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Can a 357 with 270 duration (580 lift) solid lifter, 850cfm IDLE?

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Hal's64Malibu

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Discussion starter · #1 ·
Just bought a '67 with a 357, 270 duration solid lifter with a 850 mechanical carb. Do you think this thing can idle? Certainly doesn't seem to want to go into a lope. Best I can do in neutral is a bad 1.5k idle that dies. This was an x-drag car (T400 with 4.53 rearend). Doesn't seem to be a blown head gasket (no water oil/oil water).

Hal
 
#5 ·
You didn't answer so I'll take a shot.
If that 270 is advertized ,then your only in the 22x range @ .050"
If it's 270 @ .050" then I'd suspect timing's off at the cam or distributor.
For the heck of it ,make sure # 5 & #7 plug wires aren't crossed.
Next would be a vacuum leak.
 
Discussion starter · #6 ·
Sorry, late after the game. Yes, at .50 it is 270. I think it's a 3500 stall. Hard to tell what the advance is because it dies at 700rpm but maybe 20 (its around 35 at 1500 or else it wants to die). Not vacuum dist. Cam is set right. Not sure what you mean by timing off at distributor? 5to5 7to7 (not an odd cam). Would a vacuum leak be a problem with a mechanical distributor (or whatever it is called)?

Hal
 
#7 ·
I have seen 253@ .050" and 9:1 compression 350 not want to idle.

Only had 5" of vacuum at 1100-1200 rpm.

So if vacuum is really low ..you need to make sure the Power valve is not coming in ..

low compression sucks with big cams..
Some carb boosters are very touchy(annular) and a shaking idle will actually make the boosters dribble fuel at idle.(sometimes)..this will make it want to die ,,like flooding it...You will always be clearing it's throat before you drive off from an idle.
 
#8 ·
A cam with 270@.050 will not idle at 700rpms. You will need to be in the 1200-1500rpm in park and 1000-1100 in gear. You will need more than a 3000 stall to make it work but it should idle ok at 1000 rpms minimum. You need to get the specs of the engine. Doesnt sound like a "ex-drag car", sounds like a current drag car that someone thought they could drive on the street.
 
Discussion starter · #10 ·
Has a Brodix tall intake with track 1 heads, do those kill vacuum at idle? Engine is very crisp, no clearing needed. 3500 stall. I'll plug the carb vacuum booster line and see if that helps (maybe a leak at booster?). Yes, still all drag but with tags, I just thought it would work better than this.
 
#14 ·
I'd start by locking out the timing. Set it at 34* and see how she starts and runs. Once timing is set, tune carb for best vacuum reading and make sure, as has been mentioned, the power valve is rated lower than the vacuum reading you're getting. With a cam that rowdy on the street, might make sense to plug the pv and jet it up, although that's usually a crutch for another unresolved issue.


Sent from my iPhone using Autoguide
 
#15 ·
Hal
Bottom line here
All the tuning in the world is not going to make a 350 inch engine idle at 700rpm with a cam that is 270° @ .050
It really is that simple & changing timing, power valves,,,,
tuning under a full moon or any other trick is not going to make it happen

The best you can do is lock the timing & set it where it is happy or think about a better cam choice
Also, a 3500 stall converter is a horrible choice for this combo
5000-5500 would be a lot closer & still low with that cam

Consider that most reasonably serious street strip 550+ inch engines use a cam in the area of what you have duration wise with most being less & you should start to understand why what you are doing is not going to happen ;)
 
Discussion starter · #16 ·
Thanks for the speed shop confirm on this Mike. I certainly didn't think it would but didnt want to give up without knowing. The cam is bigger than anything i could find on Summit and is a custom Blackstone grind.

Another problem with it is overheating. Good size be cool rad but fans (2) with only 9 amp each in push pull config may be small. This car was probably only set up drag so cooling not a big issue but i want to get that straightened out next.

Hal
 
#17 ·
Mike Lewis hit it with the converter, it should be 5000 or more. And like he said, my 540 in the Chevelle idles at 15-1600 and is 275/287 @.050. With 13.5-1 compression too.
 
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#18 ·
If your radiator is big enough
Black magic PN FLX188 at summit $284
4" thick
18a
3300 cfm
That will cool about anything down in a hurry
Get a high amp alt

Ditching my 2000 cfm 20a spal for something similar
Dimensions are too big for a stock type rad but have different models



Or use a black nylone flexalite fan with the shroud that will do the trick then put a higher temp fan switch on for your exiting electrics as a backup just in case youre stuck in traffic. Those fans are super light, cheap and work killer...fairly quiet too. Ive never busted one, circle track guys love em
 
Discussion starter · #20 · (Edited)
It's a 4-core Be Cool so I think it's big enough. I didn't want to start it and drive to warm it up (neighbors). I ran just the front fan in the video. I think it's because the shroud is just a circle around the blade and doesn't block the rest off. You can feel a lot of the front fan air that goes around the radiator instead of through it. Maybe I can get sheet metal enclosure for the inside fan?

http://s143.photobucket.com/albums/r156/hfish1212/?action=view&current=DSCF7272.mp4

Hal
 
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Hal's64Malibu
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