89305formula

iTrader: (5)

so i went to the track last night hoping for a 12.5 pass, but the best i could get was a 13.4, the last time i went it ran a 12.7 at 107 and it wasnt running all that good at that time and since then ive rebuilt the carb, switched from a weiand dual plane manifold so a single plane weiand, and put in a msd pro billet distributor. the car was leaving really hard at first then falling on its face, it was lifting the front tires about 6 inches then bogging down the best 60ft of the night was a 1.897 where the 12,7 pass was a low 1.7 i belive but i dont have the old slips in front of me. any ideas why i would have lost 7 tenths and almost 6mph
i should have some videos of it soon my sister is suposed to be emailing them to me sometime today

atc3434

iTrader: (4)

Wow, something significant happend between those two trips to the track, you don't lose 6mph and .7sec from bad weather. If it was hitting hard then dying out I'd say thats a fuel delivery problem, maybe jetting or even starvation. I guess could have been breaking up in the higher RPMs, but you'd think you'd have heard it enough to know. If the car is hitting good on the bottom it would seem the advance is appropriate on the distributor, so my money is on the fuel. You would think a single plane would have been the opposite, a little softer on the bottom with lots more on the back half of the track. Lets see those vids.

89305formula

iTrader: (5)

im not to sure about where the timing is cause i think the balencer spun, the timing light was telling me i had 30 degrees of base timing and over 60 full advance, so i brought it up to 4,000 rpm and tried to set it be ear. my air fuel guage just came in today so im about to put that in and see where i stand with that, im hoping its way off cause it didnt seem to pull on the big end like it use to so im thinking its going lean up top, but ive never had it bog so bad off the line, by the way im launching it at 6200
and 2 of my 60fts were 1.9s 1 was a 2.074, all three of those it dead hooked and ran a 13.7, and on my last pass i barley did a burnout so it would spin a little out of the hole and thats when i cut the 1.897 60ft

atc3434

iTrader: (4)

I must have mis-understood, I thought it was leaving hard the night it ran slow, then was dying. Slow everywhere and timing set by ear = probably no where near enough advance. If the balancer is off, you need to get that right first, because you gotta know where the timing is at. By ear can get you in the ballpark, but not much better.

I remember when I finished my carb/ignition swap from the CCC-Qjet and distributor to the vacuum advance distributor and Edelbrock carb, I set the base timing, but accidently bumped it back when tightening down the distributor. I took the car for a ride and it was just DEAD everywhere. I went through everything on the carb, I thought the secondaries weren't opening, then I thought it was super lean, checked for fuel starvation. Came to the end of all that and figured I'd throw the timing light on just to be sure. 1* of advance on a Summit HEI that only have 16* mechanical. There was my problem. Dialed up 14* initial, checked it again after getting it tightend down and holy hell my little 305 woke up right up.

I'd get the timing right, for sure, then I'd worry about other stuff if it still doesn't run like it should.

89305formula

iTrader: (5)

yea thats kindda what i was thinking, i just found my old balencer at my parents house so im going to compare where the mark on the balencer is to the key way to my old one.
i dont think you mis understood it was leaving hard for the first couple feet then falling down, and i tried launching everywhere from 3500 for 6200

five7kid

iTrader: (14)

You've got to know the timing is right before you can expect decent performance.

Single plane intakes are not very forgiving. I thought 3500 stall and 6800 upper end powerband cam would work well with a single plane, it cost me a tenth in 60', even though it didn't bog.

atc3434

iTrader: (4)

Ok, got it. It would make sense that with aggresive gears and good traction launching w/ those rpms would hit hard right off the bat, but if it wasn't running right would fall off almost instantly.

five7kid is pretty on the money as well, the cam your running isn't tiny by any means, but might not be exactly single plane material. I say get the timing worked out, and try it again on the single plane. If it still can't knock down close to your original time, you'll find your way back to the dual plane.

Let us know how it works out - always like to see 305's going fast! I'm thinking the Vortec .525 lift heads and Performer RPM Airgap from Scoggin Dickey's for me this year, with a similar cam, probably the XE268. Any more than that and I'm gonna really feel the need for more converter. But I am curious, how does that xr274hr work for you? Whats the idle like, and where does the power start, and fall off?

89305formula

iTrader: (5)

well the balencer didnt spin, i check the timing and it was 32 base and 65 full advance i brought it down to 15 base and 45 full advance and it backfire through the carb when given throttle off idle, is there any other reason the timing would need to be so high, im going back to a dual plane tonite and hopefully going back to the track tomorow

atc3434

iTrader: (4)

When you say full advance, thats just full mechanical advance, not with any vacuum, right? If so, thats a LOT of advance, SBC's don't typically take more than 34-38* total, all by around 3200rpm. (For WOT - obviously vacuum advance at cruise goes 50*+) I suspect you might still have some timing advance issues, its sounds like you're timing was really weak to start with (the 32base/65full) and was actually retarded with the 15base/45 full - hence the carb backfires. It might be worth manually checking the timing marks, its a pain, but probalby worth the time if its acting up this much - those timing numbers are definetly way way off.

327???

Check the timing with the vacuum advance disconnected, 45 is too much and 65 is WAY too much if the vac advance is disconnected..

89305formula

iTrader: (5)

its a mechanical advance distributor, what would be a good base timing, how do i check it manually, also could it be something stupid like the dizzy a tooth off or all the wires on the cap one spot over, i say that cause when i had it out the other day i marked all the wires but forgot to mark number one on the cap so i guessed and it did fire up after moving the dizzy around some

five7kid

iTrader: (14)

Hook the timing light up to the #1 or #6 spark plug wire. You have to get the right wire, you can't just pick any of them.

Having the distributor off one tooth won't affect anything - just move the distributor housing until you get the proper timing.

So, your distributor has mechanical advance only, and no vacuum advance?

89305formula

iTrader: (5)

yea its a msd pro billet 8551 is the part number i belive, i just set it with a light 10 base 36 full advance and it seems to be running good,i also just got finished putting my air fuel guage in and its in the rich area at all rpms, how do i lean it out at idle, i have a 6.5 powervalve and 13 inches of vacuum should i go leaner in the primary side