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Topic: My 1972 Comet GT (Read 16759 times) previous topic - next topic

My 1972 Comet GT

Reply #30
Quote from: thunderjet302;451462
Ouch. Needs more gear big time. Even my tub-o-lard Thunderbird can pull 8.90s in the 1/8th mile on street tires (with a 2.2 60' :banana:)
My 60ft was a 2.18 on street tires, was actually surprised it got out of the hole that well(does have a 2000 Hughes converter)... I have a Traction Lock hat for the 8", just having a hard time deciding what gear... It cruises nicely on the 3.00 but a 3.80(common 8" ratio) would be far better at track... If I were to swap the C4 for a AOD(have two useable spares), the 3.80 would be a no brainer...

It seemed really slow after running the Bird & Marauder(but I had predicted a 9.2).. The Marauder could pull 1.87-1.89 on it's Factory BFG tires, Bird needed drag radials to get a 1.90(best), both ran best 8.40/8.42 in the 1/8... Amazing how similar they'd ET, Marauder did run 85 which was a couple MPH better than T-Bird... Guessing it could have busted into 12s with that speed, that boat would really roll once boost was up...

My 1972 Comet GT

Reply #31
Is it spinning off the line? When i'm pulling 2.2 60's in my Thunderbird it's because it's spinning.
88 Thunderbird LX: 306, Edelbrock Performer heads, Comp 266HR cam, Edelbrock Performer RPM intake, bunch of other stuff.

My 1972 Comet GT

Reply #32
Quote from: thunderjet302;451476
Is it spinning off the line? When i'm pulling 2.2 60's in my Thunderbird it's because it's spinning.

Slightly, "chunk - chunked" a couple times and went on down the track... It didn't use enough of the gear to get out of 2nd, so it could be said it was running a 'Glide with a 4.38 rear... Still doesn't really help that 2K stall...

Guessing with good tires and gear it could pull a 2.0, but the 306 doesn't makes enough power to rival what the old Trick Flow headed 5.0 could..


What MPH did you turn??

My 1972 Comet GT

Reply #33
1/8 was 8.9@78. 1/4 was 14.1@98. Mind you this is a car that's 700lbs heavier. With traction it's got mid 13's at over 100 in it.....
88 Thunderbird LX: 306, Edelbrock Performer heads, Comp 266HR cam, Edelbrock Performer RPM intake, bunch of other stuff.

My 1972 Comet GT

Reply #34
Quote from: thunderjet302;451481
1/8 was 8.9@78. 1/4 was 14.1@98. Mind you this is a car that's 700lbs heavier. With traction it's got mid 13's at over 100 in it.....


Uummm, yeeahhhh but I've always heard tire spin only reduces trap speed slightly... Reason being you aren't moving(much) while spinning, so still have approx same distance to make your speed... No doubt kills the ET by half second or more...

So where's my old ET log book for Bird(that no doubt weighs approx same as yours)...

Ahhh here it is...

First run ever on street tires, spun so bad it had a 2.42 60ft, still went 14.46@99.3 mph... Next run I broke the input shaft so aborted just after half track but short timed 2.17... 1/8 mi time dropped from 9.49 to 9.20, speed was 78.4 on both runs...  That was when it had a 2K B&M converter and 19Lb injectors with stock 55mm MAF meter...

Once I swapped to 2600 stall, 24Lb inj & 76 Pro-M MAF injectors, it pulled a 1.96 on some soft Michelin street tires(yeah that was a surprise) and went 13.56@101.5

Next outing was on a 95* day at Fun Ford, had installed full 2.5" exhaust(prior had some stock 5.0 Stang junk under it)... That day engine temp was over 230* and only pulled 2.07 60ft(still on those Michelins)but ran 13.65, speed increased to 102.6...

Three weeks later with 70-ish temps and exact same combo, it went 1.98 60ft and 13.38@ 103.91... Exhaust system was worth almost two tenths & 2.5MPH... Next time I raced it was a couple months later, it pulled 1.98 and ran 13.40@103.7... Three additional runs with short belt(P/S bypassed) it went 13.33 & two 13.34 at 104.0, .7 & .3...

