I am down to selecting the best cam for my 63 engine rebuild.(Driver,using flat top pistons for lower C.I.) So which cam should I select:The 097 Duntov, the 30/30 or the LT1 ?
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Re: FI.Cam
Don't use the 30-30 cam. (personal opinion)
Needs higher compression ratio.
Has little low end torque.
Comes on strong about 4000 RPM.
The LT1 cam has more low end torque (is more driveable)and gives up little in high end horsepower.
I drove an FI car with the 30-30 cam for a couple of years and took it out.
Yes, it ran very well when I stood on it but it was a pain to "just drive normal."
Verle -
Re: FI.Cam
I was searching the archives last nite and read to be very careful on cam selection on fuel injection motors due to cam overlap and vacuum loss to the injection unit. There was a lot of info in the archives on this subject!Dino LannoComment
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Often overlooked...
...is using Roads lifters. I built some 350's for a couple of twin-engine offshore boats a while back, and boats are kinda demanding. If you want to cruise at 60-70 mph on water, your gonna be at WOT much of the time, which calls for a pretty hot cam (and fuelie heads, etc). BUT- hot cams idle lousy, which means to get a safe, steady idle you have to bump up to a higher idle- bad idea if you don't want to slam into the dock. The Roads lifter is designed to "leak down" at low engine speeds, which meant I could get a "3/4" Crane cam to idle at 400rpm. They work up to full profile at 2500-3000. And if you don't want to use "flat" lifters, Roads will convert your roller lifters for $60. The only drawback I can see is they have a slight "tic", similar to well-adjusted solids. I have since used these in cars, with equally satisfying results.Comment
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Re: Often overlooked...
The Viper has used Rhoads roller lifters since '96 - calms down the idle with the fairly radical cam so it passes emissions, and they do make a little bit of (nice) noise, although it's masked by the tick-tick-tick of the top-mounted injectors. They work.Comment
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Re: FI.Cam
The LT-1 cam makes better torque bandwidth than any other SHP cam, and I've not found an aftermarket cam that is better. Chevrolet didn't sit on their hands for 15 years after the Duntov cam was released. They did a lot of R&D for the LT-1 engine, and they new the 30-30 was not the hot ticket - too much of a torque killer.
Top end power is about the same as the 30-30, but the LT-1 cam has a little more rolloff beyond 6000. Average torque/power from 2500-6500 to the rev limit beats any other SHP cam, and I highly recommend it for all solid lifter rebuilds and solid lifter conversions.
DukeComment
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Re: FI.Cam
I have found that the 350 horse 327 cam known as a 3151 is great with flat top pistons.. I have put over 70k miles on a 63 with FI and it makes good power,good gas mileage(20mpg) and is very low maintainance as you don't have to adjust the lifters. My 71 has a fairly radical cam(too much for AC) and I tamed it down with Rhoades lifters and I think a lot of them. PaulComment
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Rainer: Don't You Remember What Bill Clupper......
said about the vac signal generated by the Duntov cam re: your post below (SB Fuelie Engine Crank, of Sat8/23) ? Please let us know, first of all, whether or not you canned the engine builder who was going to try to install a large journal 350 crank into your 870 block. We'll talk further, from there.
Joe
PS: The email you sent me a few days ago, was flagged by my antivirus program as being infected. Please check it.Comment
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Re: Rainer: Don't You Remember What Bill Clupper..
In reference to my engine builder's intent to use a 350 crank: He was going to turn the journals down to the correct dia,and use pistons with the wrist pin closer to the dome. He can reharden the journals. He claims that he has build several engines with this crank with good results. He claims that the engine would produce around 400 HP. I guess, he is a race engine builder, but has rebuild many engines for corvette restorers before.
I have decided, to go with the original crank and flattop pistons. It will cost me a new set of pistons, because I had originally agreed with his suggestions. But I got cold feet, even though, he assured me, that he would guaranty the rebuild.
I guess, race engine builder always want to to increase HP, which I don't.
So, its back to 327 forged cam with flat top pistons and an LT1 cam.
Rainer
Joe, I send the E-mail thru this website, while signed on at Ford Motor Co. I will run an antivirus software.
ThanksComment
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Re: Rainer: Don't You Remember What Bill Clupper..
Rainer:
I am glad that you have decided to use an original 327, forged steel crank. I still think that you can safely use domed pistons, but I am not certain of the quality of the fuel in Germany. The LT 1 camshaft is probably the best bang for the buck, so long as originality is not your top priority. As far as Bill Clupper's input, in reference to vacuum signal on the Duntov cam, I can say for certain that the LT1 cam will give vacuum characteristics more closely matched to the original "Duntov", than will the "30-30".
JoeComment
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Re: Rainer: Don't You Remember What Bill Clupper..
The reason Chevrolet increased the journal diameters on the 350 crank was to restore lost overlap from the increased throw radius, not because the bearings were insufficient size to carry the load.
There may be many ground down 350 cranks in 327 blocks that are running okay, and maybe some have failed. Who knows, but in the long run I would trust the decision of those engineers 35 years ago more than the local machine shop.
DukeComment
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