First time out.... waa waa waa waaaaaaaa !

Thanks Larry I will check all those variables ..throttle swing is maxed out though I know for sure...I am not running the carb adapter on top of the intake though so maybe vacuum isnt what it "could be" although its pulling 15-16 at idle which Jim W. says is about right for a "tightly sealed up motor" . with my exact cam. I am going to install it anyway . I am running the dist like you suggest running more initial - limiting vac advance with an advance can stop, running 15 initial and I have the 18 degree mechanical stop in there...the fattest one for a total of 33. I will double check it with a timing light this weekend however.

Lets do some interesting math ....

Now according to desktop dyno my engine should produce roughly 330 hp and 440 ft lbs...a little low I thought but lets go with that number. My ET according to the calculators indicates I only have 290 at the crank on my BEST run with 20% driveline losses figured in. So it must be all due to sheer traction losses or I have lost 40 hp somewhere. Because my trap speed sucks I think maybe I AM down on h.p. BUT the thing runs so great I have a hard time believing I am down 40hp. Using the 330 hp figure from desktop dyno I should be running 13.65 at 99 mph at minimum +4 more mph than my best mph ..If memory serves me correct -10 hp = +.10 to your et so -4 mph = 40 hp lost ! Is that a coincidence, the same figure the calculator indicated I was down ! In conclusion it looks like I am down ~5 mph, ~1.2 secs and 40 hp possibly from where I should be. Some of this is positively traction but the mathmatics are really interesting in this case pointing to a -40 deficit possibility. Who knows its all magic ! Thoughts ? J .

I also realized tonight peak hp according to desktop dyno in my motor is at 4500 rpm not 5k in my engine. I was shifting at 5k so I would imagine there is a small penalty there for doing that also correct ?



. I have owned many cars , built 5 motors and I owned a previous 72 G.s. I installed a 455 I built the 80's but this motor feels stronger than that Buick allthough my other car ran 13.67 at 97 mph with a 3:08 non posi. Some things crossed my mind today ...would I be better off delaying my mechanical advance with stiffer springs and installing a carb spacer to try to scrub off some low end torque and moving the power up higher in the rpm range to deal with the single side OR would that all be counter productive in the end ?

I am missing 40

 

Well the 308's to 256's is a world of difference to begin with. Now I would put an air bag back in that corner.

And me personally, I don't care for the Quadrajet for the track. Awsome for street pounding.

You need to get a decent tire on your peg legger.

Always favored the vacuum secondary carbs.

Now I have an 850 demon!

 

Thanks guys ...Joe as I recall when we talked on the phone your car runs pretty well....whats your motor build / car / best time so far .....p.s. I am running an Edelbrock Thunder series 800 cfm vac sec carb. Joe - what tire rim combo are you running on the back ? J

 

Just put some sticky tires on the back and try it again!

 

Ok so tomorrow Wednesday 12-19-07 with the following "enhancements" I am headed to the track one more time in my 65 to try to hit a high 13 ......from my best / terrible 14.85 at 95 .

1.) Ground out intake obstructions in Performer intake secondary throats.
2.) Will lockout choke with a tie wrap to make sure secondaries fully open bypassing "cold" secondary lockout feature on the Thunder series carb.
3.) Installed 1/2 inch phenolic carb spacer ...trying to shift some power up
a little rpm wise and get carb cooler- it was pretty hot last time.
4.) Installed a Powertrax no slip unit in my peg leg 2:56 rear
5.) Unfortunately I couldnt get any tires to play with. So 255-45-17 Nexxens again.
6.) Factory fan and clutch vs straight flex fan I had on there last time.
7.) 2 ft -slightly larger fuel line from pump to carb - braided stainless ,routed differently away from block to run cooler.

If I hit a 13.9x I will be elated....my gut / math tells me with these improvements I will only at best run a 14.00 at probably 98. I hope I am wrong. I also will strive to get out of the hole- 60 ft in the low 2's. Wish me luck that the new Powertrax and my 42 year old rear end hold together and that I dont break anything ......John

 

You should improve well just by the better traction, it will be interesting how well it will launch with that high of gear though. Sounds like your on the right track, try it with and without the spacer if you can, sometimes they hurt performance or require jetting changes. Good luck!!

Steve

 

I still think a passenger-side airbag will help!

-Bob C.

 

Thanks guys ...Bob I tried to get ahold of a bag but couldnt do it by tonight,,,,its the last night for open test and tune- so its tonight or never for this year . I agree it probably would help. The other night when I nailed it with the fresh power trax install I noticed severe wheel hop-shudder...a buddy told me new shocks will get rid of alot of that- has that been your experience too ? Will post results tonight when I get home ......Thanks J.

 

When I went to a 3.42 posi in my 71 GS455, I had wheel hop pretty bad too - and that was with an air bag. What fixed it was sticky tires. I went to some DOT drag tires (Hoosier Quick Time Pros, for instance) and never thought about wheel hop again.

 

I used to have wicked bad hop. A few things helped it, but the biggest thing was new control arms (mine were very tired after a few hundred thousand miles). But my springs were also too tall, that didn't help.

 

I was running original upper rear arms, but the lower rears were Hotchkis on that car.

 

The good news is the Power Trax unit appeared to work fine on my one run my time was terrible with a bunch of wheelspin on the 255 street tires ..my 60 ft was 2.48 - the same as my best 60 ft with no posi....... .the bad news is I smoked my brand new motor with less than 1000 miles on it. It sounds like I have spun a bearing. It has a rattle that is barely noticeable at idle but as soon as you give it gas a horrendous lower end rattle from the oil pan is heard. I have put so much time energy and resources in this thing over the last year I am totally disgusted. Makes me want to get out of the hobby alltogether. I will probably throw the cover on it and after the holidays pull the motor and do a post mortem. When I do I will post pics. J.

 

Dude, that's horrible, I'm sorry to hear that.

If/when you decide to uncover it, be sure to post to the board and we'll help diagnose & fix it.

-BC

 

Thanks Bob ...I will. J

 

Ohhh Man !! Sorry to hear about the motor ... I tuned in this morning to see how you did.

... if it makes you feel any better I've been there too

 

Thanks Alan.....I have built 5 motors over the years Chevy,Buicks...this was the only one I DIDNT put the bottom end together in - it was already done... I only checked his torque specs on all the mains and rods....so I guess you live and learn. If this one is hurt too bad I may do the unthinkable and jump ship and throw a small block Chevy in it. I still cant believe this thing came apart......anyway thanks for the encouragement ...check back in a few weeks and I probably will have yanked it and posted pics of the carnage by then ...John

 

I'm really sorry to hear this. Do you think it had anything to do with the metal shavings from grinding out the intake on the motor? Either way it sucks.

Let me know if you need a crank. I might have a good one to donate to the cause.

 

Thanks Mike I may take you up on that crank....metal shavings - no I was super carefull and stuck a ton of rags in the intake, vacuumed etc ....early on I had a light clacking in the engine but chalked it up to the noisy lifters everyone is complaining about...it seemed like it was coming from the valve covers and I was running .490 lift ..looking back the noise had gotten slightly - progressively worse ..My early theory now is the motor is exhibiting unreal bottom end power - so I think I have wiped the cam lobes to the point it thinks its an rv cam now ...the garbage got into the oil and into the motor etc etc...allthough it really sounds like a rod knock when you lightly hit the accelerator .....I may pull a few bolts on it this weekend...I was trying to leave it alone and stay away and take a much needed break over the holidays but the suspense is killing me ......I want to know what happened...keep me in mind for that crank I just may need it ...is it turned ..010 or stock ? Thanks again Mike........ . John