Finally just prior to end of season I  installed fresh plugs and bumped the timing slightly, that night it went best ever on motor of 1.90 & 13.11@105.32, with a backup run of 13.23@104.7... I think it had gotten too cold on that run, so oil and gear lube were getting thick since it was 45* I probably should have warmed it up more...

My 1972 Comet GT

Reply #35
I don't expect it to run 105 or anything but more in the 100 to 101 range. As it sits the car gains both et and mph if I can get it to 60 foot lower. Last year if it pulled a 2.3 60 foot it would consistently run 14.3@97. Pull a 2.2 60 foot and it would go 14.1@98. I figure a 1.8 to 1.9 60 foot should result in 13.6 to 13.7 @ 100 to 101 or so. I'm going to try and run it again this weekend.  I haven't run it with the Performer RPM intake yet. It's supposed to be sunny and 61* both Saturday and Sunday so pretty much perfect weather.

Back on topic but what heads are on the Comet?
88 Thunderbird LX: 306, Edelbrock Performer heads, Comp 266HR cam, Edelbrock Performer RPM intake, bunch of other stuff.

My 1972 Comet GT

Reply #36
Quote from: thunderjet302;451485

Back on topic but what heads are on the Comet?

Pro Comps, were on engine when I bought it... Was built by a guy working at local performance machine shop(I think he swept floors), had never been run when I got it... Had a rumpy Wolverine cam in it(forget specs), that I gave a friend... I pulled it down and he inspected valve components, plus went through the short block to be sure it was machined/assembled correctly... I bought the Weiand intake, and more street friendly cam... I also got the EFI E'brock intake and 70mm TB, plus new 30Lb inj & matching MAF meter in the deal...

BTW It's said not to do a burn out at track on street tires, but I found a good smokey and SLOW roll to line worked for me... Heat in tires picks up some rubber & traction compound, the slow roll cools them somewhat so tires are sticky on launch... If too hot the soft rubber rolls of the hard tread and acts almost like grease... No won't equal DR(tho the Michlins I mentioned were super) but unless tires are very hard, most assuredly helps...

Good luck, knock one out of the park...

My 1972 Comet GT

Reply #37
What cam is in it now? Maybe the Comet just needs some more cam. Those 30lb injectors and MAF will come in handy with the 331 in the Bird.

I may try a burnout at the track just for fun. I'm going to do it after a regular run just to verify it makes a difference.
88 Thunderbird LX: 306, Edelbrock Performer heads, Comp 266HR cam, Edelbrock Performer RPM intake, bunch of other stuff.

My 1972 Comet GT

Reply #38
Quote from: thunderjet302;451499
What cam is in it now? Maybe the Comet just needs some more cam. Those 30lb injectors and MAF will come in handy with the 331 in the Bird.

I may try a burnout at the track just for fun. I'm going to do it after a regular run just to verify it makes a difference.

Comet has a Lunati 207/213* with around .470/480 lift(rounding off here), smooth idle over power was the preference...

BTW on launch bring RPMs to near the max it'll stall and just lift brake foot, let it roll for approx half length then start opening throttle, should be able to be WOT by 25-30ft... Of course if you had some stickies, you'd slap the petal & go...

My 1972 Comet GT

Reply #39
That's a tiny cam. A little more cam, 2800-3000 stall, and some 3.73s and that little Comet would, well, be a comet ;).
88 Thunderbird LX: 306, Edelbrock Performer heads, Comp 266HR cam, Edelbrock Performer RPM intake, bunch of other stuff.

My 1972 Comet GT

Reply #40
Did you make the track?

My 1972 Comet GT

Reply #41
Quote from: TurboCoupe50;451606
Did you make the track?


Not this weekend. It rained Saturday. Sunday the track had a "special event" and wanted $55 for a test and tune session :wtf: (usual price is $30). I'm going to try on the 17th or 18th of the month.

It's about an hour and twenty minute drive to the track (90 miles ish and in Wisconsin) so I want to make sure that when I go I can get a decent amount of runs in. The closer track to me (Joliet) shuts down at the end of September but the one in Wisconsin shuts down after the first week of November. Go figure.....
88 Thunderbird LX: 306, Edelbrock Performer heads, Comp 266HR cam, Edelbrock Performer RPM intake, bunch of other stuff.