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Topic Review (Newest First)
02-13-2013 12:02 PM
Choctaw Bob I had the same problem with my T-Bucket that I bought. It has 2 new Edelbrocks on a tunnel ram on a BBC.
You can download a carb tuning manual from Edelbrock.
That's a pretty big cam for the rest of your combonation as others have brought up. I think I would start with a vacuum gage and check to see how much vacuum the engine is pulling. Both your carb and distributor works on vacuum and the big cam doesn't put out much. As those carbs come from the box they need around 12 inches of vacuum to seat the rods against the springs. If vacuum is bouncing around at idle, you should be getting over rich mixture at idle. Edelbrock sells spring kits to adjust these.
Others have suggested changing to a Holley or Demon type carb. They still have power valve issues but they are easier for some to deal with. The Edelbrock can be tuned to be reliable but it may take a cam change to make it work. This might be the best solution. Something like the old 350 HP 327 has a bit of a thump to it and still is a lot easier to live with on the street.
I had to change the cam on mine to make it livable on the street.
02-09-2013 07:58 PM
F-BIRD'88 read my post #3 here
http://www.hotrodders.com/forum/init...ng-225000.html
02-09-2013 07:57 PM
Mrziggy4 Ok thank you
02-09-2013 07:54 PM
F-BIRD'88 a circle is 360 degrees. 36deg is 1/10th that.
therefore 36deg from TDC on the balancer is 1/10th then way around the circumfrence... figure it out.
grade 8 math... google it.
02-09-2013 07:52 PM
F-BIRD'88
Quote:
Originally Posted by Mrziggy4 View Post
The distributor is a gm hei.

So if I mark it at 36 degrees btdc what do I use as a guide to know where I'm putting my mark? Would it be the marking tabs?

Basically would my line be at 36 degrees according to what the tab show 36 to be?

I just to a look at it and the tab only goes up to 16 degrees? So how am I'm checking for 36.
Dude get a clue mark the balancer at 36deg or buy and install a timing tape.

GM HEI


How many million more times do I have to repost this picture
02-09-2013 07:36 PM
Mrziggy4 The distributor is a gm hei.

So if I mark it at 36 degrees btdc what do I use as a guide to know where I'm putting my mark? Would it be the marking tabs?

Basically would my line be at 36 degrees according to what the tab show 36 to be?

I just to a look at it and the tab only goes up to 16 degrees? So how am I'm checking for 36.
02-09-2013 07:17 PM
F-BIRD'88 when you correct the balancer for true TDC using a piston stop you can also mark the balance at 36deg BTDC
that is exactly 1/10th the way around the balancer from TDC.

what distributor? MSD read the instructins it easy.
GM HEI is easy too. but differnt

some advance timing lights get all wacked by a MSD spark box.
marking the balancer at 36deg allows you to verify the advance light is accurate.
if its a old stock balancer a slipped outer ring is suspect. if thats the case replace it as a slipped outer ring is soon going to come
unglued and it ain't pretty.

Aftermarket timing tabs are always out f wack. There are three different balancers/timing tab locations for TDC.
and six different way you can mismatch that.

You cannot set the timing or tune untill the TDC pointer is accurate.

A 750 carb always makes more ower than a 600. but any all carbs will need spcific setup. Once set up the 600 will run fine.
02-09-2013 07:12 PM
Mrziggy4 Thanks f-bird I'm gonna try that tomorrow. Just curious I just picked up a timing light that is adjustable in the back. Should I have it set at 0?

How do you lock out the timing curve?

The mechanic that checked it out remarked the balancer not sure what the reason was. I'm going to determin TDC when I do should the mark be at 0?

Sorry if these are dumb questions I've never done this before and am learning as I go.

Thank you
02-09-2013 05:07 PM
F-BIRD'88 Mr Xiggy.. temperairily lock out the timing curve. Set the locked fixed timing at 36deg BTDC.

Now reset the carb and . Now you can fine tune from there.
This may not be the idle spark advance you end up with but it is the place to start at.
locked out at 36deg BTDC is not too much. you can fool around with it from there.

26++++ deg base at idle for a cam like that. 36 fixed /locked is not too much for a cam like that.
The timing must not drop off when you idle in gear.

if you have a auto trans and this is the cam you got, you will find the locked out mechanical timing very effective.
Wether you use the carb you got or a holley or.... will not change this.

functional vacuum advance can be retained but will need to be set up. Use ported vacuum.
02-09-2013 04:30 PM
Mrziggy4 Thanks again everyone, I'm gonna look into getting a new Holley carb to replace the once I have then ill check on the timing and the other things you guys have recommended.

I'll post an update when I get the new carb

Thanks
02-09-2013 12:04 PM
vinniekq2 750 cfm is a good size carb for mild to moderate 350s
02-09-2013 06:53 AM
Mrziggy4 Thanks for letting me know about the carb. The original builder had a Holley carb i think a 750 CFM. Then the previous owner bought this carb, I thought from what I had read that the carb was not big enough but wasn't sure. I might just look into buying a bigger Holley carb before I mess with anything else.

Would a 750 CFM be good enough?
02-09-2013 05:16 AM
75gmck25 Edelbrock makes several 1400 series carbs, but the most common is the 1406, which is set lean to get good fuel mileage. It would run with your engine, but it would not be a good match for this cam.

Also, if the owner used a HP fuel pump, verify the fuel pressure stays within Edelbrock's recommendations (5 psi?). The 1400 series does not run right if the fuel pressure is too high.

Its quite easy to swap rods, jets and springs on a 1406 to tune it to run better for high performance. However, without an AFR and some other tools to see the effect of your changes it will mean a lot of experimentation before you get it right.

Instead of tuning the current carb it may be simpler in the long run to swap it out with a Holley or one of the other Edelbrock carbs that is a better match to the rest of the engine.

Bruce
02-08-2013 09:30 PM
cadillacdave1 I may be incorrect but the Edelbrock 600 carb is for stock to mildly modified motors. A sbc with a 298* duration cam is not mildly modified. This carb is not designed to work well with this type of cam and can be very difficult to tune. You may need a larger holley style carb with mechanical secondaries for this set up.
02-08-2013 08:29 PM
RWENUTS One glaring thing in your video that's not a good idea is the rubber fuel line. SEt up a metal tubing line.
Unlees of course you like massive engine fires. I learned that one the hard way. Towering inferno!!!
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