Gre975

Hi all,

I recently rebuilt my 350 in my 1971 Cutlass S. the specs are as follows:

1971 350 with #7 heads bored .030. Stock small valves and Scorpion pedestal rockers. Speedpro flat top pistons and corteco .028 mls head gaskets for a total of 10.6 to 1 cr.

Comp camshaft with 234/240 duration at.050 532/541 lift. 112 lsa 107 lca. New Holley 750 vacuum secondary with 70 jets and float level set so gas dribbles out of sight screw. Stock points distributor with Pertronix Ignitor 2 conversion and coil.

Hughes 2500 TC in a th350. 3.42 gears and 28" tires.

My problem is this. I set initial timing at 14 degrees with 40 total. When I took it for its maiden voyage, it idled great in park. While driving I would come to a stop sign or slow down for a corner and it would sputter and die. Also, it lacks power in the bottom end but runs great once it gets up to about 25 mph.

At first I thought it was a fuel issue so I bought a new Holley but the problem persists. I checked for vacuum leaks under the hood with carb cleaner to no avail. When I hooked up the vacuum advance my initial timing jumps to 40 degrees so Ive left that unhooked. I don't know where else to look. Any advice or help will be appreciated.

Gre975

I forgot to mention, vacuum was measured while in park and idling at about 10 hg. A compression test showed all cylinders were averaging between 185-195. Also I have an Edelbrock Performer RPM intake and hooker headers to a dynomax 2 1/2 ' system.

seansolds

Sounds fuel related. How do you have your fuel line set up? Is their a return, what is your fuel pressure set at? And your idle RPM set at? Also do you have proper tank ventilation?
Sean

oldcutlass

What is your idle rpm set to, and how far does it drop when put in gear?

Gre975

I don't currently have a tach hooked up yet and I haven't measured fuel pressure. I did turn idle speed way up when in park and it still would die when put in drive or reverse.

don71

I once had this problem, but this would be an apples to oranges comparison. My set up was/is different.

I found my problem in the distributor. Double check your weights are not sticking and moving freely. I eventually replaced the entire unit.

I would look at the ignition first then carb/fuel. There is a chance this is something simple.

Gre975

Well after looking at it again, I'm thinking my stall speed is too low for the camshaft. I called Comp Cams and the tech said the operating range was 2400-6000 rpms. I will be borrowing a 3000 rpm stall next week and see how that works. Anyone have any thoughts on this?

Gre975

Ok after getting a tach installed it seems the problem was too low idle speed. Also, turns out my Hughes TC was a dud. I sent it back and ordered a new one. Should see a marked improvement with the new one.

coppercutlass

im a bit late to the party but i was going to say it probably needs more stall than 2500 and a little more gear wouldnt hurt it . Some times a little more initial timing works. I had a set up with a really tight converter and i had to tune the carb to run a little rich at idle and i had to use the unported side of the vacuum port for the vaccum advance to help it idle in drive.

Gre975

Its been a while but I thought I'd post my results. After returning a defective converter and ordering a Hughes 3000, car runs perfect. This converter is perfect for my setup.

oldcutlass

That was where I was going with my questions, glad it worked out.