|08-05-2010 12:46 PM|
Everywhere you read they say it is bad for torque to run big cc heads with a mild cam. And the dynos show the same thing.
However, I had a different experience recently that makes me not care so much about that.
a friend of mine build a simple 350 (9.3:1 cr) with a th350, 2.87 rear gear, and a stock stall. Has a little 260H compcam in it. He had old fuelie 2.02 double hump heads with 64cc chambers and 165cc intake ports. The heads kept blowing exhaust header gaskets so he tried a set of my 200cc dart iron eagles. And we felt no performance difference in the low rpms and maybe felt a little stronger on the top end. Really hard to tell any difference at all. Surely wasn't a super noticeable difference as you would predict from reading engine tech articles.
Sure, I try to match my engine components according to the "standard" but I don't think I will worry too much if the heads are a little too big for the cam. Especially since your engine is a 383 with a 3.42 gear.
check out his web site. http://www.ryanscarpage.50megs.com/combos2.html
combo 11 is about what you have. also notice combo 12 which is a 350 with biggish 195cc heads and also has a cam about the same size as your.
|08-05-2010 09:10 AM|
Your engine is made of a lot of mis-matched parts, but it will run. A lot of people think that if you pick a low RPM cam and high RPM heads you get the best of both world- in fact you get the worst of both worlds.
For now it is what it is, but you need to decide what you want out of the engine and then modify it to fit that goal. cobbling a bunch of cheap parts together will get a car moving but it will be far from optimal.
|08-03-2010 03:25 PM|
|havin_a_ball||except the stall converter seems to be an easy add on, that you suggested, so I will add that & the Intake & carb, but hold off on the cam replacement|
|08-03-2010 03:23 PM|
|08-03-2010 01:50 PM|
|454C10||My advice is, if you are happy the way it runs now then don't mess with it.|
|08-03-2010 09:40 AM|
The "new" 1973 z28 I got to put the engine in has a 3.73 gear ratio. I called Lunati this morning to try & decide whether it would be worth it to buy another cam and lifters & pay to have it professionally changed.
I was given this cam as a better one for this exact setup
Lunati Voodoo Hydraulic Flat Tappet, Advertised Duration 262/268, Lift .468/.489, Chevy, Small Block,
so I think I would be looking at $200 in parts + the install.
I'm not sure if the power increase would be worth the change, when I could get the Holley Carb & Intake that was mentioned for the same price, not to mention the engine runs well now and I don't want to jinx it, but then again, after all this, why settle for mediocre?
I ended up in a virtual dyno software thread here that I was going to use to determine the power gain from changing cams, but readers said the software was crap, so I didn't get it.
What I would LIKE to do is put a tremec 6 spd manual & supercharger in, but I think it would be money down a pit on the 73 camaro, b/c I would like to sell it eventually (in theory)
|08-03-2010 09:22 AM|
The cam seems to be a little on the lazy side. with 284 advertised and only 218 at 0.050". The lift does match the duration at 0.050". The good thing is the cam will likely live a long life due to it's soft ramps.
should run a 2000 to 2200 rpm stall with a 3.42 gear.
|08-02-2010 11:26 PM|
I got my engine back to my house & took it out of the car & found out what type of cam is actually in the engine.
Camshaft, Hydraulic Flat Tappet, Advertised Duration 284/284, Lift .458/.458 Lobe Separation (degrees) 110
On one hand, it is a lot closer to what i need in the car, on the other hand, I was told it was a Voodoo Hydraulic Roller Cam, so I paid $100 bucks for it, but I think that was all a lie and there was never any cam change.
Is the cam in there good for the engine, or just blah?
I THINK that with an rpm range starting at 1,500 I don't need to do anything to my 350TH like add a stall converter, so that may be good.
I had the engine made for a 78 el camino, but realized I would not be able to get that $$ back out of the car, so I bought a 1980 z28 with T-Tops that had a good running 305 sbc with a 350TH, that I could actually make sure worked, as it was in the car, and put that in the El Camino, which brought my costs back in line with what the car is worth. provided that I can sell the camaro for $800 which would mean I got the El Camino an engine & tranny for $500 installed, that I know works well.
But if I wanted to get the $6k I have in my engine back out someday, I knew I needed to put it in a more valuable car, so I bought a 1973 z28 which was in "B" shape, but had no motor or trans.
This was my first venture into this stuff & I never expected all this, but it is fun learning, as long as I don't lose money in the end, and get to drive fun cars.
So, my "custom" 388 stroker is out of the car now, if there is anything I need to do to it, now is the time, if I need a stall converter, new cam, or bigger than stock oil pan. I will go ahead and get the Holley 750 carb and RPM manifold, as suggested above.
I had the engine in the 80 camaro for awhile to test and break it in and it runs extremely well from an idle, starting, sound, and burning rubber standpoint. I didn't have any guages hooked up, so I don't know the speeds or oil pressure, but it was not running hot & would get rubber starting and going into second.
I felt like there was too long a time from when my foot hit the gas to when the car took off, but I think the carb & intake change might fix that.
Anyway, that's it - Thanks for the advice. I guess if anyone wants to buy a 1980 z28 t-top roller for $800 contact me
ps - the vin & cowl were checked on all the cars & are both z/28s
|06-30-2010 10:10 AM|
Thank you SOO much!!!
This would have been a nightmare if the engine got put in with the wrong cam
|06-30-2010 09:20 AM|
|454C10||sure, those cams will have only a slight lopy, very slight. vacuum should be good, 16 to 17 inhg depending which cam you choose from that group.|
|06-30-2010 08:56 AM|
You think I can still run air & power brakes?
|06-30-2010 08:51 AM|
these would work.
hard to find a single pattern cam these days.
|06-30-2010 08:37 AM|
you will have about 9.5:1 cr.
get a mild cam to match the compression, gear, and stall.
a cam with about 260 degrees duration (seat to seat) will work well.
I would get a cam with 110 lsa, 260 degrees on the intake and 260 degrees on the exhaust. no need for more duration on the exhaust.
|06-30-2010 08:35 AM|
He's fixing the issue, but I forsee another issue with the wrong cam, so I want to head this one off & get my car outta there & back to my house after he puts the motor back in. I don't want him to put the motor back in the car until I have the best cam for the rest of the engine, if that makes sense
|06-30-2010 08:26 AM|
Here’s the specs on the pistons:
Keith Black/KB Pistons KB135-060
Pistons, Hypereutectic, Dish, 4.060 in. Bore, 5/64 in., 5/64 in., 3/16 in
ore (in) 4.060 in.
Bore (mm) 103.124mm
Piston Style Dish, with two valve reliefs
Piston Material Hypereutectic aluminum
Compression Distance (in) 1.433 in.
Piston Head Volume (cc) +18.00cc
Wrist Pin Style Press-fit or floating
Pin Diameter (in) 0.927 in.
Piston Ring Thickness 5/64 in. x 5/64 in. x 3/16 in.
Quantity Sold as a set of 8.
Notes D shaped recess. Piston weight 500g, pin weight 145g.
Here are the numbers on the heads
Intake Flow Exhaust Flow
Straight plug 64cc combustion cambers
Valve springs installed @ 1.80 with 140# closed pressure
Springs good to 600 lift
These heads are best suited for engines in the 350-550hp range using solid flat tappet or hydraulic roller lifters.
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