Hey guys, I'm hoping you can point me in the right direction here, cause Im a little lost. I just installed a brand new Blueprint engines 350 into my 34. Its got a tunnel ram intake with dual 450cfm QFT carbs and its got a mallory distributor with a MSD 6AL box. I have the ignition set to 16deg (what blueprint motors say to have). No vacuum advance. The motor cranks over instantly, idles great. However, when I take it around the block it feels like the timing starts to retard like crazy under load. I'll be cruising at 15mph in 3rd. I start adding some gas and it just starts to stutter and misfire. I have to rev it up in neutral again, drop it into 2nd and it pulls again. Under load, mid throttle it just feels like its cutting out. When revving it up, I looks like its running rich. I checked the float bowls and theyre all right at the correct level. What else could it be?
Well it maybe 25...the point is that when in a higher gear, the load is bigger, part throttle, car is just choking.
Does the 350 have a stock cam in it? Reminds me of my mother, she kept complaining about the dash in her Plymouth shaking. The Plymouth had a treespeed that she would have in third at ten miles an hour.
Are you stating that it's 16 degrees total? Locked out? No advance? Or are you saying it's set at 16 initial with the vacuum unhooked and plugged off? What's in the distributor? 24 degrees?
Funny thing, "lugging" like that - low speed in high gear is an old school quick torture test for the ignition system, especially spark plug wire insulation and other ignition components. If arcing or crossfire is going to be an issue that's one way to find it. I think probably more modern dielectric materials and insulation made that problem go away, but it may well be ignition related. Something to rule out maybe.
"Just pull the choke all the way out, Mom! Great place to hang your purse, too. It'll fix that shaky dash right up."
Crank it around to about 28 degrees, see if it heals up. Might be locked out, or might have way too heavy springs on the weights in the distributor. If it's locked out, you should set it around 34.
I don’t think timing is the issue here. I think tuning dual carbs on a tunnel rammed engine is more of an issue.
I think I'd look at carburetion. Unless your MSD box is handling your advance and is real messed up, I can't see your distributor doing what you said. It sounds more like a lean condition on initial acceleration.
16 degrees initial, no vacuum at all. I havent checked what the total timing is cause I have no friends to rev up my engine . I will check, maybe the avance is stuck.
Downshift! No car/engine likes to pull away from a low RPM circumstance in top gear. Use the stick to get in a lower gear (more RPM) as you apply more throttle.
Depending on final drive, at least 2nd gear. If tunnel ram equipped probably 1st gear. I've never understood why some go for manual gearbox or manual shift automatics but won't change down when required. I'm a 40 plus year career truck driver (retired) but still a gear jammer at heart. The more gears to row the better.
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