv" cams were close to factory duration with the ICL advanced and a little more lift for breathing.
now RV seems to be slang for mild flat tappet hydraulic cams for moderate powered daily drivers
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Old 05-31-2013, 11:59 AM
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Calm down fellas. Its a good enough deal that if I absolutely need to, I'll buy new pistons, rebalance, and put it back together. As for the cam, thats what he referred to it as... guess mild street cam would be better terminology. I'll get the number off it when its at the house. And as to the unknowns of the engine, story behind it is a friend of his built it for a Nova project he was working on.... came on hard times and had to part with everything.. Seller bought it from him more as a courtesy gesture thinking he would start a project and possibly use it.... says he doesn't have time for it and just wants to cut his loses and see it actually get used. Super nice guy. He made me a fair enough deal that I can make the changes where I need to and completely make it work for my truck, even if it needs a full rebuild. Now calm down guys, dont blow a gasket lol... its gonna work out alright. And no I'm not just sticking it in my truck. Its going in my work shop on the engine stand and I'm gonna thoughly check it out and go from there.

And it has cast iron heads on it. Originally had a set of Brodix on it but original seller sold them to help pay bills... so its back to the stock cast iron heads.
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