My old school 340 upgrades and results.

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A little update. I ran the car today. I learned a few things need to be addressed.
Finst I ran the car with a 50 50 mix of 100LL av gas and premium pump gas. Rear tires at 10 psi. Timing at 34 degrees locked.
I launched and botched the 1 2 shift. I had my hand resting on the shifter so it shifted to 2nd right as I left. I pushed it back to first and the car started getting squirrely. I had trouble keeping it in my lane. I lifted and coasted to 16.83 68 mph.
Next pass I put rear tires to 13 psi. I didn't get my launch rpm where I wanted and basically was idling when the light went green I launched and ran down the track bit lifted at the 100 foot mark or so. Got a little squirmy but way better than before 12.83. At 90.
1st round eliminations comes and I have not made a clean pass. I throw 12.50 on the window and hope for the best . I run 12.67 107 but my rt was .126. The other car runs 12.44 on a 12.24 dial. Is rt is .032 or something. I was closer to my dial but lost on a hole shot. I make a other pair of time only passes in the 12.65 range.
I have some work to do. My tires are old and need to be replaced. That is first order of business. After that I think I may freshen the motor up with a valve job and removed ring.
I was hoping to go faster but I am giving up to much at the launch. I also need more seat time and work on rt. I am happy with the day though. Car ran ok. Didn't blow up. Tires didn't shred and put me into the wall. Good day lol I didn't do any tuning on it as I was mainly worried about just getting some passes under my belt.
 
gtsdude said:
That's a decent number for first time out, no breakage is even better.
Click to expand...
In all actuality I should have replaced the tires before I went. I was most nervous about the tires coming apart on the top end. Next time out she will have some new tires.
The heat was terrible out there Nothing like sitting in the staging lanes waiting for your class in 106 degree heat with a helmet on . Every time I took my helmet off to wipe the sweat from my eyes he would motion to his head to tell me to put it back on.

I did wind up shredding a tire on the trailer on the way home so that was another 2 hours sitting in the heat while we located a replacement tire.

Also for the record the motor had no problem revving past 6500 rpm. Videos will be coming soon.
 
Wallace calculator shows a few tenths in it with your mph, get the 60 foot down, new tires should help that, along with a little tunning. The heat probably didn't help either, I think low 12's or high 11's are in your future in better conditions.
 
I watched the video and it feels like it could use some more bottom end and rpm at launch. I think freshing up the motor and few smart minor changes will have me where I want to be. It sounds like it labors just a bit when I launched. I didn't hear it at the time but the in car cam makes it sound obvious
 
60 foot was 1.845 to 1.848. Stall measured and what I was originally told are different things. It seems to stall about 2900 to 3000. Years ago I seem to remember being told it had a 4800. My memory may be mistaken.
 
20160620_213024.jpg
 
Ignore the reaction time. After running off of a standard sportsman tree I went up for test and tune. Unexpectedly I had a pro tree.
 
It think it would definitely benefit from a higher stall converter, I think the 3800 stall behind my 340 is a little low as well. I still have not made it to the track since I swapped cams, springs and did a little grinding on the heads. The MP 557/296 cam I swapped in is similar to the 509/292 only a solid cam. If I run close to your numbers first time out, I will be happy.
 

Current rear tire is 31-13 R15 I would like to put a 29-12 on there. I have a 4.30 to 1 rear gear.
 
Not near enough gear for a 340 with that size tire.

As you mentioned, a 28 or 29" tire will make a difference in how the car leaves.
 
Sorry about the double post. I can't seem to figure out how to delete one.
 
crackedback said:
Not near enough gear for a 340 with that size tire.

As you mentioned, a 28 or 29" tire will make a difference in how the car leaves.
Click to expand...

X2 I ended up with 27 inch MT drag radials and a 456 rear gear, what's your trap rpm? I had a 26 inch tire and 410 rear, used to trap at 5800, new set up should be 6200-6500 through the traps.
 
Not sure on the rpm I will have to review the video on a larger screen to hopefully read the tach. There is a set of 28 12 MT ET streets for sale (bias) I am looking at
 
340dartley said:
Not sure on the rpm I will have to review the video on a larger screen to hopefully read the tach. There is a set of 28 12 MT ET streets for sale (bias) I am looking at
Click to expand...

Going from 31-28 inch tire,
Calculator says about 5000rpm at 107 mph with your gear and 31 inch tire, about 5500 with 28 inch tire. Converter slip isn't taken into account though.
 
Definitely plan on the smaller tires. I am starting to look for a looser converter as well. I also think there is more in the motor. I did hear a little bit of an audible air leak on a few of the exhaust valves when I had the cylinders pressured up for the valve spring change. The heads haven't been off since 1981 allegedly.
 
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